ORCID Profile
0000-0002-5986-9136
Current Organisations
Sun Yat-Sen University
,
Organisation
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University of Wollongong
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Central Nervous System | Health Promotion | Marketing Communications | Public Health and Health Services | Biosensor Technologies | Engineering/Technology Instrumentation | Neurosciences
Behaviour and Health | Substance Abuse | Nervous system and disorders | Medical instrumentation | Scientific instrumentation |
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2020
DOI: 10.1097/HP.0000000000001169
Abstract: Cosmetic devices using non-ionizing radiation (NIR) are increasingly available for people who wish to modify their appearance for aesthetic purposes. There are a wide range of NIR modalities used for cosmetic procedures, including devices that use optical radiation (laser, intense pulsed light, and light-emitting diode), electromagnetic fields, and ultrasound. Common procedures involving the application of NIR include epilation, skin rejuvenation, body sculpting and contouring, treatment of vascular and skin lesions, tattoo removal, and scar reduction. The majority of research on the use of NIR cosmetic devices has focused on the efficacy of the treatment rather than adverse effects or complications. Studies that assessed safety consisted mostly of case reports and small case series. Common adverse effects on the skin reported include mild and transient pain, erythema, swelling, and changes in pigmentation. Less common, more severe side effects include burns, blisters, scarring, persisting erythema, altered pigmentation, and eye damage. Some of the latter may have resulted from treatment errors. Particular groups of people that may be at greater risk from optical radiation include people with dark skin, with high sun exposure, and taking photosensitizing medications or supplements. There is lack of evidence for the safety profile of cosmetic NIR procedures during pregnancy. Reports of injuries to workers administering treatments with cosmetic NIR devices are rare, but inadvertent damage to the eye from optical devices may occur. Randomized controlled trials are required to fully assess potential adverse effects from the use of NIR cosmetic devices. Regulation varies worldwide and some regions apply the same safety classification and guidance as for medical devices. In order to reduce harm associated with the use of cosmetic devices, ICNIRP considers it important that regulations that cover all types and frequencies of cosmetic NIR devices are adopted worldwide and that there is greater oversight regarding their use.
Publisher: Elsevier BV
Date: 04-2023
Publisher: Wiley
Date: 29-06-2010
DOI: 10.1002/HUP.1133
Abstract: The loudness dependence of the auditory evoked potential (LDAEP) has been proposed as an electrophysiological marker for assessing serotonergic function in vivo in humans, although accumulating evidence suggests that it is insensitive to acute changes in serotonergic neurotransmission. Very little is known about the sensitivity of the LDAEP to other neurotransmitter systems including the noradrenergic system. The current study examined the effects of noradrenergic modulation as well as serotonergic modulation on the LDAEP. The study utilised a double-blind placebo-controlled design in which the LDAEP in 17 healthy males and females was tested following acute administration of each of citalopram (20 mg), reboxetine (4 mg) and placebo. Neither citalopram nor reboxetine modulated the LDAEP relative to placebo treatment (p > 0.05). These findings suggest that the LDAEP is insensitive to acute changes in serotonergic or noradrenergic neurotransmission and thus is a poor pharmacodynamic marker of these systems.
Publisher: Elsevier BV
Date: 07-2012
DOI: 10.1016/J.EURONEURO.2011.11.009
Abstract: While a number of behavioural studies have been conducted to investigate the acute effects of hetamines on tasks of attention and information processing, there is currently a scarcity of research concerning their electrophysiological effects in healthy adults. It is also unclear as to whether hetamines exert effects on stimulus evaluation or response selection. In two studies, independent groups of twenty healthy illicit stimulant users aged between 21 and 32 years were administered 0.42 mg/kg d- hetamine versus placebo, and 0.42 mg/kg d-meth hetamine versus placebo respectively, and completed an auditory oddball task on two separate testing days. A 62-channel EEG was recorded during the completion of the task, and the effects of hetamines on N200 and P300 ERP components were analysed. d- hetamine significantly decreased reaction time, improved accuracy, and reduced the latency of the P300 component relative to placebo, while having no effect on the N200 component. d-meth hetamine had no effect on reaction time, accuracy or the P300 component, but reduced the litude of the N200 component, relative to placebo. It was concluded that there is tentative support to suggest that d- hetamine at a dose of 0.42 mg/kg may enhance speed of information processing while d-meth hetamine at a dose of 0.42 mg/kg may reflect changes to stimulus evaluation.
Publisher: Elsevier BV
Date: 09-2001
DOI: 10.1016/S0006-3223(01)01082-4
Abstract: P50 suppression is an electrophysiologic index of early sensory gating and has consistently been found deficient in schizophrenic patients. This gating deficit is thought to lead to sensory overload and cognitive fragmentation, and correspondingly many symptoms of the disorder. However, the link between P50 suppression deficits and symptomatology is yet to be established, and so this study was designed to determine whether such a relation is present within a nonclinical population. P50 suppression and schizotypy measures were obtained from 36 healthy volunteers, and correlation analyses determined whether measures of schizotypy were related to P50 suppression. Consistent with the view that P50 gating deficits are related to schizophrenic symptoms, subjects with poorer P50 suppression reported more perceptual anomalies and magical ideation--an unreality syndrome--in contrast to other positive symptoms and to withdrawal. This study also found a trend to P50 suppression desensitization, and that whereas subjects low on "unreality" demonstrated desensitization to the second of the paired clicks, subjects high on "unreality" demonstrated sensitization. It is concluded that early sensory gating deficits, in the form of poor P50 suppression, are related to unreality aspects of schizotypy. This supports the view that poor P50 suppression in schizophrenia is related to symptomatology.
Publisher: Hindawi Limited
Date: 2016
DOI: 10.1155/2016/6526437
Abstract: Prolonged heavy exposure to cannabis is associated with impaired cognition and brain functional and structural alterations. We recently reported attenuated mismatch negativity (MMN) and altered P50 sensory gating in chronic cannabis users. This study investigated the extent of brain functional recovery (indexed by MMN and P50) in chronic users after cessation of use. Eighteen ex-users (median 13.5 years prior regular use median 3.5 years abstinence) and 18 nonusers completed ( 1 ) a multifeature oddball task with duration, frequency, and intensity deviants and ( 2 ) a P50 paired-click paradigm. Trend level smaller duration MMN litude and larger P50 ratios (indicative of poorer sensory gating) were observed in ex-users compared to controls. Poorer P50 gating correlated with prior duration of cannabis use. Duration of abstinence was positively correlated with duration MMN litude, even after controlling for age and duration of cannabis use. Impaired sensory gating and attenuated MMN litude tended to persist in ex-users after prolonged cessation of use, suggesting a lack of full recovery. An association with prolonged duration of prior cannabis use may indicate persistent cannabis-related alterations to P50 sensory gating. Greater reductions in MMN litude with increasing abstinence (positive correlation) may be related to either self-medication or an accelerated aging process.
Publisher: Elsevier BV
Date: 2004
DOI: 10.1016/S1388-2457(03)00313-4
Abstract: Due to the widespread use of mobile phones (MP), it is important to determine whether they affect human physiology. The aim of this study was to explore the sensitivity of auditory event-related potentials to electromagnetic emissions. Twelve participants attended two sessions, 1 week apart. Participants performed an auditory oddball task while they were exposed to an active MP during one session and sham exposure during the other. Each condition lasted 1 h and order was counterbalanced. N100 and P200 latencies and litudes were analysed for non-target waveforms, and N200 and P300 latencies and litudes were analysed for target waveforms. In real relative to sham exposure N100 litude and latency to non-targets were reduced, with the reduction larger over midline and right hemisphere sites. P300 latency to targets was delayed in the real exposure condition, however as this difference was greatest at left frontal and left central sites the interpretation of this result is unclear. Reaction time increased in the real relative to sham condition. No difference in accuracy was found. The results suggest that MP exposure may affect neural activity, particularly in proximity to the phone, however caution should be applied due to the small s le size.
Publisher: Elsevier BV
Date: 06-2001
Publisher: Public Library of Science (PLoS)
Date: 17-12-2013
Publisher: Wiley
Date: 07-2006
DOI: 10.1111/J.1460-9568.2006.04879.X
Abstract: Evidence suggests that the component frequencies of the electroencephalogram (EEG) are dynamically adjusted to provide particular brain states at stimulus occurrence, and that these facilitate cortical processing of the stimulus. We examined relationships between stimulus intensity, the phase of narrow-band EEG activity at stimulus onset, and the resultant event-related potentials (ERPs) in a passive auditory oddball task, using a novel conceptualization of orthogonal phase effects (cortical negativity vs. positivity, negative driving vs. positive driving, waxing vs. waning). EEG responses to the standard stimuli (50 vs. 80 dB, varied between subjects) were analysed. Prestimulus narrow-band EEG activity (in 1-Hz bands from 1 to 13 Hz) at Cz was assessed for each trial by digital filtering. For each frequency, the cycle at stimulus onset was used to sort trials into four phases, for which ERPs were derived from both the filtered and unfiltered EEG activity at Fz, Cz and Pz. Preferred brain states at various frequencies were indicated by 16-34% differential occurrence within the orthogonal phase dimensions explored. The preferred states were associated with smaller N1, N2 and N3, larger P2 and P3, shorter N1, P2, N2 and P3 latencies, and some intensity effects. These effects reflected the operation of three separate phase-influenced mechanisms, involving anticipatory potentials and prestimulus oststimulus litudes in various EEG frequencies. Results indicate that, even in paradigms with a slightly varying interstimulus interval, brain dynamics provide preferred brain states at the moment of stimulus presentation, which differentially affect the EEG correlates of stimulus processing.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2020
Publisher: Wiley
Date: 12-04-2021
DOI: 10.1002/BEM.22338
Publisher: Springer Science and Business Media LLC
Date: 13-08-2011
DOI: 10.1007/S00213-011-2437-7
Abstract: Illicit drugs such as meth hetamine are commonly abused drugs that have also been observed to be prevalent in drivers injured in road accidents. The exact effect of meth hetamine or its specific isomers on driving and driving behaviour have yet to be thoroughly investigated. Twenty healthy recreational illicit stimulant users (ten males, ten females), aged between 21 and 34 years (mean = 24.3 years, SD = 3.4 years), attended two testing sessions involving oral consumption of 0.42 mg/kg d,l-meth hetamine or a matching placebo. The drug administration was counterbalanced, double-blind, and medically supervised. At each session, driving performance was assessed 2.5 h post-drug administration. Mean blood and saliva d,l-meth hetamine concentrations of approximately 90 and 400 ng/ml, respectively, at 2 h and 95 and 475 ng/ml at 3 h were observed. These levels of d,l-meth hetamine were found not to significantly impair, or improve, driving performance at the 2.5-h post-drug administration time point. The findings of this study illustrate that d,l-meth hetamine has no significant effect on simulated driving performance.
Publisher: Springer Science and Business Media LLC
Date: 19-01-2019
DOI: 10.1007/S00406-019-00978-2
Abstract: Access to cannabis and cannabinoid products is increasing worldwide for recreational and medicinal use. Two primary compounds within cannabis plant matter, Δ
Publisher: Research Square Platform LLC
Date: 28-12-2021
DOI: 10.21203/RS.3.RS-1158065/V1
Abstract: Inconsistencies have been found in the relationship between ambient lighting conditions and frequency-dependence in transcranial electric current stimulation (tECS) induced phosphenes. Using a within-subjects design across lighting condition (dark, mesopic [dim], photopic [bright]) and tECS stimulation frequency (10, 13, 16, 18, 20 Hz), this study determined phosphene detection thresholds in 24 subjects receiving tECS using an FPz-Cz montage. Minima phosphene thresholds were found at 16 Hz in mesopic, 10 Hz in dark and 20 Hz in photopic lighting conditions, with these thresholds being substantially lower for mesopic than both dark (60% reduction) and photopic (56% reduction), conditions. Further, whereas the phosphene threshold-stimulation frequency relation was linear in the dark (increasing with frequency) and photopic (decreasing with frequency) conditions, a quadratic function was found for the mesopic condition (where it followed the linear increase of the dark condition from 10-16 Hz, and the linear decrease of the photopic condition from 16-20 Hz). The results clearly demonstrate that ambient lighting is an important factor in the detection of tECS-induced phosphenes, and that mesopic conditions are most suitable for obtaining overall phosphene thresholds.
Publisher: SAGE Publications
Date: 18-06-2011
Abstract: Estrogen may be involved in schizophrenia by inhibiting serotonin-1A (5-HT 1A ) receptor function. We examined the effects of estrogen pre-treatment on modulation of loudness dependence of the auditory evoked potential (LDAEP) and mismatch negativity by the 5-HT 1A receptor partial agonist, buspirone. Using a double-blind, placebo-controlled, repeated-measures design in healthy female volunteers, we observed that buspirone treatment significantly increased LDAEP slope. Estrogen increased LDAEP slope on its own, and a further LDAEP increase by buspirone was not seen after estrogen pre-treatment. Similar results were observed for mismatch negativity, where buspirone caused a small increase of latency, although not litude, after placebo but not estrogen pre-treatment, which enhanced mismatch negativity latency on its own. These results are in line with our previous findings on prepulse inhibition showing an inhibitory effect of estrogen on the action of buspirone. Taken together, these data suggest that estrogen may inhibit 5-HT 1A receptor-mediated disruptions of auditory processing.
Publisher: Informa UK Limited
Date: 10-02-2016
DOI: 10.1080/15389588.2015.1055327
Abstract: Slow eyelid closure is recognized as an indicator of sleepiness in sleep-deprived in iduals, although automated ocular devices are not well validated. This study aimed to determine whether changes in eyelid closure are evident following acute sleep deprivation as assessed by an automated device and how ocular parameters relate to performance after sleep deprivation. Twelve healthy professional drivers (45.58 ± 10.93 years) completed 2 randomized sessions: After a normal night of sleep and after 24 h of total sleep deprivation. Slow eye closure (PERCLOS) was measured while drivers performed a simulated driving task. Following sleep deprivation, drivers displayed significantly more eyelid closure (P < .05), greater variation in lane position (P < .01) and more attentional lapses (P < .05) compared to after normal sleep. PERCLOS was moderately associated with variability in both vigilance performance (r = 0.68, P < .05) and variation in lane position on the driving task (r = 0.61, P < .05). Automated ocular measurement appears to be an effective means of detecting impairment due to sleep loss in the laboratory.
Publisher: Wiley
Date: 09-2009
DOI: 10.1111/J.1469-8986.2009.00836.X
Abstract: Conventional eye correction methods subtract portions (propagation coefficients Bs) of electrooculogram (EOG) voltages from the electroencephalogram (EEG). The frequency domain approach (FDA) uses different Bs for different frequencies whereas the time domain approach (TDA) uses the same Bs. To determine whether measured Bs are dependent on frequency and whether one should employ frequency-dependent methods, 20 min of EEG from eye movement (EM) and blink data (24 participants) were recorded, and Bs were calculated for eye movement ERPs of differing signal-to-noise ratios for frequency bands ranging from 0 to 40 Hz and compared. At high signal to noise, EM Bs for different frequency bands did not differ, for both vertical and horizontal EOG, at all scalp sites tested. There were small differences in blink Bs for different bands, but smaller than the margin of error of this analysis. This indicates that TDA may be more appropriate than FDA.
Publisher: Elsevier BV
Date: 09-2015
Publisher: Springer Science and Business Media LLC
Date: 20-10-2008
DOI: 10.1007/S00213-007-0976-8
Abstract: Schizophrenia is commonly associated with impairments in pre-attentive change detection as represented by reduced mismatch negativity (MMN). The neurochemical basis of MMN has been linked to N-methyl-D: -aspartate (NMDA) receptor function. Glycine augments NMDA receptor function via stimulation of the glycine modulatory site of the NMDA receptor and has been shown to effectively reduce negative symptoms in schizophrenia. However, no study has investigated the possible effects of high-dose glycine on MMN. Further, the physiological consequences of administering high-dose glycine in subjects with normal NMDA receptor function are unknown. The aim of the present project was to investigate the acute effects of a single large dose of glycine on the human MMN in healthy subjects. Sixteen healthy male subjects participated in a double blind, placebo-controlled, crossover design in which each subject was tested under two acute treatment conditions separated by a 1-week washout period placebo and 0.8 g/kg glycine. The subjects were exposed to a duration-MMN paradigm with 50-ms standard tones (91%) and 100-ms deviant tones (9%). The results showed that glycine significantly attenuated duration MMN litude at frontal electrodes. There was no effect of glycine on MMN latencies or on litudes or latencies of N1, N2 and P3a. These findings suggest that an acute high dosage of glycine attenuates MMN in healthy controls, raising the possibility that optimal effects of glycine and other glycine agonists may depend on the integrity of the NMDA receptor system.
Publisher: American Psychiatric Association Publishing
Date: 10-2001
DOI: 10.1176/APPI.AJP.158.10.1687
Abstract: "Ecstasy," or 3,4-methylenedioxymeth hetamine (MDMA), causes long-term impairment to the serotonin (5-HT) system in rats, dogs, and nonhuman primates. 5-HT dysfunction has also been observed in human recreational users of the drug, but whether 5-HT dysfunction in humans is caused by MDMA has not been established, since dysfunction may have preceded MDMA exposure. This ambiguity about causation is particularly important in MDMA research, because 5-HT deficiency is a predictor of risky behavior. The 5-HT function of 22 long-term MDMA users was compared to that of 20 drug-naive comparison subjects and 19 cannabis users. 5-HT function was assessed with the intensity dependence paradigm, a tool that measures 5-HT-related attenuation of neural response to auditory stimuli (measured with EEG). Long-term MDMA users exhibited 5-HT dysfunction, relative to both cannabis users and drug-naive comparison subjects. This dysfunction was related to total MDMA consumption (after removing the effect of frequency of use) but not to frequency of use (after removing the effect of total consumption). These data show that 5-HT dysfunction occurs in MDMA users, is related to users' MDMA consumption, and is independent of cannabis use. The results do not suggest that self-medication explains this relationship, because the deficit was related to total MDMA consumption but not frequency of consumption. The results are thus consistent with the thesis that MDMA consumption causes 5-HT impairment in humans.
Publisher: Springer Science and Business Media LLC
Date: 06-12-2006
Abstract: Schizophrenia is associated with impairments of attentional control on classic experimental paradigms such as the Stroop task. However, at a basic level the neurochemical mechanisms that may be responsible for such impairments are poorly understood. In this study, we sought to investigate the influence of brain monoamine function on Stroop task performance in healthy participants using the established methods of acute dietary serotonin, dopamine, and combined monoamine depletion. The study was a double-blind placebo controlled design in which 12 healthy male participants completed the Stroop task under four acute treatment conditions: (a) balanced lacebo control, (b) acute tryptophan depletion, (c) acute tyrosine henylalanine depletion, and (d) acute tyrosine henylalanine/tryptophan depletion (combined monoamine depletion). Decreased Stroop interference indicating improved attentional control was observed after both tryptophan depletion and tyrosine henylalanine depletion, while there was no significant change in interference after combined monoamine depletion. Findings suggest that reduced tonic dopamine or serotonin activity within specific neural circuits (such as the striatum, anterior cingulate, or prefrontal cortex) may play a critical role in attentional control, possibly by improving gating of information via reducing noise in monoaminergic systems. These findings enhance our understanding of the neurochemical basis of attentional control and the possible cause of attentional control deficits in schizophrenia.
Publisher: Springer Science and Business Media LLC
Date: 23-03-2012
DOI: 10.1007/S10856-012-4622-6
Abstract: A new protocol, based on a modified replication method, is proposed to obtain bioactive glass scaffolds. The main feature of these s les, named "shell scaffolds", is their external surface that, like a compact and porous shell, provides both high permeability to fluids and mechanical support. In this work, two different scaffolds were prepared using the following slurry components: 59 % water, 29 % 45S5 Bioglass(®) and 12 % polyvinylic binder and 51 % water, 34 % 45S5 Bioglass(®), 10 % polyvinylic binder and 5 % polyethylene. All the proposed s les were characterized by a widespread microporosity and an interconnected macroporosity, with a total porosity of 80 % vol. After immersion in a simulated body fluid (SBF), the scaffolds showed strong ability to develop hydroxyapatite, enhanced by the high specific surface of the porous systems. Moreover preliminary biological evaluations suggested a promising role of the shell scaffolds for applications in bone tissue regeneration. As regards the mechanical behaviour, the shell scaffolds could be easily handled without damages, due to their resistant external surface. More specifically, they possessed suitable mechanical properties for bone regeneration, as proved by compression tests performed before and after immersion in SBF.
Publisher: Springer Science and Business Media LLC
Date: 02-09-2015
DOI: 10.1038/SREP13507
Abstract: The effect of electromagnetic field (EMF) exposures at the microwave (MW) frequency of 18 GHz, on four cocci, Planococcus maritimus KMM 3738, Staphylococcus aureus CIP 65.8 T , S. aureus ATCC 25923 and S. epidermidis ATCC 14990 T , was investigated. We demonstrate that exposing the bacteria to an EMF induced permeability in the bacterial membranes of all strains studied, as confirmed directly by transmission electron microscopy (TEM), and indirectly via the propidium iodide assay and the uptake of silica nanospheres. The cells remained permeable for at least nine minutes after EMF exposure. It was shown that all strains internalized 23.5 nm nanospheres, whereas the internalization of the 46.3 nm nanospheres differed amongst the bacterial strains ( S. epidermidis ATCC 14990 T ~ 0% Staphylococcus aureus CIP 65.8 T S. aureus ATCC 25923, ~40% Planococcus maritimus KMM 3738, ~80%). Cell viability experiments indicated that up to 84% of the cells exposed to the EMF remained viable. The morphology of the bacterial cells was not altered, as inferred from the scanning electron micrographs, however traces of leaked cytosolic fluids from the EMF exposed cells could be detected. EMF-induced permeabilization may represent an innovative, alternative cell permeability technique for applications in biomedical engineering, cell drug delivery and gene therapy.
Publisher: Elsevier BV
Date: 04-2012
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1RA05459G
Abstract: Membrane model systems capable of mimicking live cell membranes were used for the first time in studying the effects arising from electromagnetic fields (EMFs) of 18 GHz where membrane permeability was observed following exposure.
Publisher: Springer Science and Business Media LLC
Date: 24-07-2007
DOI: 10.1007/S00213-007-0870-4
Abstract: The loudness dependence of the auditory evoked Potential (LDAEP) has been suggested to be a putative marker of central serotonin function, with reported abnormalities in clinical disorders presumed to reflect serotonin dysfunction. Despite considerable research, very little is known about the LDAEP's sensitivity to other neurotransmitter systems. Given the role of N-methyl-D-aspartate (NMDA) receptors in modulating pyramidal cell activity in cortico-cortico and thalamo-cortical loops, we examined the effect of targeting the glycine modulatory site of the NMDA receptor with high-dose glycine on the LDAEP in healthy subjects. The study was a double-blind, placebo-controlled repeated-measures design in which 14 healthy participants were tested under two acute treatment conditions, placebo and oral glycine (0.8 g/kg). Changes in the litude of the N1/P2 at varying intensities (60, 70, 80, 90, 100 dB) were examined at C(Z). Compared to placebo, high-dose glycine induced a weaker LDAEP (a pronounced decrease in the slope of the N1/P2 with increasing tone loudness p < 0.02). While the exact mechanism responsible for the effects of glycine on the LDAEP are not known, the findings suggest an inhibitory effect in the cortex, possibly via activation of NMDA receptors on GABA interneurons or inhibitory glycine receptors. The findings add to the growing literature exhibiting modulation of the LDAEP by multiple neurochemical systems in addition to the serotonergic system.
Publisher: Frontiers Media SA
Date: 2013
Publisher: Frontiers Media SA
Date: 2013
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2020
DOI: 10.1097/HP.0000000000001252
Abstract: In this statement, the International Commission on Non-Ionizing Radiation Protection (ICNIRP) presents its principles for protection against adverse health effects from exposure to non-ionizing radiation. These are based upon the principles for protection against ionizing radiation of the International Commission for Radiological Protection (ICRP) in order to come to a comprehensive and consistent system of protection throughout the entire electromagnetic spectrum. The statement further contains information about ICNIRP and the processes it uses in setting exposure guidelines.
Publisher: Frontiers Media SA
Date: 2013
Publisher: Frontiers Media SA
Date: 2013
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2020
DOI: 10.1097/HP.0000000000001137
Abstract: Final results are now available from two large animal studies that investigated whether long-term exposure to radiofrequency (RF) electromagnetic fields (EMFs) associated with mobile (or cell) phones or base stations is carcinogenic these studies hale from the US National Toxicology Program (NTP) and the Ramazzini Institute in Italy, respectively. In both cases, the authors concluded that they had demonstrated that RF EMFs are carcinogenic in male rats but not in female rats or mice (NTP only). The International Commission on Non-Ionizing Radiation Protection (ICNIRP) has evaluated their methods and findings for potential information about the carcinogenicity of exposure to RF EMFs. We found that these studies had important strengths for ex le, both followed good laboratory practice (GLP), both used much larger numbers of animals than previous research, and both exposed animals over the whole of their lives. We also noted some major weaknesses, including a lack of blinding, difficulties interpreting statistical analyses due to the association between longer lifespans and tumor occurrence in the exposed rats (NTP only), and failure to account for chance. ICNIRP concluded that these substantial limitations preclude conclusions being drawn concerning RF EMFs and carcinogenesis.
Publisher: IEEE
Date: 08-2008
Publisher: Informa UK Limited
Date: 11-2012
DOI: 10.1080/15389588.2012.683118
Abstract: The present study compared the effects of a variety of mobile phone usage conditions to different levels of alcohol intoxication on simulated driving performance and psychomotor vigilance. Twelve healthy volunteers participated in a crossover design in which each participant completed a simulated driving task on 2 days, separated by a 1-week washout period. On the mobile phone day, participants performed the simulated driving task under each of 4 conditions: no phone usage, a hands-free naturalistic conversation, a hands-free cognitively demanding conversation, and texting. On the alcohol day, participants performed the simulated driving task at four different blood alcohol concentration (BAC) levels: 0.00, 0.04, 0.07, and 0.10. Driving performance was assessed by variables including time within target speed range, time spent speeding, braking reaction time, speed deviation, and lateral lane position deviation. In the BAC 0.07 and 0.10 alcohol conditions, participants spent less time in the target speed range and more time speeding and took longer to brake in the BAC 0.04, 0.07, and 0.10 than in the BAC 0.00 condition. In the mobile phone condition, participants took longer to brake in the natural hands-free conversation, cognitively demanding hands-free conversation and texting conditions and spent less time in the target speed range and more time speeding in the cognitively demanding, hands-free conversation, and texting conditions. When comparing the 2 conditions, the naturalistic conversation was comparable to the legally permissible BAC level (0.04), and the cognitively demanding and texting conversations were similar to the BAC 0.07 to 0.10 results. The findings of the current laboratory study suggest that very simple conversations on a mobile phone may not represent a significant driving risk (compared to legally permissible BAC levels), whereas cognitively demanding, hands-free conversation, and particularly texting represent significant risks to driving.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2020
DOI: 10.1097/HP.0000000000001259
Abstract: Since the original ICNIRP Statement was published in 2000, there have been significant improvements in the efficiency and radiance (i.e., optical radiation emission) of LEDs. The most important improvement is the development of ‘white’ LEDs that can be used as general lighting sources, which are more efficient than traditional lighting sources. LEDs emitting in the ultraviolet wavelength region have also become available and have made their way into consumer products. All these changes have led to a rise in concern for the safety of the optical radiation emissions from LEDs. Several in vitro and animal studies have been conducted, which indicate that blue and white LEDs can potentially cause retinal cell damage under high irradiance and lengthy exposure conditions. However, these studies cannot be directly extrapolated to normal exposure conditions for humans, and equivalent effects can also be caused by the optical radiation from other light sources under extreme exposure conditions. Acute damage to the human retina from typical exposure to blue or white LEDs has not been demonstrated. Concern for potential long-term effects, e.g. age-related macular degeneration (AMD), remains based on epidemiological studies indicating a link between high levels of exposure to sunlight and AMD. When evaluating the optical radiation safety of LEDs, it has now been established that published safety standards for l s, not lasers, should be applied. Thus far, the only clear, acute adverse health effects from LEDs are those due to temporal light modulation (including flicker). Glare can also create visual disturbances when LED light fixtures are not properly designed. Further research is needed on potential health effects from short- and long-term exposure to new and emerging lighting technologies.
Publisher: Elsevier BV
Date: 11-2020
Publisher: MDPI AG
Date: 28-04-2019
Abstract: There is now strong evidence that radiofrequency electromagnetic field (RF-EMF) exposure influences the human electroencephalogram (EEG). While effects on the alpha band of the resting EEG have been repeatedly shown, the mechanisms underlying that effect have not been established. The current study used well-controlled methods to assess the RF-EMF exposure effect on the EEG and determine whether that effect might be thermally mediated. Thirty-six healthy adults participated in a randomized, double-blind, counterbalanced provocation study. A water-perfusion suit (34 C) was worn throughout the study to negate environmental influences and stabilize skin temperature. Participants attended the laboratory on four occasions, the first being a calibration session and the three subsequent ones being exposure sessions. During each exposure session, EEG and skin temperature (8 sites) were recorded continuously during a baseline phase, and then during a 30 min exposure to a 920 MHz GSM-like signal (Sham, Low RF-EMF (1 W/kg) and High RF-EMF (2 W/kg)). Consistent with previous research, alpha EEG activity increased during the High exposure condition compared to the Sham condition. As a measure of thermoregulatory activation, finger temperature was found to be higher during both exposure conditions compared to the Sham condition, indicating for the first time that the effect on the EEG is accompanied by thermoregulatory changes and suggesting that the effect of RF-EMF on the EEG is consistent with a thermal mechanism.
Publisher: Wiley
Date: 10-2017
DOI: 10.1111/JSR.41_12619
Publisher: BMJ
Date: 25-08-2010
Abstract: Several studies have investigated the impact of mobile phone exposure on cognitive function in adults. However, children and adolescents are of special interest due to their developing nervous systems. Data were derived from the Australian Mobile Radiofrequency Phone Exposed Users' Study (MoRPhEUS) which comprised a baseline examination of year 7 students during 2005/2006 and a 1-year follow-up. Sociodemographic and exposure data were collected with a questionnaire. Cognitive functions were assessed with a computerised test battery and the Stroop Color-Word test. 236 students participated in both examinations. The proportion of mobile phone owners and the number of voice calls and short message services (SMS) per week increased from baseline to follow-up. Participants with more voice calls and SMS at baseline showed less reductions in response times over the 1-year period in various computerised tasks. Furthermore, those with increased voice calls and SMS exposure over the 1-year period showed changes in response time in a simple reaction and a working memory task. No associations were seen between mobile phone exposure and the Stroop test. We have observed that some changes in cognitive function, particularly in response time rather than accuracy, occurred with a latency period of 1 year and that some changes were associated with increased exposure. However, the increased exposure was mainly applied to those who had fewer voice calls and SMS at baseline, suggesting that these changes over time may relate to statistical regression to the mean, and not be the effect of mobile phone exposure.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2020
DOI: 10.1097/HP.0000000000001261
Abstract: Sources of low-frequency fields are widely found in modern society. All wires or devices carrying or using electricity generate extremely low frequency (ELF) electric fields (EFs) and magnetic fields (MFs), but they decline rapidly with distance to the source. High magnetic flux densities are usually found in the vicinity of power lines and close to equipment using strong electrical currents, but can also be found in buildings with unbalanced return currents, or indoor transformer stations. For decades, epidemiological as well as experimental studies have addressed possible health effects of exposure to ELF-MFs. The main goal of ICNIRP is to protect people and the environment from detrimental exposure to all forms of non-ionizing radiation (NIR). To this end, ICNIRP provides advice and guidance by developing and disseminating exposure guidelines based on the available scientific research. Research in the low-frequency range began more than 40 years ago, and there is now a large body of literature available on which ICNIRP set its protection guidelines. A review of the literature has been carried out to identify possible relevant knowledge gaps, and the aim of this statement is to describe data gaps in research that would, if addressed, assist ICNIRP in further developing guidelines and setting revised recommendations on limiting exposure to electric and magnetic fields. It is articulated in two parts: the main document, which reviews the science related to LF data gaps, and the annex, which explains the methodology used to identify the data gaps.
Publisher: Elsevier BV
Date: 10-2005
DOI: 10.1016/J.NEUROIMAGE.2005.05.022
Abstract: We assessed the usefulness of the P300 wave as endophenotype for schizophrenia by means of a meta-analysis of the literature as well as our own family study. Meta-analysis: We conducted a systematic search for articles published between 1983 and 2003 that reported P300 measures in non-psychotic relatives of schizophrenic patients and in healthy controls. Meta-regression analyses were performed using a random effects procedure. The pooled standardized effect size (PSES) was calculated as the difference between the means of the two groups ided by the common standard deviation. Local study: We examined the P300 wave with a standard two-tone oddball paradigm in 30 patients with schizophrenia, 40 non-psychotic relatives, and 40 controls using linear mixed models. Meta-analysis: We pooled 472 relatives and 513 controls. The P300 litude was significantly reduced in relatives (PSES = 0.61 95% CI: 0.30 to 0.91 P < 0.001). The P300 latency was significantly delayed in relatives (PSES of -0.50 95% CI: -0.88 to -0.13 P = 0.009]. Local study: The patients showed a trend for litude reductions (P = 0.06) and significant latency delays (P < 0.01). The relatives displayed normal litude but had significant latency delays (P = 0.01). The P300 litude and especially the P300 latency are promising alternative phenotypes for genetic research into schizophrenia.
Publisher: Wiley
Date: 11-04-2016
Publisher: Public Library of Science (PLoS)
Date: 08-07-2016
Publisher: Elsevier BV
Date: 10-2016
Publisher: Informa UK Limited
Date: 30-08-2017
DOI: 10.1080/15622975.2016.1208839
Abstract: Schizophrenia is characterised by significant episodic memory impairment that is thought to be related to problems with encoding, however the neuro-functional mechanisms underlying these deficits are not well understood. The present study used a subsequent recognition memory paradigm and event-related potentials (ERPs) to investigate temporal aspects of episodic memory encoding deficits in schizophrenia. Electroencephalographic data was recorded in 24 patients and 19 healthy controls whilst participants categorised single words as pleasant/unpleasant. ERPs were generated to subsequently recognised versus unrecognised words on the basis of a forced-choice recognition memory task. Subsequent memory effects were examined with the late positive component (LPP). Group differences in N1, P2, N400 and LPP were examined for words correctly recognised. Patients performed more poorly than controls on the recognition task. During encoding patients had significantly reduced N400 and LPP litudes than controls. LPP litude correlated with task performance however litudes did not differ between patients and controls as a function of subsequent memory. No significant differences in N1 or P2 litude or latency were observed. The present results indicate that early sensory processes are intact and dysfunctional higher order cognitive processes during encoding are contributing to episodic memory impairments in schizophrenia.
Publisher: Public Library of Science (PLoS)
Date: 23-04-2014
Publisher: Public Library of Science (PLoS)
Date: 12-09-2012
Publisher: Elsevier BV
Date: 2003
DOI: 10.1016/S0167-8760(02)00107-1
Abstract: Although slow waves of the electroencephalogram (EEG) have been associated with attentional processes, the functional significance of the alpha component in the EEG (8.1-12 Hz) remains uncertain. Conventionally, synchronisation in the alpha frequency range is taken to be a marker of cognitive inactivity, i.e. 'cortical idling'. However, it has been suggested that alpha may index the active inhibition of sensory information during internally directed attentional tasks such as mental imagery. More recently, this idea has been amended to encompass the notion of alpha synchronisation as a means of inhibition of non-task relevant cortical areas irrespective of the direction of attention. Here we test the adequacy of the one idling and two inhibition hypotheses about alpha. In two experiments we investigated the relation between alpha and internally vs. externally directed attention using mental imagery vs. sensory-intake paradigms. Results from both experiments showed a clear relationship between alpha and both attentional factors and increased task demands. At various scalp sites alpha litudes were greater during internally directed attention and during increased load, results incompatible with alpha reflecting cortical idling and more in keeping with suggestions of active inhibition necessary for internally driven mental operations.
Publisher: Elsevier BV
Date: 06-2002
DOI: 10.1016/S0165-1781(02)00104-X
Abstract: Difficulty inhibiting irrelevant information may play a central role in the aetiology of obsessive-compulsive disorder (OCD). The aim of the present study was to determine whether OCD subjects (n=20) exhibit deficits in behavioural and cognitive inhibition compared with a clinical control group diagnosed with panic disorder (n=20). All subjects were administered a Go/Nogo task (a measure of behavioural inhibition) and a Stroop test (a measure of cognitive inhibition). OCD subjects made more commission errors on the Go/Nogo task, and they made more errors and displayed longer reaction times on the interference trial of the Stroop task. Trends towards correlations were observed between OCD severity scores and Stroop reaction time, where the more severe the OCD symptoms the faster was the response. No correlations between clinical symptomatology or subject demographics and the Go/Nogo task were observed. It was demonstrated that OCD subjects exhibit deficits in behavioural and cognitive inhibition, which together may underlie the repetitive symptomatic behaviours of the disorder, such as compulsions and obsessions.
Publisher: Wiley
Date: 03-2013
DOI: 10.1111/RISA.12034
Abstract: In the past decade, growing public concern about novel technologies with uncertain potential long-term impacts on the environment and human health has moved risk policies toward a more precautionary approach. Focusing on mobile telephony, the effects of precautionary information on risk perception were analyzed. A pooled multinational experimental study based on a 5 × 2 × 2 factorial design was conducted in nine countries. The first factor refers to whether or not information on different types of precautionary measures was present, the second factor to the framing of the precautionary information, and the third factor to the order in which cell phones and base stations were rated by the study participants. The data analysis on the country level indicates different effects. The main hypothesis that informing about precautionary measures results in increased risk perceptions found only partial support in the data. The effects are weaker, both in terms of the effect size and the frequency of significant effects, across the various precautionary information formats used in the experiment. Nevertheless, our findings do not support the assumption that informing people about implemented precautionary measures will decrease public concerns.
Publisher: Springer Science and Business Media LLC
Date: 07-09-2017
DOI: 10.1038/S41598-017-11288-9
Abstract: The effect of red blood cells (RBC) exposed to an 18 GHz electromagnetic field (EMF) was studied. The results of this study demonstrated for the first time that exposure of RBCs to 18 GHz EMF has the capacity to induce nanospheres uptake in RBCs. The uptake of nanospheres (loading efficiency 96% and 46% for 23.5 and 46.3 nm nanospheres respectively), their presence and locality were confirmed using three independent techniques, namely scanning electron microscopy, confocal laser scanning microscopy and transmission electron microscopy. It appeared that 23.5 nm nanospheres were translocated through the membrane into the cytosol, while the 46.3 nm-nanospheres were mostly translocated through the phospholipid-cholesterol bilayer, with only some of these nanospheres passing the 2D cytoskeleton network. The nanospheres uptake increased by up to 12% with increasing temperature from 33 to 37 °C. The TEM analysis revealed that the nanospheres were engulfed by the cell membrane itself, and then translocated into the cytosol. It is believed that EMF-induced rotating water dipoles caused disturbance of the membrane, initiating its deformation and result in an enhanced degree of membrane trafficking via a quasi-exocytosis process.
Publisher: Springer Science and Business Media LLC
Date: 25-09-2020
Publisher: Elsevier BV
Date: 12-2012
DOI: 10.1016/J.JAD.2012.03.004
Abstract: In iduals with Major Depressive Disorder (MDD) tend to be more susceptible to distraction by negative emotional material than their non-depressed counterparts. This extends to an enhanced vulnerability to interference from mood-congruent stimuli during cognitive processing. The current study investigated the electrophysiological correlates of competing cognitive and emotional processing demands in MDD. Event-related alpha activity within the lower alpha 1 band was examined during the online information retention phase of a non-emotive WM task with extraneous emotional stimuli (positive, negative and neutral) presented as background images. EEG activity over posterior parietal cortex was compared between 15 acutely depressed and 16 never depressed right-handed women. A valence specific dissociation in lower alpha 1 activity was observed between the two groups, consistent with greater attentional resource allocation to positive distracters in control participants and to negative distracters in MDD participants. No group differences were seen when neutral distracters were displayed. These results demonstrate that activity within the lower alpha 1 band is sensitive to competing emotional and cognitive processing demands and highlight the importance of posterior parietal regions in depression-related susceptibility to affective distractibility during cognitive processing.
Publisher: Springer Science and Business Media LLC
Date: 25-01-2005
DOI: 10.1007/S00299-004-0896-6
Abstract: We have isolated a severe dwarf transposon (Ds) insertion mutant in rice (Oryza sativa L.), which could be differentiated early in the seedling stage by reduced shoot growth and dark green leaves, and later by severe dwarfism and failure to initiate flowering. These mutants, however, showed normal seed germination and root growth. One of the sequences flanking Ds, rescued from the mutant, was of a chromosome 4-located putative ent-kaurene synthase (KS) gene, encoding the enzyme catalyzing the second step of the gibberellin (GA) biosynthesis pathway. Dwarf mutants were always homozygous for this Ds insertion and no normal plants homozygous for this mutation were recovered in the segregating progeny, indicating that the Ds insertion mutation is recessive. As mutations in three recently reported rice GA-responsive dwarf mutant alleles and the dwarf mutation identified in this study mapped to the same locus, we designate the corresponding gene OsKS1. The osks1 mutant seedlings were responsive to exogenous gibberellin (GA3). OsKS1 transcripts of about 2.3 kb were detected in leaves and stem of wild-type plants, but not in germinating seeds or roots, suggesting that OsKS1 is not involved in germination or root growth. There are at least five OsKS1-like genes in the rice genome, four of which are also represented in rice expressed sequence tag (EST) databases. All OsKS1-like genes are transcribed with different expression patterns. ESTs corresponding to all six OsKS genes are represented in other cereal databases including barley, wheat and maize, suggesting that they are biologically active.
Publisher: Elsevier BV
Date: 09-2010
DOI: 10.1016/J.BRAINRESREV.2010.03.004
Abstract: Neuroimaging is fundamental to identifying quantifiable and objective biomarkers in symptomatic and pre-diagnostic Huntington's disease (HD). However, the challenge remains to find reliable biomarkers with high sensitivity and specificity that can be used to track the functional decline over time and test efficacy of therapeutic intervention. While many recent studies have focused on neuroimaging techniques based on brain hemodynamic activity, comparatively fewer have utilized electroencephalography (EEG) and event-related potentials (ERPs). This review aims to summarise and integrate key electroencephalographical findings from the last two decades in symptomatic and pre-diagnostic HD, in context with recent neuroimaging data, and to use this information to identify promising candidate markers for future research and clinical consideration.
Publisher: Elsevier BV
Date: 08-2002
DOI: 10.1016/S1388-2457(02)00147-5
Abstract: This study investigated electroencephalographic (EEG) differences between good and poor responders to methylphenidate in boys with the Inattentive type of Attention-Deficit/Hyperactivity Disorder (ADHD). Twenty good and 15 poor responders to methylphenidate, based on the results of a continuous performance task, and 35 age- and sex-matched control subjects, participated in this study. EEG was recorded from 21 sites during an eyes-closed resting condition and Fourier transformed to provide estimates for total power, and absolute and relative power in the delta, theta, alpha and beta bands, and for the theta/alpha and theta/beta ratios. EEG differences were found between the ADHD children and controls which were compatible with previous literature on the Inattentive type. Differences were also found between the good and poor responders to methylphenidate. Good responders had EEG profiles that suggested that they were more cortically hypoaroused than poor responders.
Publisher: Environmental Health Perspectives
Date: 19-09-2013
Publisher: Springer Science and Business Media LLC
Date: 19-06-2017
Publisher: Elsevier BV
Date: 08-2054
Publisher: Elsevier BV
Date: 11-2002
DOI: 10.1016/S0167-8760(02)00118-6
Abstract: A number of brain regions are associated with the subjective experience of pain. This study adds to our understanding of the neural mechanisms involved in pain by considering the relation between cortical oscillations in response to pain, with and without hypnosis and hypnotic analgesia, and the subjective experience of pain. Thirty-three subjects' neural responses (EEG) were measured during the 40-540 ms period following phasic electrical stimulations to the right hand, under control and hypnosis conditions. Resultant FFT litudes for frequencies ranging from 8 to 100 Hz were computed. These were grouped into 7 scalp topographies, and for each frequency, relations between these topographies and pain ratings, performance and stimulus intensity measures were assessed. Gamma activity (32-100 Hz) over prefrontal scalp sites predicted subject pain ratings in the control condition (r=0.50, P=0.004), and no other frequency/topography combination did. This relation was present in both high and low hypnotisable subjects and was independent of performance and stimulus intensity measures. This relation was unchanged by hypnosis in the low hypnotisable subjects but was not present in the highs during hypnosis, suggesting that hypnosis interferes with this pain/gamma relation. This study provides evidence for the role of gamma oscillations in the subjective experience of pain. Further, it is in keeping with the view that hypnosis involves the dissociation of prefrontal cortex from other neural functions.
Publisher: Wiley
Date: 03-2011
DOI: 10.1002/HUP.1187
Abstract: The loudness dependence of the auditory evoked potential (LDAEP) has been suggested as a marker of the serotonin system, although studies directly examining the relationship between acute changes in serotonin and the LDAEP have been inconsistent. Given the reported sex dichotomy in serotonin neurotransmission, this study examined if there are sex differences in the LDAEP. Data from 65 healthy participants from four independent studies were pooled, and their N1/P2 slopes were quantified. Mean N1/P2 slopes for female participants were higher than those for male participants (p < 0.0001). These findings suggest that the LDAEP is modulated by sex potentially because of differences in serotonergic neurotransmission, and these differences may account for some of the inconsistent findings linking serotonin function and LDAEP.
Publisher: Elsevier BV
Date: 03-2003
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.IJPSYCHO.2017.12.008
Abstract: Recent research has provided evidence to suggest that emotional stimuli may interfere with response inhibition, due to automatic capture of attention. Whilst previous studies have provided data regarding changes to event-related potentials (ERPs) in emotional Go/NoGo tasks, few studies to-date have utilized an emotional stop signal task (SST). Thirty-five participants were included in the study 21 healthy controls and 14 depressed. An indirect emotional SST was employed, which consisted of the presentation of neutral, negative or positive visual images. The primary two-choice reaction time task required responding to frame colour (blue or green), whilst in 33% of trials an auditory stop signal was presented, with stop signal delay adjusted according to an adaptive tracking procedure. ERPs associated with both the primary visual task and the auditory SST were analysed using temporal principle components analysis (tPCA). In the primary task, reaction times were found to be slower for negative compared to neutral images. Stop signal reaction time (SSRT) was not found to be affected by image category or depression status. However, the NoGo-N2 component was found to be reduced for positive images, whilst the NoGo-P3 component was reduced for both positive and negative images in comparison to neutral images in the stop signal task. This effect was found to be enhanced for the depressed participants, indicating that inhibitory processing in the presence of positive stimuli may be inhibited to a greater extent in depressed in iduals than in healthy controls. These findings provide further evidence for the ability of emotional valence and major depressive disorder to influence inhibitory processing.
Publisher: Elsevier BV
Date: 12-2010
Publisher: American Society for Microbiology
Date: 05-2011
DOI: 10.1128/AEM.01899-10
Abstract: The present study investigated the effects of microwave (MW) radiation applied under a sublethal temperature on Escherichia coli . The experiments were conducted at a frequency of 18 GHz and at a temperature below 40°C to avoid the thermal degradation of bacterial cells during exposure. The absorbed power was calculated to be 1,500 kW/m 3 , and the electric field was determined to be 300 V/m. Both values were theoretically confirmed using CST Microwave Studio 3D Electromagnetic Simulation Software. As a negative control, E. coli cells were also thermally heated to temperatures up to 40°C using Peltier plate heating. Scanning electron microscopy (SEM) analysis performed immediately after MW exposure revealed that the E. coli cells exhibited a cell morphology significantly different from that of the negative controls. This MW effect, however, appeared to be temporary, as following a further 10-min elapsed period, the cell morphology appeared to revert to a state that was identical to that of the untreated controls. Confocal laser scanning microscopy (CLSM) revealed that fluorescein isothiocyanate (FITC)-conjugated dextran (150 kDa) was taken up by the MW-treated cells, suggesting that pores had formed within the cell membrane. Cell viability experiments revealed that the MW treatment was not bactericidal, since 88% of the cells were recovered after radiation. It is proposed that one of the effects of exposing E. coli cells to MW radiation under sublethal temperature conditions is that the cell surface undergoes a modification that is electrokinetic in nature, resulting in a reversible MW-induced poration of the cell membrane.
Publisher: Mary Ann Liebert Inc
Date: 05-2018
Publisher: Wiley
Date: 07-2008
DOI: 10.1111/J.1469-8986.2008.00642.X
Abstract: This article approaches the problem of EOG artifact correction using one EOG channel from a biophysical point of view. It shows that recordings from one EOG channel are sufficient to correct artifacts from one-dimensional eye movements not exceeding 30 degrees . We prove that the subtraction method "corrected EEG=measured EEG-backward propagation * measured EOG" yields the uncorrupted EEG trace up to scaling despite possible influences of forward propagation. Further, a special calibration paradigm (aligned artifact average, AAA) is investigated, and algorithms are presented to calculate the exact backward propagation. Experimental results from 13 subjects are shown, supporting the theoretical prediction of optimal correction.
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.ENVRES.2018.12.058
Abstract: Exposure to far-field radiofrequency electromagnetic fields (RF-EMF) has raised public concerns in recent decades. However, it is not known if in iduals' perception towards the health risks of RF-EMF is dependent on their knowledge of the objectively measured personal RF-EMF exposure levels. This pilot study aimed to demonstrate the feasibility of objectively measuring personal RF-EMF exposure from mobile phone base stations (MPBS) and to determine if the risk perception of people to the potential health risk of exposure to RF-EMF from MPBS is dependent on their knowledge of personal RF-EMF exposure levels. An experimental study was conducted in 383 adults, recruited in Melbourne, Australia. Participants were randomized to one of the three groups: 1) basic information group who were provided with basic information about RF-EMF to read prior to completing a risk perception assessment questionnaire 2) precautionary group who were provided with an information pack which included precautionary messages and 3) personal exposure measurement group who were provided with a summary of their quantitative RF-EMF exposure from MPBS. The same basic information about RF-EMF was also given to the precautionary and personal exposure measurement groups. Participants had a mean (± SD) age of 36.9 ± 12.5 years 66.7% were women. Overall, 44.1% had noticed an MPBS in their neighbourhood. The mean (SD) values (from 1 to 7) for risk perceptions to RF-EMF from MPBS were 4.02 (1.67) for basic information, 3.82 (1.62) for precautionary messages, and 3.97 (1.72) for the personal exposure measurement groups. These differences were not statistically significant. Nevertheless, the personal exposure measurement group were more confident that they could protect themselves from RF-EMF than the precautionary or basic information groups. Our findings suggest that providing people with personal RF-EMF exposure measurements may not affect their perceived risk from MPBS, but increase their confidence in protecting themselves.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2007
Publisher: Elsevier BV
Date: 06-2016
DOI: 10.1016/J.CLINPH.2016.03.013
Abstract: P50 suppression refers to the P50 ERP litude-reduction to the second (S2) relative to the first (S1) of identical brief auditory stimuli (SOA=500ms). Its reduction in schizophrenia is argued to represent impaired inhibitory input (II) mechanisms. Enhancing attention enhances II functionality (reducing S2P50 litude and increasing P50 difference) in healthy subjects. We determined whether the effect of attention on P50 suppression differs between schizophrenia patients (SCZ) and controls (CON) and thus is a confound in P50 schizophrenia research. We manipulated the direction of attention (attention, non-attention) in 21 SCZ and 18 CON in the P50 suppression task. Directing attention towards stimulus pairs (versus non-attention) increased P50 suppression (P50 difference). This effect differed between groups, with attention increasing S1P50, reducing S2P50 and increasing P50 suppression (P50 difference and reducing P50 ratio) in CON only. No group differences were found for P50 difference or ratio. Attention is a confound in schizophrenia P50 research and thus should be carefully controlled. When attention was controlled, P50 group differences were not found. The SCZ-CON P50 difference reported in the literature may be related to uncontrolled attention (and not impaired P50 suppression per se).
Publisher: Wiley
Date: 10-11-2018
DOI: 10.1002/BEM.22095
Abstract: The etiology of Idiopathic Environmental Intolerance attributed to Electromagnetic Fields (IEI-EMF) is controversial. While the majority of studies have indicated that there is no relationship between EMF exposure and symptoms reported by IEI-EMF sufferers, concerns about methodological issues have been raised. Addressing these concerns, the present experiment was designed as a series of in idual case studies to determine whether there is a relationship between radiofrequency-electromagnetic field (RF-EMF) exposure and an IEI-EMF in idual's self-reported symptoms. Three participants aged 44-64 were tested during a series of sham and active exposure trials (2 open-label trials 12 randomized, double-blind, counterbalanced trials), where symptom severity and exposure detection were scored using 100 mm visual analogue scales. The RF-EMF exposure was a 902-928 MHz spread spectrum digitally modulated signal with an average radiated power output of 1 W (0.3 W/m
Publisher: Springer Science and Business Media LLC
Date: 23-03-2021
DOI: 10.1007/S40201-021-00636-7
Abstract: The impact of providing people with an objectively measured personal radiofrequency electromagnetic fields (RF-EMF) exposure information on the risk perception of people is not well understood. We conducted an experimental study, among three groups of participants, to investigate the risk perception of people towards RF-EMF from Wi-Fi sources (ISM 2.4 GHz) by providing participants with either basic text, precautionary information, or a summary of their personal RF-EMF exposure measurement levels. Participants provided with personal RF-EMF exposure measurement information were more confident in protecting themselves from RF-EMF exposure, compared to those provided with only basic information. Nonetheless, neither the exposure perception nor the risk perception of people to Wi-Fi related RF-EMF differed by the type of information provided. The measured Wi-Fi signal levels were far below international exposure limits. Furthermore, self-rated levels of personal RF-EMF exposure perception were not associated with objectively measured RF-EMF exposure levels. Providing people with objectively measured information may help them build confidence in protecting themselves from Wi-Fi related RF-EMF exposure.
Publisher: Oxford University Press (OUP)
Date: 09-2008
Publisher: Wiley
Date: 2008
DOI: 10.1002/BEM.20352
Abstract: Mobile phones (MP) emit low-level electromagnetic fields that have been reported to affect neural function in humans however, demonstrations of such effects have not been conclusive. The purpose of the present study was to test one of the strongest findings in the literature that of increased "alpha" power in response to MP-type radiation. Healthy participants (N = 120) were tested using a double-blind counterbalanced crossover design, with each receiving a 30-min Active and a 30-min Sham Exposure 1 week apart, while electroencephalogram (EEG) data were recorded. Resting alpha power (8-12 Hz) was then derived as a function of time, for periods both during and following exposure. Non-parametric analyses were employed as data could not be normalized. Previous reports of an overall alpha power enhancement during the MP exposure were confirmed (relative to Sham), with this effect larger at ipsilateral than contralateral sites over posterior regions. No overall change to alpha power was observed following exposure cessation however, there was less alpha power contralateral to the exposure source during this period (relative to ipsilateral). Employing a strong methodology, the current findings support previous research that has reported an effect of MP exposure on EEG alpha power.
Publisher: Springer Science and Business Media LLC
Date: 18-07-2005
Publisher: Informa UK Limited
Date: 16-05-2017
DOI: 10.1080/13825585.2017.1325827
Abstract: Aging and depression have been found to be associated with poorer performance in mnemonic discrimination. In the current study, a two-response format mnemonic similarity test, Cognitive Drug Research MST, was used to compare these effects. Seventy-six participants were tested with 52 participants in the young group, aged 18-35 years, and 24 participants in the elderly group, aged 55 years or older. Twenty-two young participants and 10 elderly participants met DSM-IV criteria for MDD or dysthymia. Age-related deficits were found for lure identification and speed of response. Differences in speed of responses to lure images were found for younger depressed participants, and depressive symptom severity was found to be negatively associated with lure identification accuracy in the elderly. These findings may be viewed as putative behavioral correlates of decreased pattern separation ability, which may be indicative of altered hippoc al neurogenesis in aging and depression.
Publisher: Elsevier BV
Date: 09-2013
DOI: 10.1016/J.IJPSYCHO.2013.04.015
Abstract: Chronic cannabis use has been associated with neurocognitive deficits, alterations in brain structure and function, and with psychosis. This study investigated the effects of chronic cannabis use on P50 sensory-gating in regular users, and explored the association between sensory gating, cannabis use history and the development of psychotic-like symptoms. Twenty controls and 21 regular cannabis users completed a P50 paired-click (S1 and S2) paradigm with an inter-pair interval of 9s. The groups were compared on P50 litude to S1 and S2, P50 ratio (S2/S1) and P50 difference score (S1-S2). While cannabis users overall did not differ from controls on P50 measures, prolonged duration of regular use was associated with greater impairment in sensory gating as indexed by both P50 ratio and difference scores (including after controlling for tobacco use). Long-term cannabis users were found to have worse sensory gating ratios and difference scores compared to short-term users and controls. P50 metrics did not correlate significantly with any measure of psychotic-like symptoms in cannabis users. These results suggest that prolonged exposure to cannabis results in impaired P50 sensory-gating in long-term cannabis users. While it is possible that these deficits may have pre-dated cannabis use and reflect a vulnerability to cannabis use, their association with increasing years of cannabis use suggests that this is not the case. Impaired P50 sensory-gating ratios have also been reported in patients with schizophrenia and may indicate a similar underlying pathology.
Publisher: Springer Science and Business Media LLC
Date: 25-03-2017
DOI: 10.1007/S00421-017-3592-2
Abstract: Many researchers have addressed the potential effects of hyperthermia and dehydration on cognition, often revealing contradictory outcomes. A possible reason for this inconsistency is that experiments may have been inadequately designed for such effects. In this study, the impact of hyperthermia, dehydration and their combination on cognition were evaluated in eight young males, after accounting for a range of experimental limitations. Passive heating and thermal cl ing at two mean body temperatures (36.5, 38.5 °C) were performed under three hydration states (euhydrated, 3 and 5% dehydrated) to assess their effects on difficulty-matched working memory and visual perception tasks, and on a difficulty manipulated perceptual task. Data were analysed according to signal detection theory to isolate changes in response sensitivity, bias and speed. Neither moderate hyperthermia (P = 0.141) nor dehydration (P > 0.604) modified response sensitivity, nor did they significantly interact (P > 0.698). Therefore, the ability to distinguish correct from incorrect responses was unaffected. Nevertheless, hyperthermia, but not dehydration (P = 0.301), reduced the response bias (-0.08 versus 2.2 [normothermia] P = 0.010) and reaction time (mean reduction 49 ms P < 0.001), eliciting more liberal and faster responses (P = 0.010). Response bias was reduced for the memory relative to the perceptual task (P = 0.037), and this effect was enhanced during hyperthermia (P = 0.031). These observations imply that, once potentially confounding influences were controlled, moderate hyperthermia, significant dehydration and their combined effects had insufficient impact to impair cognition within the memory and perceptual domains tested. Nonetheless, moderate hyperthermia elicited more liberal and rapid responses.
Publisher: Wiley
Date: 23-07-2019
DOI: 10.1002/BEM.22209
Abstract: It is well known that applying transcranial alternating current stimulation (tACS) to the scalp can generate artefactual visual perceptions of flashing or shimmering light known as phosphenes. The thresholds for generating these phosphenes have been used by international standards bodies to provide conservative estimates of the field strength required to interfere with human neural functioning and set safety limits accordingly. However, the precise relationship between electric currents and phosphene perception thresholds remains uncertain. The present study used tACS to systematically investigate the effects of the location and the frequency of stimulation on phosphene perception thresholds. These thresholds were obtained from 24 participants using a within-subject design as a function of scalp stimulation sites (FPz-Cz versus Oz-Cz) and stimulation frequency (2-30 Hz in steps of 2 Hz). Phosphene perception thresholds were consistently lower for FPz-Cz stimulation, and regardless of tACS location were lowest for 16 Hz stimulation. Threshold variation between participants was very small, which is meaningful when setting standards based on phosphenes. Bioelectromagnetics. 2019 :365-374. © 2019 Bioelectromagnetics Society.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2017
Publisher: Elsevier BV
Date: 12-2010
DOI: 10.1016/J.JAD.2010.05.022
Abstract: EEG studies examining 'resting' state (i.e. non-task) state brain activity in major depressive disorder (MDD) have reported numerous abnormalities within the alpha bandwidth. These findings are discussed extensively within affective disorders literature but their relationship to functional aspects of depressive psychopathology remains unclear. Investigating alpha modulation during active cognitive processing may provide a more targeted means of relating aberrant alpha activity to specific aspects of depression symptomatology. Alpha activity is reliably modulated during working memory (WM) processing and WM impairments are a common neuropsychological consequence of MDD. Moreover, it has been suggested that alpha activity reflects internally mediated inhibitory process and attenuated inhibition has been suggested to contribute to WM inefficacy. The current investigation examined whether alpha was modulated differently in MDD participants during WM processing and whether the pattern of alpha activity was consistent with impairments in inhibitory processes. Event related synchronisation (ERS) within the upper alpha band over the retention interval of a modified Sternberg WM task was examined in 15 acutely depressed and 15 never depressed right-handed female participants. MDD participants displayed greater upper alpha ERS than controls during the online information maintenance component of WM processing. This was evident over left, but not right, parieto-occipital cortex. The results are consistent with increased inhibition of extraneous material during WM processing in depression. This may reflect a neurobiological compensation strategy whereby additional neural resources are required to achieve comparable performance accuracy during effortful cognitive processing in MDD.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2016
Publisher: Springer Science and Business Media LLC
Date: 25-09-2020
Publisher: Elsevier BV
Date: 06-2002
DOI: 10.1016/S0167-8760(01)00201-X
Abstract: An important method for removing the effect of ocular artefact from the EEG is 'EOG correction'. This method estimates the proportion of ocular artefact that is in the EEG, and removes it by subtraction. To date, EOG correction research has focused on problems relating to the estimation of the correction coefficients. Using both mathematical rationale and empirical data, this paper addresses issues relating to the subtraction phase, such as the magnitude of error that can be expected due to EOG correction. Using ERP methodology, principal component and regression analyses, it is shown that the N1P2 complex propagates forward to the horizontal and radial (but not vertical) electrooculograms (EOG), and it is shown mathematically that this will result in EOG-correction error. Assuming an accurate estimate of ocular contamination of the EEG, maximal subtraction-phase error of the N1P2 complex was found to be a prefrontal attenuation of 15-22%, decreasing to central and occipital enhancements of 3-4% and 13-14%, respectively. The magnitude of this subtraction-phase error is compared to between-subject ERP variability and to error associated with EOG rejection (omitting data contaminated by ocular artefact). It is argued that such EOG correction error is small relative to both artefact rejection procedures and to normal variability found in ERP studies, and that it is less pernicious than artefact rejection procedures.
Publisher: Wiley
Date: 2008
DOI: 10.1002/BEM.20380
Publisher: Elsevier BV
Date: 12-1998
DOI: 10.1016/S0013-4694(98)00087-X
Abstract: In the field of EOG correction, discrepancies have been found between the propagation rates for different types and frequencies of eye movement. However, Croft and Barry demonstrated that these differences can be explained by the affect of EOG magnitude on the correction procedure (Croft, R.J. and Barry, R.J. EOG correction: a new perspective. Electroenceph. clin. Neurophysiol., 1998, 107: 387-394). This study utilized a new 'aligned-artifact average' technique (AAA) to examine whether propagation is constant across eye movement types and frequencies, and tested the AAA as an EOG correction tool. Two experiments manipulated interference levels in real data sets to determine if interference affected propagation coefficients (Bs). The third tested real data for the effect of forward propagation of eye movement related neural potentials on Bs, and the fourth utilized computer simulations to assess the effectiveness of the new AAA correction procedure. Interference was found to inflate B at low EOG litude, and its removal removed B variation and inflation. The forward propagation of eye movement related neural potentials had very little effect on B. The AAA procedure produced near perfect corrections of the simulated data, superior to a comparison method. EOG propagation is constant across eye movement types and frequencies, and thus only one correction coefficient should be calculated and applied to data. The AAA method provides a more accurate correction and makes possible, for the first time, the adequate correction of posterior sites.
Publisher: Springer Science and Business Media LLC
Date: 09-08-2012
DOI: 10.1007/S00253-012-4339-Y
Abstract: The aim of the present review was to evaluate the literature suggesting that consideration be given to the existence of specific microwave (MW) effects on prokaryotic microorganisms that is, effects on organisms that cannot be explained by virtue of temperature increases alone. This review considered a range of the reported effects on cellular components including membranes, proteins, enzyme activity as well as cell death. It is concluded that the attribution of such effects to non-thermal mechanisms is not justified due to poor control protocols and because of the possibility that an unmeasurable thermal force, relating to instantaneous temperature (T (i)) that occurs during MW processing, has not been taken into account. However, due to this lack of control over T (i), it also follows that it cannot be concluded that these effects are not 'non-thermal'. Due to this ambiguity, it is proposed that internal 'micro'-thermal effects may occur that are specific to MW radiation, given its inherent unusual energy deposition patterning.
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.BRAT.2008.02.006
Abstract: The study aimed to address a significant gap in the literature on inhibition impairments in OCD, by concurrently studying facilitation and inhibition processes and the effect of threat on these twin mechanisms. Participants were 20 persons with symptomatic OCD, 11 with remitted OCD, 20 with panic disorder and 20 normal control participants. Participants were required to respond to words that were either neutral or personally threatening, which during an immediately preceding trail, were responded to as targets (facilitation) or inhibited as non-targets (inhibition). OCD participants displayed greater facilitation and reduced inhibition, differences that were related to their diagnostic status but unrelated to symptomatic status. Threat had no effect on facilitation, but exacerbated inhibition problems in the symptomatic OCD and panic groups. This research suggests that underlying differences in both facilitation and inhibition, combined with influences of activated threat-schema on inhibition may play a role in the development and maintenance of OCD.
Publisher: Routledge
Date: 14-06-2018
Publisher: Springer Science and Business Media LLC
Date: 10-12-2009
DOI: 10.1007/S00213-009-1723-0
Abstract: Schizophrenia is commonly associated with impairments in pre-attentive change detection, as represented by reduced mismatch negativity (MMN). While the neurochemical basis of MMN has been linked to N-methyl-D: -aspartic acid (NMDA) receptor function, the roles of the dopaminergic and/or the serotonergic systems are not fully explored in humans. The aim of the present study was to investigate the effects of acutely depleting dopamine (DA) and serotonin (5-hydroxytryptamine, 5-HT) alone or simultaneously by depleting their amino acid precursors on MMN in healthy participants. Sixteen healthy male subjects participated in a double-blind, placebo-controlled, cross-over design in which each subject's duration MMN was assessed under four acute treatment conditions separated by a 5-day washout period: balanced amino acid control (no depletion), tyrosine henylalanine depletion (to reduce DA neurotransmission), tryptophan depletion (to reduce 5-HT neurotransmission) and tryptophan/tyrosine henylalanine depletion (to reduce DA and 5-HT neurotransmission simultaneously). Acute depletion of either DA and 5-HT alone or simultaneously had no effect on MMN. These findings suggest that modulation of the dopaminergic and serotonergic systems acutely does not lead to changes in MMN.
Publisher: Elsevier BV
Date: 02-2003
DOI: 10.1016/S0167-8760(02)00119-8
Abstract: Stimulant medications are the most commonly-used treatments for Attention-Deficit/Hyperactivity Disorder (ADHD) in North America and Australia, although it is still not entirely known how these medications work. This study investigated the effects of stimulant medications on the EEG of children with the Inattentive type of ADHD. An initial EEG was recorded during an eyes-closed resting condition and Fourier transformed to provide absolute and relative power estimates for the delta, theta, alpha and beta bands. Theta/alpha and theta/beta ratios were also calculated. Subjects were placed on a 6-month trial of a stimulant and a second EEG was recorded at the end of the trial. Subjects were included in this study only if they showed a good clinical response during the trial. The unmedicated ADHD group had significantly greater absolute and relative theta, less relative alpha, and higher theta/alpha and theta/beta ratios than the control group. The stimulant medications resulted in a normalisation of the EEG, with changes in the theta, alpha and beta bands being most evident. These results suggest that stimulants act to increase cortical arousal in children with ADHD, normalising their EEG.
Publisher: Elsevier BV
Date: 11-2004
DOI: 10.1016/J.CLINPH.2004.06.004
Abstract: We aimed to examine the relation between the phase of electroencephalogram (EEG) alpha activity at stimulus onset and event-related potentials (ERPs) in a fixed-inter-stimulus interval auditory 'oddball' task, using a novel conceptualisation of orthogonal phase effects (cortical negativity versus positivity, negative driving versus positive driving, waxing versus waning). EEG responses to button-press targets, from 14 subjects presented with 4 blocks of 150 stimuli (50% target probability), were examined. Pre-stimulus alpha activity (8-13 Hz) at Pz was assessed for each trial by digital filtering of the EEG. The alpha cycle at Pz, starting from a negative-going zero crossing, was used to sort trials into 4 phases, for which ERPs were derived from both the filtered and unfiltered EEG activity at Fz, Cz, and Pz. Preferred brain states in this paradigm were indicated by an 8% greater occurrence of negative driving than positive driving, and a 33% greater occurrence of waxing than waning phases. Negative driving phases were associated with increased N1 latencies and decreased N2 litudes. Latencies of N1 and P2 were reduced in waxing phases. These reflected systematic changes in alpha frequency and litude at stimulus onset. In a fixed-inter-stimulus interval paradigm, component frequencies of the EEG are dynamically adjusted in order to provide brain states at the moment of stimulus presentation which differentially affect the EEG correlates of stimulus processing. The results add to our understanding of the genesis of the ERP, indicating the importance of the dynamic interplay between instantaneous EEG activity and stimulus processing reflected in the ERP.
Publisher: MDPI AG
Date: 08-06-2017
Publisher: Wiley
Date: 13-01-2021
DOI: 10.1002/BEM.22317
Publisher: Springer Science and Business Media LLC
Date: 09-08-2006
DOI: 10.1007/S00213-006-0501-5
Abstract: The Loudness Dependence of the Auditory Evoked Potential (LDAEP) has been suggested as a reliable measure of central serotonin function in humans however, its specificity for the serotonin system remains a topic of debate, with possible modulation of this purported serotonin marker by other neurotransmitters, including dopamine. We examined the effect of dopaminergic modulation on the LDAEP using the D1/D2/D3 dopamine receptor agonist pergolide and the D2/D3 agonist bromocriptine. The study was a double-blind, placebo-controlled repeated-measures design in which healthy participants were tested under three acute treatment conditions: placebo, bromocriptine (2.5 mg), and pergolide (0.1 mg). Changes in the litude of the N1/P2 at intensities (60, 70, 80, 90, and 100 dB) were examined at C Z. Acute stimulation of D1/D2/D3 receptors with pergolide and D2/D3 receptors with bromocriptine in comparison with placebo had no effect on the LDAEP. These findings indicate that acute stimulation of dopamine D1, D2, and D3 receptors does not modulate the LDAEP in humans. Although the findings suggest that the LDAEP may not be modulated by acute changes in dopamine neurotransmission, further studies are needed to fully characterize its dopaminergic sensitivity.
Publisher: Wiley
Date: 05-0007
Abstract: The P3(00) is an electrophysiological index of neural processing that varies with such stimulus parameters as interstimulus interval (ISI) and target probability, with a common view being that it reflects an endogenous form of memory update. Building on previous research, we argue that relations between P3 litude and both ISI and probability may be attributable to the target-to-target interval (TTI). Employing between-subject (Experiment 1 N = 24) and within-subject (Experiment 2 N = 10) designs, the present paper addresses this by testing subjects on a standard two-tone auditory oddball task as well as a one-tone task. In both studies, P3 litude increased and latency decreased linearly with TTI, and these relations were relatively unaffected by ISI or probability. This suggests that ISI and probability per se do not independently affect P3 litude, and that TTI offers a strong explanation of the reported relations between P3 litude and both ISI and probability.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2022
Publisher: Mary Ann Liebert Inc
Date: 09-2009
DOI: 10.1089/TEN.TEC.2008.0350
Abstract: Bioprosthetic valves created from chemically treated natural tissues such as bovine pericardial biomaterial are used as heart valve scaffolds. Methods currently available for sterilization of biomaterial for transplantation include the application of gamma radiation and chemical sterilants. These techniques, however, can be problematic because they can be expensive and lead to a reduction in tissue integrity. Therefore, improved techniques are needed that are cost effective and do not disrupt the physical properties, functionality, and lifespan of the valvular leaflets. This study examined a novel technique using nonthermal microwave radiation that could lead to the inactivation of bacteria in bovine pericardial biomaterial without compromising valve durability. Two common pathogenic species of bacteria, Escherichia coli and Staphylococcus aureus, were used as test microorganisms. Optimized microwave parameters were used to determine whether inactivation of pathogenic bacteria from bovine pericardium could be achieved. In addition, the effect of microwave sterilization on tissue integrity was examined. The mechanical properties (assessed using dynamic mechanical analysis) and tensile strength testing (using a Universal Tensile Tester) as well as thermal analysis (using thermogravimetric analysis and differential scanning calorimetry) indicated that microwave sterilization did not compromise the functionality of bovine pericardial biomaterial. Scanning electron microscopy imaging and cytotoxicity testing also confirmed that the structure and biocompatibility of transplant biomaterial remained unaltered after the sterilization process. Results from the application of this new microwave (MW) sterilization technique to bovine pericardium showed that near-complete inactivation of the contaminant bacteria was achieved. It is concluded that nonthermal inactivation of pathogenic bacteria from bovine pericardial biomaterial could be achieved using microwave radiation.
Publisher: Wiley
Date: 2006
DOI: 10.1002/HUP.740
Abstract: The loudness dependence of the auditory evoked potential (LDAEP) has been suggested as a reliable measure of central serotonin function in humans. The most convincing evidence for a direct relationship between serotonergic function and LDAEP to date has come from animal studies, while evidence in humans has been circumstantial and inconsistent. In the current study, we examine the direct effect of serotonergic modulation with the selective serotonin reuptake inhibitor (SSRI) citalopram on the LDAEP. The study was a double-blind placebo controlled design in which healthy participants were tested under two acute treatment conditions: placebo and citalopram (20 mg). Enhancement of serotonin function with citalopram in comparison to placebo decreased the slope of the LDAEP (i.e. weaker LDAEP). The findings provide direct evidence in humans, of a relationship between central serotonin function and the LDAEP, supporting findings previously observed in animals and clinical populations. Together the results provide further support for the validity of the LDAEP as a non-invasive in vivo measure of central serotonin function in humans.
Publisher: Elsevier BV
Date: 02-2011
DOI: 10.1016/J.IJPSYCHO.2010.10.008
Abstract: A group of methods that are employed for removing ocular artifact from the electroencephalogram (EEG) is referred to as electrooculogram (EOG) correction methods. These use least-square linear regression, and the relative success of these is yet to be established. Improving on previous EOG correction validation studies, we present a new validation technique (with greater face validity) and use it to compare four commonly employed EOG correction methods. Data consisted of ERP traces to auditory stimuli that were embedded in up, down, left and right eye movements (EMs), recorded from 24 subjects. A 'Peak Difference' validation measure was employed, which determined the magnitude of the difference of two auditory N100 peaks (those associated with EMs with opposing polarities). All correction methods produced data that was better than not correcting at all. EOG correction methods that accounted for vertical EM, horizontal EM and blink artifact separately using separate EOG channels, produced the best corrections, with some further advantage in methods that enhanced signal (EOG) to noise (EEG) ratios when calculating correction coefficients.
Publisher: Oxford University Press (OUP)
Date: 05-2013
DOI: 10.1017/S1461145712000752
Abstract: Episodic memory deficits are a core feature of neurodegenerative disorders. Muscarinic M1 receptors play a critical role in modulating learning and memory and are highly expressed in the hippoc us. We examined the effect of GSK1034702, a potent M1 receptor allosteric agonist, on cognitive function, and in particular episodic memory, in healthy smokers using the nicotine abstinence model of cognitive dysfunction. The study utilized a randomized, double-blind, placebo-controlled, cross-over design in which 20 male nicotine abstained smokers were tested following single doses of placebo, 4 and 8 mg GSK1034702. Compared to the baseline (nicotine on-state), nicotine abstinence showed statistical significance in reducing immediate (p=0.019) and delayed (p=0.02) recall. GSK1034702 (8 mg) significantly attenuated (i.e. improved) immediate recall (p=0.014) but not delayed recall. None of the other cognitive domains was modulated by either nicotine abstinence or GSK1034702. These findings suggest that stimulating M1 receptor mediated neurotransmission in humans with GSK1034702 improves memory encoding potentially by modulating hippoc al function. Hence, selective M1 receptor allosteric agonists may have therapeutic benefits in disorders of impaired learning including Alzheimer's disease.
Publisher: Elsevier BV
Date: 12-1998
DOI: 10.1016/S0013-4694(98)00086-8
Abstract: In the field of EOG correction, discrepancies have been found between the propagation rates for different types and frequencies of eye movement. This study attempted to determine whether these differences could be explained by the affect of EOG magnitude on the correction procedure. Experiment 1 utilized simulated data to determine whether the combination of EOG magnitude and other forms of interference distorted the estimation of the propagation coefficients (Bs). Experiment 2 used real data to determine if the patterns obtained in Expt. 1 were apparent in real data. Matched t tests found that simulated low power EOG produced inflated Bs as a function of interference in Expt. 1. Experiment 2 found the same relationship between B and EOG magnitude as with the simulations. The findings are consistent with the thesis that eye movement related fields propagate similarly for a range of EOG types and frequencies, suggesting that the B differences reported in the literature are artifactual, and indicating the need for a new correction procedure.
Publisher: Wiley
Date: 10-05-2016
DOI: 10.1111/RISA.12634
Abstract: Precautionary messages have been shown to increase recipients' threat perceptions about radio-frequency electromagnetic fields (RF-EMFs) emitted by mobile phones and mobile phone base stations. The current study explored the interplay of variables on the side of message recipients with this effect. The in idual difference variables of interest were gender, trait anxiety, personal need for structure, and personal fear of invalidity. Furthermore, the study determined whether the increased threat perception is accompanied by emotional distress. A total of 298 university students answered a survey after reading either a basic text about RF-EMFs or a text including precautionary information. Linear multiple regression with interactions analyses showed that the effect of precautionary messages differed for people with different levels of trait anxiety. How trait anxiety was related to the effect of precautionary messages in turn depended on participants' gender. Personal need for structure and personal fear of invalidity were mostly unrelated to the effect of precautionary messages. Regarding participants' emotional distress, we found no difference in state anxiety scores between those participants who received precautionary information and those who did not. The findings show that the effects of precautionary messages on threat perception depend on in idual difference variables such as recipients' trait anxiety and gender. Also, the fact that precautionary communication did not result in heightened state anxiety challenges the assumption that precautionary messages induce fear or anxiety.
Publisher: Springer Science and Business Media LLC
Date: 05-2011
DOI: 10.1007/S10354-011-0881-Y
Abstract: A review of the scientific literature published until August 2010, covering epidemiological studies on the effects of RF EMF exposure on the incidence of brain tumours and leukaemia in children as well as experimental studies on RF EMF effects on cognition and CNS in children, reveals no or only scant evidence for the assumption that RF EMF exposure poses a hazard to children. This result is at odds with public risk perceptions, i.e. prevailing concerns of (at least part of) the public about adverse health effect of RF EMF. Consequences for risk communication are discussed. A scientifically sound and easy-to-understand risk communication is especially exacerbated by the fact that current risk assessments cannot exclude that RF EMF might have adverse health effects due remaining knowledge gaps, but especially due to the impossibility to prove a non-effect.
Publisher: SAGE Publications
Date: 2011
DOI: 10.1177/155005941104200110
Abstract: Lateralized differences in frontal alpha power in in iduals with major depressive disorder (MDD) are thought to reflect an aberrant affective processing style. However research into anterior alpha asymmetry and MDD has often produced conflicting results. The current study aimed to investigate whether in idualized alpha bandwidths provide a more sensitive measure of anterior alpha asymmetry in MDD than the traditional fixed 8–13 Hz alpha band. Resting EEG was recorded from 34 right-handed female participants (18 controls, 16 MDD). Each participant's In idual Alpha Frequency was used to delineate a broad in idualized alpha band and three in idualized narrow alpha sub-bands: lower alpha1, lower alpha 2 and upper alpha. Activity within the broad and narrow in idualized bandwidths and within the traditional fixed alpha band were used to compare a) controls and acutely depressed in iduals and b) medicated and unmedicated MDD participants. In idualizing and sub iding the alpha bandwidth did not add appreciably to the sensitivity of anterior alpha asymmetry in MDD as no significant differences in lateralized alpha power between controls and MDD participants were observed in any alpha bandwidth. This finding was consistent under two reference schemes and across multiple scalp locations. Within the MDD group, antidepressant use was associated with significantly greater right than left hemispheric power in the lower alpha 1 band. The relevance of this finding is discussed in relation to the electrophysiological correlates of antidepressant medication use, lateralized differences in affective processing and treatment resistant MDD.
Publisher: Wiley
Date: 25-01-2006
DOI: 10.1002/BEM.20209
Abstract: There is some evidence to suggest that exposure to mobile phones (MPs) can affect neural activity, particularly in response to auditory stimuli. The current investigation (n = 120) aimed to test recent findings in this area, namely that N100 litude and latency would decrease, and that P300 latency and reaction time (RT) would increase under active relative to sham exposure during an auditory task. Visual measures were also explored. A double blind, counterbalanced, crossover design was employed where subjects attended two sessions 1 week apart. In both sessions participants (1) performed auditory and visual oddball tasks while electroencephalogram (EEG) was recorded with a MP set to sham exposure mounted over the temporal region, and (2) performed the same tasks while the handset was set to active/sham. When active, the MP transmitted for 30 min at 895 MHz (average power 250 mW, pulse modulated at 217 Hz, average SAR 0.11 W/kg). Paired t-tests compared difference scores from the sham/sham session to those from the sham/active condition. The study was designed to detect differences of 1\\4 of a standard deviation with a power of 0.80. There was no significant difference between exposure conditions for any auditory or visual event related potential (ERP) component or RT. As previous positive findings were not replicated, it was concluded that there is currently no evidence that acute MP exposure affects these indices of brain activity.
Publisher: Elsevier BV
Date: 02-2000
Publisher: Springer Science and Business Media LLC
Date: 22-12-2004
DOI: 10.1007/S00213-004-2061-X
Abstract: The number of road fatalities related to the presence of hetamines in drivers has been relatively constant over the past 10 years. However, there remains uncertainty as to the extent that these drugs induce driving impairment, and whether any such impairments translate to an increase in road fatalities. To examine the acute effects of 0.42 mg/kg dex hetamine on simulated driving performance, and to establish which, if any, simulated driving abilities become impaired following dex hetamine administration. A repeated-measures, counter-balanced, double-blind, placebo-controlled design was employed. Twenty healthy volunteers completed two treatment conditions-0.42 mg/kg dex hetamine and placebo. Performance was assessed using a driving simulator task. Blood and saliva s les were obtained prior to the driving tasks and immediately after task completion (120 min and 170 min post-drug administration, respectively). Mean dex hetamine blood concentrations were 83 ng/ml and 98 ng/ml at 120 min and 170 min, respectively. Results indicated a decrease in overall simulated driving ability following dex hetamine administration during the day-time but not the night-time scenario tasks. Contributing to this performance reduction, "incorrect signalling", "failing to stop at a red traffic light" and "slow reaction times" were the behaviours most strongly affected by dex hetamine. The decrease in simulated driving ability observed during the day-time driving tasks are consistent with the perceptual narrowing or tunnel vision that is associated with dex hetamine consumption.
Publisher: Elsevier BV
Date: 11-2011
DOI: 10.1016/J.CLINPH.2011.04.006
Abstract: This study examined sensory and cognitive processing in adolescents, young adults and older adults, when exposed to 2nd (2G) and 3rd (3G) generation mobile phone signals. Tests employed were the auditory 3-stimulus oddball and the N-back. Forty-one 13-15 year olds, forty-two 19-40 year olds and twenty 55-70 year olds were tested using a double-blind cross-over design, where each participant received Sham, 2G and 3G exposures, separated by at least 4 days. 3-Stimulus oddball task: Behavioural: accuracy and reaction time of responses to targets were not affected by exposure. Electrophysiological: augmented N1 was found in the 2G condition (independent of age group). N-back task: Behavioural: the combined groups performed less accurately during the 3G exposure (compared to Sham), with post hoc tests finding this effect separately in the adolescents only. Electrophysiological: delayed ERD/ERS responses of the alpha power were found in both 3G and 2G conditions (compared to Sham independent of age group). Employing tasks tailored to each in idual's ability level, this study provides support for an effect of acute 2G and 3G exposure on human cognitive function. The subtlety of mobile phone effect on cognition in our study suggests that it is important to account for in idual differences in future mobile phone research.
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.ENVRES.2018.06.032
Abstract: While there has been consistent evidence that symptoms reported by in iduals who suffer from Idiopathic Environmental Intolerance attributed to Electromagnetic Fields (IEI-EMF) are not caused by EMF and are more closely associated with a nocebo effect, whether this response is specific to IEI-EMF sufferers and what triggers it, remains unclear. The present experiment tested whether perceived EMF exposure could elicit symptoms in healthy participants, and whether viewing an 'alarmist' video could exacerbate a nocebo response. Participants were randomly assigned to watch either an alarmist (N = 22) or control video (N = 22) before completing a series of sham and active radiofrequency (RF) EMF exposure provocation trials (2 open-label, followed by 12 randomized, double-blind, counterbalanced trials). Pre- and post-video state anxiety and risk perception, as well as belief of exposure and symptom ratings during the open-label and double-blind provocation trials, were assessed. Symptoms were higher in the open-label RF-ON than RF-OFF trial (p < .001). No difference in either symptoms (p = .183) or belief of exposure (p = .144) was observed in the double-blind trials. Participants who viewed the alarmist video had a significant increase in symptoms (p = .041), state anxiety (p < .01) and risk perception (p < .001) relative to the control group. These results reveal the crucial role of awareness and belief in the presentation of symptoms during perceived exposure to EMF, showing that healthy participants exhibit a nocebo response, and that alarmist media reports emphasizing adverse effects of EMF also contribute to a nocebo response.
Publisher: Public Library of Science (PLoS)
Date: 25-09-2015
Publisher: Elsevier BV
Date: 2013
DOI: 10.1016/J.AAP.2012.05.020
Abstract: Driving is a complex task, which can be broken down into specific cognitive processes. In order to determine which components contribute to drowsy driving impairments, the current study examined simulated driving and neurocognitive performance after one night of sleep deprivation. Nineteen professional drivers (age 45.3±9.1) underwent two experimental sessions in randomised order: one after normal sleep and one after 27h total sleep deprivation. A simulated driving task (AusEd), the psychomotor vigilance test (PVT), and neurocognitive tasks selected from the Cognitive Drug Research computerised neurocognitive assessment battery (simple and choice RT, Stroop Task, Digit Symbol Substitution Task, and Digit Vigilance Task) were administered at 10:00h in both sessions. Mixed-effects ANOVAs were performed to examine the effect of sleep deprivation versus normal sleep on performance measures. To determine if any neurocognitive tests predicted driving performance (lane position variability, speed variability, braking RT), neurocognitive measures that were significantly affected by sleep deprivation were then added as a covariate to the ANOVAs for driving performance. Simulated driving performance and neurocognitive measures of vigilance and reaction time were impaired after sleep deprivation (p<0.05), whereas tasks examining processing speed and executive functioning were not significantly affected by sleep loss. PVT performance significantly predicted specific aspects of simulated driving performance. Thus, psychomotor vigilance impairment may be a key cognitive component of driving impairment when sleep deprived. The generalisability of this finding to real-world driving remains to be investigated.
Publisher: IEEE
Date: 17-09-2023
Publisher: Elsevier BV
Date: 03-2000
DOI: 10.1016/S1388-2457(99)00256-4
Abstract: A form of EOG correction called the 'aligned-artifact average' (AAA) method has been advanced by the authors. In contrast to many previous methods, this used a correction coefficient (B), based on an average of eye movements rather than raw data, to remove eye movement related contamination from the EEG. The first part of this study was aimed at determining whether a variation of this procedure that is more easily implemented would produce a similar correction. The second part was designed to determine the number of epochs needed in an average to correct adequately. Subjects performed a series of eye movement tasks whilst EEG and EOG data were recorded. Data were manipulated according to either the AAA or an alternate new ERP method (NERP) and the resultant Bs were compared in part A. In part B, averages were created from varying numbers of epochs, and the resultant r(2)-values were compared. The AAA and NERP methods produced the same Bs, and averages with at least 40 epochs were required for adequate B estimation for both VEOG and HEOG. There is no difference between the AAA and NERP methods and thus it is acceptable to use the more easily implemented NERP method for EOG correction. It is recommended that when applying this procedure, at least 40 epochs should be used to make up the averages from which to calculate correction coefficients.
Publisher: Elsevier
Date: 2014
Publisher: Informa UK Limited
Date: 12-06-2014
Publisher: Springer Science and Business Media LLC
Date: 07-2003
DOI: 10.1007/BF02348091
Publisher: Springer Science and Business Media LLC
Date: 17-11-2000
Abstract: (+/-)-3,4-methylenedioxymeth het-amine (MDMA 'ecstasy'), a commonly used recreational drug, has typically been found to be related to poor cognitive function in humans. However, cannabis consumption may not have been adequately controlled for in these studies. The present study was designed to further elucidate the relation between MDMA and cannabis in cognitive impairment. Subjects who had used neither MDMA nor cannabis (controls n=31), cannabis but not MDMA (cannabis users n=18) and both MDMA and cannabis (MDMA/cannabis users n=11) were compared on a battery of neuropsychological tests. The cannabis and MDMA/cannabis groups did not differ on any of the tests, whereas the combined cannabis and MDMA/cannabis groups performed more poorly than controls on tests of memory, learning, word fluency, speed of processing and manual dexterity. Further, apart from speed of processing where higher MDMA consumption predicted slower processing, covariate analysis revealed that the deficits were more closely related to cannabis than MDMA usage. The results suggest that cannabis is an important confound in studies of MDMA-related cognitive impairment, and that previously reported cognitive impairment in MDMA users may have been caused by coincident cannabis use.
Publisher: Springer Science and Business Media LLC
Date: 29-06-2005
DOI: 10.1007/S00213-005-0042-3
Abstract: The Standardised Field Sobriety Tests (SFSTs), designed and validated to assess impairment associated with alcohol intoxication, are currently being employed by the Victoria Police (Australia) for the identification of driving impairment associated with drugs other than alcohol. The aim of this study was to evaluate whether the SFSTs are a sensitive measure for identifying the presence of dex hetamine and meth hetamine. Three studies each employed a repeated-measures, counterbalanced, double-blind placebo-controlled design. In each study, 20 healthy volunteers completed two treatment conditions: either 0.42 mg/kg d,l-dex hetamine and placebo, 0.42 mg/kg d,l-meth hetamine and placebo, or 0.42 mg/kg d-meth hetamine and placebo. Performance was assessed using the SFSTs, consisting of the Horizontal Gaze Nystagmus test, the Walk and Turn test, and the One Leg Stand test. Blood and saliva s les were obtained before and immediately after the administration of the SFSTs (120 and 170 min post drug administration). At 120 and 170 min post drug administration, d,l-dex hetamine blood levels were 83.16 and 98.42 ng/ml, respectively d,l-meth hetamine levels were 90 and 95 ng/ml, respectively and d-meth hetamine blood levels were 72 and 67 ng/ml, respectively. None of the three hetamine doses impaired performance on the SFSTs. Using the SFSTs, the presence of dex hetamine was identified in 5% of cases, d-meth hetamine in 5%, and d,l-meth hetamine in 0% of cases. Under these conditions, the SFSTs are not a sensitive measure for detecting the presence of low levels of hetamine.
Publisher: Springer Science and Business Media LLC
Date: 14-09-2015
Publisher: Elsevier BV
Date: 10-2009
DOI: 10.1016/J.JAD.2009.01.009
Abstract: Major Depressive Disorder is widely recognised to be a heterogeneous syndrome with numerous depressive phenotypes, one of which is melancholic depression. Patients with melancholic depression exhibit treatment responses and outcomes that differ from patients with non-melancholic depression. The current study aimed to assess whether differences existed between melancholic and non-melancholic subtypes of depression, as measured by the event related potential, intensity dependence of the auditory evoked potential (IDAEP). IDAEP was assessed in 14 melancholic and 13 non-melancholic depressed subjects and 14 controls. The melancholic patients had a significantly shallower IDAEP slope than the non-melancholic patients not explained by depression severity or age. Antidepressants were taken by all patients in this study and the effect of continual use of these drugs on the IDAEP slopes has yet to be confirmed. These results provide support for neurobiological differences between melancholic and non-melancholic depressive subtypes. Melancholic depression may be characterized by ongoing over function of the serotonin system in spite of medication treatment.
Publisher: Elsevier BV
Date: 10-2014
Publisher: Proceedings of the National Academy of Sciences
Date: 13-06-2000
Abstract: Investigations using hippoc al slices maintained in vitro have demonstrated that bursts of oscillatory field potentials in the gamma frequency range (30–80 Hz) are followed by a slower oscillation in the beta 1 range (12–20 Hz). In this study, we demonstrate that a comparable gamma-to-beta transition is seen in the human electroencephalogram (EEG) in response to novel auditory stimuli. Correlations between gamma and beta 1 activity revealed a high degree of interdependence of synchronized oscillations in these bands in the human EEG. Evoked (stimulus-locked) gamma oscillations preceded beta 1 oscillations in response to novel stimuli, suggesting that this may be analogous to the gamma-to-beta shift observed in vitro . Beta 1 oscillations were the earliest discriminatory responses to show enhancement to novel stimuli, preceding changes in the broad-band event-related potential (mismatch negativity). Later peaks of induced beta activity over the parietal cortex were always accompanied by an underlying gamma frequency oscillation as seen in vitro. A further analogy between in vitro and human recordings was that both gamma and beta oscillations habituated markedly after the initial novel stimulus presentation.
Publisher: Public Library of Science (PLoS)
Date: 07-06-2022
DOI: 10.1371/JOURNAL.PONE.0269457
Abstract: Little was known about the relationship between carrying mobile phone handsets by men and their risk perception of radiofrequency-electromagnetic field (RF-EMF) exposure due to carrying handsets close to the body. This study aimed to determine where men usually carried their handsets and to assess the relationship to risk perception of RF-EMF. Participants completed a self-administered questionnaire about mobile phone use, handset carrying locations, and levels of risk perception to RF-EMF. Data were analysed using linear regression models to examine if risk perception differed by mobile phone carrying location. The participants were 356 men, aged 18–72 years. They owned a mobile phone for 2–29 years, with over three quarters (78.7%) having a mobile phone for over 20 years. The most common locations that men kept their handsets when they were ‘indoors’ were: on a table/desk (54.0%) or in close contact with the body (34.7%). When outside, 54.0% of men kept the handset in the front trouser pocket. While making or receiving calls, 85.0% of men held their mobile phone handset against the head and 15.0% either used earphones or loudspeaker. Men who carried their handset in close contact with the body perceived higher risks from RF-EMF exposure compared to those who kept it away from the body (p .01). A substantial proportion of men carried their mobile phone handsets in close proximity to reproductive organs i.e. front pocket of trousers (46.5%). Men who kept their handset with the hand (p .05), and those who placed it in the T-shirt pocket (p .05), while the phone was not in use, were more likely to perceive health risks from their behaviour, compared to those who kept it away from the body. However, whether this indicates a causal relationship, remains open.
Publisher: Elsevier BV
Date: 09-2003
DOI: 10.1016/S1388-2457(03)00112-3
Abstract: This study investigated the effects of stimulant medications on the Electroencephalography (EEG) of children with the combined type of attention-deficit/hyperactivity disorder (ADHD) together with excessive beta activity in their EEG. Twenty ADHD and 20 control subjects participated in this study. EEG was recorded from 21 sites during an eyes-closed resting condition and Fourier transformed to provide estimates for total power and absolute and relative power in the delta, theta, alpha and beta bands, and for the theta/alpha and theta/beta ratios. Subjects were placed on a 6-month trial of a stimulant medication and a second EEG was recorded at the end of the trial. The unmedicated ADHD group had greater absolute and relative beta, less absolute and relative alpha, a higher theta/alpha and a lower theta/beta ratio than the control group. In the frontal regions the ADHD group had an increase in total power, absolute theta, absolute and relative beta and the theta/beta ratio, with greater relative delta, relative theta, and absolute and relative alpha in posterior regions. With medication use, absolute beta activity and frontal total power decreased, although these changes represented a reduction in power, not a normalisation. These results indicate that ADHD children with excessive beta activity in their EEG are probably not hypoaroused as previously suggested, and that beta activity in these children is probably only associated with the impulsivity and/or hyperactivity aspects of the disorder, but may not necessarily be associated with inattention. This study is the first to investigate effects of stimulant medications on the EEG of ADHD children with excessive beta activity in their EEG.
Publisher: Springer Science and Business Media LLC
Date: 12-2008
DOI: 10.1007/BF03178595
Publisher: SAGE Publications
Date: 07-2008
DOI: 10.1177/155005940803900308
Abstract: The objective of this study was to explore the effects of 1Hz repetitive transcranial magnetic stimulation (rTMS) applied to dorsal lateral prefrontal cortex (DLPFC) on both an EEG index of cortical excitation and inhibition, event-related desynchronization/synchronization (ERD/S) and on the P300 component of an auditory oddball-induced ERP. Eight normal participants received 15 minutes of 1Hz rTMS at 110% of the resting motor threshold to right DLPFC. ERD/S of alpha and beta bands was measured during an auditory oddball task immediately before and after stimulation. There was significantly less alpha desynchronization post-TMS, and this effect was widespread excepting posterior midline sites. No changes were found to oddball-P300 litudes or latencies. In conclusion, the findings of less alpha desynchronization post-TMS are compatible with notions of slow rTMS causing a decrease in cortical excitation.
Publisher: Elsevier BV
Date: 06-2015
DOI: 10.1016/J.IJPSYCHO.2015.04.011
Abstract: P50 suppression refers to the litude-reduction of the P50 event related potential to the second (S2) relative to the first (S1) of identical auditory stimuli presented 500ms apart. Theory suggests that refractory periods (RPs) and/or inhibitory inputs (II) underlie P50 suppression. The present study manipulated interval between stimulus pairs (IPI: 2, 8s) and direction of participants' attention (Attention, Non-Attention) in order to determine which theory best explains P50 suppression. The rationale is that: 1/ RP and II predict opposite effects of manipulating the functionality of the mechanism responsible for S2P50 suppression (e.g. reducing function would increase S2P50 according to the II and decrease S2P50 according to the RP hypothesis) 2/ IPI2 (relative to IPI8) will reduce functionality of the mechanism responsible for S2P50 suppression, as it results in less recovery of (and a greater challenge to) that mechanism - RP would thus predict reduced S2P50, whereas II would predict enhanced S2P50 litude and 3/ where the mechanism responsible for S2P50 suppression is challenged (i.e. at IPI2, due to insufficient recovery), Attention (relative to Non-Attention) will enhance functionality of this mechanism - RP would thus predict increased S2P50, whereas II would predict reduced S2P50 litude. In the Non-Attention paradigm, reducing IPI from 8 to 2s tended to increase S2P50 litude (and consequently impaired P50 suppression), and in the 2s IPI paradigm, directing attention towards the stimuli reduced S2P50 litude (and improved P50 suppression), with both effects supporting the II hypothesis only.
Publisher: SAGE Publications
Date: 07-2010
DOI: 10.1177/155005941004100304
Abstract: The stop signal task is used to investigate inhibition of an initiated response. Converging evidence suggests that right inferior prefrontal cortex is involved in this behavior, although other regions in the prefrontal cortex have also been implicated. One technique used to determine the contribution of specific cortical regions to behavior is repetitive transcranial magnetic stimulation (rTMS). In the present study, fourteen subjects performed the stop signal task before and after receiving a train of rTMS to the left and right dorsolateral prefrontal cortex (DLPFC). The effects of rTMS were determined using event-related potential (ERP) measures that have been associated with response inhibition in previous studies. Stimulation of left and right DLPFC did not affect ERP measures of response inhibition. This negative finding is interpreted with caution, but is consistent with a recent study which found that stimulation of the same region had no effect on a behavioral measure of response inhibition.
Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.JMBBM.2014.12.017
Abstract: Localised delivery of appropriate biomolecule/drug(s) can be suitable to prevent postoperative infections and inflammation after scaffold implantation in vivo. In this study composite shell scaffolds, based on an internally produced bioactive glass and a commercial hydroxyapatite, were surface coated with a uniform polymeric layer, embedded with thermo-stable polyesterurethane (PU)-based nanoparticles (NPs), containing an anti-inflammatory drug (indomethacin IDCM). The obtained functionalised scaffolds were subjected to physico-mechanical and biological characterisations. The results indicated that NPs incorporation into the gelatin coating of the composite scaffolds: 1) not changed significantly the micro-architecture of the scaffolds in terms of mean pore diameter and pore size distribution 2) increased the compressive modulus and 3) allowed to a sustained IDMC release (65-70% of the loaded-drug) within the first week of incubation in physiological solution. On the other hand, the NPs incorporation did not affect the biocompatibility of composite scaffolds, as evidenced by viability and alkaline phosphatase (ALP) activity of MG63 human osteoblast-like cells.
Publisher: Elsevier BV
Date: 09-2010
Publisher: Wiley
Date: 26-06-2012
DOI: 10.1002/JBM.A.34271
Abstract: Bioceramic "shell" scaffolds, with a morphology resembling the cancellous bone microstructure, have been recently obtained by means of a new protocol, developed with the aim to overcome the limits of the conventional foam replication technique. Because of their original microstructure, the new s les combine high porosity, permeability, and manageability. In this study, for the first time, the novel bioactive glass shell scaffolds are provided with a gelatin-based biomimetic coating to realize hybrid implants which mimic the complex morphology and structure of bone tissue. Moreover, the presence of the coating completely preserves the in vitro bioactivity of the bioactive glass s les, whose surfaces are converted into hydroxyapatite after a few days of immersion in a simulated body fluid solution (SBF).
Publisher: Elsevier BV
Date: 09-1998
Publisher: Mary Ann Liebert Inc
Date: 30-08-2023
Publisher: Elsevier BV
Date: 08-2016
DOI: 10.1016/J.PSCYCHRESNS.2016.07.002
Abstract: Episodic memory (EM) impairments in schizophrenia (SZ) are predictive of functional outcome and are a potential endophenotype of the disorder. The current study investigated the neuroanatomical correlates of EM encoding and retrieval in SZ with structural magnetic resonance and diffusion tensor imaging (DTI) measures in 22 patients with SZ and 22 age- and gender-matched healthy controls. Tract-based Spatial Statistics (TBSS) was used to investigate microstructural alterations in white matter (WM), while FreeSurfer surface-based analysis was used to determine abnormalities in grey matter (GM) and WM volumetrics and cortical thickness. Compared to controls, patients demonstrated GM deficits in temporal and parietal regions and lower fractional anisotropy (FA) of WM in diffuse brain regions. Patients also demonstrated reduced functioning in both encoding and retention of auditory-verbal EM. Among patients but not controls, EM encoding correlated with WM volume in the orbitofrontal cortex and increased radial diffusivity in the fornix, whereas EM retrieval correlated with WM volume in posterior parietal cortex. These findings suggest a differential role for frontal and parietal WM in EM encoding and retrieval processes, while myelin integrity of the fornix may play a specific role in mediating EM encoding processes in SZ.
Publisher: Informa UK Limited
Date: 12-2018
DOI: 10.2147/IJN.S183767
Publisher: Springer Science and Business Media LLC
Date: 05-2004
DOI: 10.1007/S00213-004-1791-0
Abstract: It has been suggested that 3,4-methylenedioxymeth hetamine (MDMA or ecstasy) causes damage to the serotonergic system, and that this damage results in cognitive and mood impairments. To examine the effect of chronic MDMA usage on a wide battery of cognitive tests and psychological abilities and processes. In the present study, the performance of 17 participants with a history of MDMA use was compared to the performance of 15 control subjects on a battery of neuropsychological tests. This battery included tests for depression, immediate word recall, delayed recall, attention and working memory. Results indicated that the MDMA group had significantly higher scores for depression than the control group, and displayed poorer delayed recall and verbal learning than controls after accounting statistically for the effects of cannabis and depression. These results suggest that MDMA users exhibit difficulties in coding information into long-term memory, display impaired verbal learning, are more easily distracted, and are less efficient at focusing attention on complex tasks.
Publisher: Wiley
Date: 02-08-2010
DOI: 10.1002/BEM.20583
Abstract: The present study was conducted to determine whether adolescents and/or the elderly are more sensitive to mobile phone (MP)-related bioeffects than young adults, and to determine this for both 2nd generation (2G) GSM, and 3rd generation (3G) W-CDMA exposures. To test this, resting alpha activity (8-12 Hz band of the electroencephalogram) was assessed because numerous studies have now reported it to be enhanced by MP exposure. Forty-one 13-15 year olds, forty-two 19-40 year olds, and twenty 55-70 year olds were tested using a double-blind crossover design, where each participant received Sham, 2G and 3G exposures, separated by at least 4 days. Alpha activity, during exposure relative to baseline, was recorded and compared between conditions. Consistent with previous research, the young adults' alpha was greater in the 2G compared to Sham condition, however, no effect was seen in the adolescent or the elderly groups, and no effect of 3G exposures was found in any group. The results provide further support for an effect of 2G exposures on resting alpha activity in young adults, but fail to support a similar enhancement in adolescents or the elderly, or in any age group as a function of 3G exposure.
Publisher: Elsevier BV
Date: 09-2006
DOI: 10.1016/J.PBB.2006.07.013
Abstract: Animal studies have demonstrated that the co-administration of pindolol and selective serotonin reuptake inhibitors (SSRIs) potentiate serotonergic functioning to a greater degree than SSRIs alone. However, clinical trials of pindolol augmentation in patients with major depressive disorder have reported contradictory findings, and the central effects of this treatment regime on serotonin functioning in humans are unknown. The current double-blind placebo controlled repeated measures investigation used the loudness dependence auditory evoked potential (LDAEP) to assess central serotonin functioning in healthy participants across three acute treatment conditions: placebo, citalopram (20 mg), and pindolol (10 mg)+citalopram (20 mg). The current paper focuses on the effects of pindolol augmentation of citalopram as compared to the administration of citalopram alone. Enhancement of serotonin function with citalopram in comparison to placebo decreased the slope of the LDAEP (i.e. weaker LDAEP). However, there were no significant differences between the changes in the LDAEP induced by co-administration of pindolol and citalopram compared to citalopram. The present results indicate that, in healthy controls, pindolol augmentation of SSRIs does not potentiate central serotonin function to a greater degree than the administration of an SSRI alone. The findings may provide further support for why pindolol may not be an effective therapeutic strategy to augment serotonin function and antidepressant response.
Publisher: Springer Science and Business Media LLC
Date: 20-07-2012
DOI: 10.1007/S00213-011-2395-0
Abstract: Caffeine exerts positive effects on cognitive and behavioral processes, especially in sub-optimal conditions when arousal is low. Apart from caffeine, coffee contains other compounds including the phenolic compounds ferulic acid, caffeic acid, and the chlorogenic acids, which have purported antioxidant properties. The chlorogenic acids are the most abundant family of compounds found in coffee, yet their effects on cognition and mood have not been investigated. This study aims to ascertain whether a coffee rich in chlorogenic acid modulates brain function. The present pilot study examined the acute effects of decaffeinated coffee with regular chlorogenic acid content and decaffeinated coffee with high chlorogenic acid content on mood and cognitive processes, as measured by behavioral tasks and event-related potentials (ERPs). Performance and ERP responses to a battery of cognitive tasks were recorded at baseline and following the equivalent of three cups of coffee in a randomized, double-blind, crossover study of 39 healthy older participants. Compared with the decaffeinated coffee with regular chlorogenic acid and placebo, caffeinated coffee showed a robust positive effect on higher-level mood and attention processes. To a lesser extent, the decaffeinated coffee high in chlorogenic acid also improved some mood and behavioral measures, relative to regular decaffeinated coffee. Our pilot results suggest that non-caffeine compounds in coffee such as the chlorogenic acids may be capable of exerting some acute behavioral effects, thus warranting further investigation.
Publisher: Wiley
Date: 2010
DOI: 10.1002/BEM.20578
Abstract: This is the first of two articles addressing the most appropriate crossover frequency at which incident power flux density (S(inc)) replaces the spatial peak value of the specific energy absorption rate (SAR) averaged over 1 or 10 g (i.e., peak 1 or 10 g SAR) as the basic restriction for protecting against radiofrequency (RF) heating effects in the 1-10 GHz range. Our general approach has been to compare the degree of correlation between these basic restrictions and the peak induced tissue temperature rise (DeltaT) for a representative range of population/exposure scenarios. In this article we particularly address the effect of human population ersity in the thickness of body tissue layers at eight different sites of the body. We used a Monte Carlo approach to specify 32000 models (400 models for each of 8 body sites for 10 frequencies) which were representative of tissue thicknesses for age (18-74 years) and sex at the eight body sites. Histogram distributions of S(inc) and peak 1 and 10 g SAR corresponding to a peak 1 degrees C temperature rise were obtained from RF and thermal analyses of 1D multiplanar models exposed to a normally incident plane wave ranging from 1 to 10 GHz in thermo-neutral environmental conditions. Examination of the distribution spread of the histograms indicated that peak SAR was a better predictor of peak tissue temperature rise across the entire 1-10 GHz frequency range than S(inc), as indicated by the smaller spread in its histogram distributions, and that peak 10 g SAR was a slightly better predictor than peak 1 g SAR. However, this result must be weighed against partly conflicting indications from complex body modeling in the second article of this series, which incorporates near-field effects and the influence of complex body geometries.
Publisher: Springer Science and Business Media LLC
Date: 26-09-2007
Abstract: Schizophrenia is associated with impairments of sensorimotor and sensory gating as measured by prepulse inhibition (PPI) of the acoustic startle response and P50 suppression of the auditory event-related potential respectively. While serotonin and dopamine play an important role in the pathophysiology and treatment of schizophrenia, their role in modulating PPI and P50 suppression in humans is yet to be fully clarified. To further explore the role of serotonin and dopamine in PPI and P50 suppression, we examined the effects of acute tryptophan depletion (to decrease serotonin) and acute tyrosine henylalanine depletion (to decrease dopamine) on PPI and P50 suppression in healthy human participants. In addition, we also examined for the first time, the effects of simultaneous serotonin and dopamine depletion (ie combined monoamine depletion) on PPI and P50 suppression. The study was a double-blind, placebo-controlled cross-over design in which 16 healthy male participants completed the PPI and P50 paradigms under four acute treatment conditions: (a) balanced lacebo control, (b) acute tryptophan depletion, (c) acute tyrosine henylalanine depletion, and (d) acute tyrosine henylalanine/tryptophan depletion (combined monoamine depletion). Selective depletion of dopamine had no significant effect on either PPI or P50 suppression, whereas selective serotonin depletion significantly disrupted PPI, but not P50 suppression. Finally, the simultaneous depletion of both serotonin and dopamine resulted in significant reduction of both PPI and P50 suppression. We suggest these results can be explained by theories relating to optimal levels of monoaminergic neurotransmission and synergistic interactions between serotonergic and dopaminergic systems for normal 'gating' function. These findings suggest that a dysfunction in both serotonin and dopamine neurotransmission may, in part, be responsible for the gating deficits observed in schizophrenia, and their normalization following administration of atypical antipsychotic drugs.
Publisher: Elsevier BV
Date: 04-2012
Publisher: Wiley
Date: 27-09-2011
DOI: 10.1111/J.1469-8986.2011.01262.X
Abstract: The utility of P50 paired-click measures is limited by their unestablished reliability, unknown effects of time, and long protocol. This study measured within-session reliability, temporal course, effect of varying interpair interval (IPI), and peak definition and ratio calculation methods on P50 paired-click measures in healthy participants. Results indicate higher reliability for difference (ICC=.72) than ratio (ICC=.44) method when P50 peaks are defined as baseline-to-peak than peak-to-peak time-related changes and comparable P50 paired-click measures at long (9 s) and short (3-7 s) IPIs. After controlling for time effects, P50 paired-click measures are relatively reliable within-session and are best measured using the difference method and defined as baseline-to-peak litude time effects must be taken into account when measuring P50 paired-click measures in a long paradigm and IPI can be shortened in studies with healthy s les.
Publisher: SAGE Publications
Date: 02-10-2010
Abstract: Antidepressants targeting the serotonergic system have been shown to modulate biases in emotional processing. The effects of serotonergic modulation on the temporal course of emotional processing (accruing within milliseconds) are unknown. Furthermore, it is unknown how serotonin affects different stages of facial emotional processing. The current study investigated the effects of acute serotonin augmentation on event-related potential (ERP) measures associated with ‘structural encoding’ (N170) and emotion ‘expression decoding’ (N250 and a late slow-wave positive potential [LPP]) of happy and sad facial stimuli, relative to neutral facial stimuli. The study was a double-blind, placebo-controlled, cross-over design, in which 14 healthy male participants completed a facial recognition task under two acute treatment conditions: 1) placebo (PLB) and 2) 20 mg citalopram (CIT). ERP recording were conducted while subjects viewed neutral, happy and sad facial stimuli. Findings indicated that under PLB, the N170 was not modulated by valence (happy or sad versus neutral), but the N250 and LPP were enhanced for processing happy (relative to neutral) faces. Citalopram had no effect on the N170, but it enhanced the LPP for processing sad (relative to neutral) faces. These findings suggest that serotonin enhancement has selective and temporal effects on emotional face processing, with evidence for modulating processes associated with ‘expression decoding’ but not ‘structural encoding’. The enhanced cortical response to perception of moderately intense sad facial expressions following citalopram administration may relate to the cognitive processing of the social relevance or significance of such ambiguous stimuli.
Publisher: Elsevier BV
Date: 05-2021
Publisher: Wiley
Date: 07-2008
DOI: 10.1002/HUP.940
Abstract: The loudness dependence of the auditory evoked potential (LDAEP) has been proposed as a valid means of non-invasively assessing in vivo central serotonin (5-hydroxytryptamine, 5-HT) function in humans. The specificity and sensitivity of the LDAEP to changes in 5-HT neurotransmission have recently been explored directly in a number of pharmacological and genetic studies. Subsequently, this review was undertaken in an attempt to critically evaluate the potential role of the LDAEP as a marker of the central 5-HT function. Findings from clinical, experimental animal and human studies examining the relationship between the LDAEP and the 5-HT system as well as other neurochemical systems including dopaminergic, glutamatergic and the cholinergic systems were reviewed. The majority of evidence for an association between the LDAEP and 5-HT has come from animal studies. Indirect studies in clinical disorders of presumed serotonergic dysfunction have been circumstantial and inconsistent with more recent investigations utilising direct genetic association studies also providing conflicting reports. Pharmacological studies in humans provide overwhelming evidence that the LDAEP is insensitive to acute changes in 5-HT function, with additional evidence outlining sensitivity to other neurotransmitter systems including the glutamatergic system. The available evidence suggests that the LDAEP lacks sensitivity and specificity to acute changes in serotonergic neurotransmission. Overall the findings do not provide strong support for its utility as a marker of central 5-HT function. However the LDAEP shows more promise as a potential predictor of antidepressant treatment response and this predictive ability may provide the basis for future research involving the LDAEP.
Publisher: Springer Science and Business Media LLC
Date: 16-06-2015
DOI: 10.1038/SREP10980
Abstract: The effect of electromagnetic field (EMF) exposures at the microwave (MW) frequency of 18 GHz, on four cocci, Planococcus maritimus KMM 3738, Staphylococcus aureus CIP 65.8 T , S. aureus ATCC 25923 and S. epidermidis ATCC 14990 T , was investigated. We demonstrate that exposing the bacteria to an EMF induced permeability in the bacterial membranes of all strains studied, as confirmed directly by transmission electron microscopy (TEM) and indirectly via the propidium iodide assay and the uptake of silica nanospheres. The cells remained permeable for at least nine minutes after EMF exposure. It was shown that all strains internalized 23.5 nm nanospheres, whereas the internalization of the 46.3 nm nanospheres differed amongst the bacterial strains ( S. epidermidis ATCC 14990 T ~ 0% Staphylococcus aureus CIP 65.8 T S. aureus ATCC 25923, ~40% Planococcus maritimus KMM 3738, ~80%). Cell viability experiments indicated that up to 84% of the cells exposed to the EMF remained viable. The morphology of the bacterial cells was not altered, as inferred from the scanning electron micrographs, however traces of leaked cytosolic fluids from the EMF exposed cells could be detected. EMF-induced permeabilization may represent an innovative, alternative cell permeability technique for applications in biomedical engineering, cell drug delivery and gene therapy.
Publisher: SAGE Publications
Date: 08-07-2011
Abstract: An impaired capacity to filter or ‘gate’ sensory information is a core deficit in cognitive function associated with schizophrenia. These deficits have been linked in part to N-methyl-d-aspartate (NMDA) receptor dysfunction. An association between high levels of glycine, a positive allosteric modulator of the NMDA receptor, and sensorimotor gating impairments (i.e. prepulse inhibition (PPI) deficit) have been reported in animal models of schizophrenia as well as patients with schizophrenia. This study examined the acute effects of modulating the glycine site of the NMDA receptor (with high-dose glycine) on sensory gating as measured by PPI. Sixteen healthy male subjects (final s le size of 12) participated in a double-blind, placebo-controlled, crossover design in which each subject was tested under two acute treatment conditions separated by at least a 5-day washout period placebo and 0.8 g/kg glycine. PPI was recorded 45 min post treatment using electromyography of the eye-blink response. Relative to placebo, high-dose glycine significantly impaired sensorimotor gating as demonstrated by a decrease in PPI ( t(11) = −2.983, p 0.05). Administration of a high dose of glycine is associated with impairments in PPI supporting earlier observations in animals and patients with schizophrenia. This result, when taken together with findings in patients, suggests that high synaptic levels of glycine may have some clinically relevant detrimental effects and suggests a potential dissociation of clinical symptomatology and sensory information processing as a function of NMDA receptor modulation in schizophrenia.
Publisher: Elsevier BV
Date: 08-2006
DOI: 10.1016/J.CLINPH.2006.04.015
Abstract: This study investigated EEG differences between children with attention-deficit/hyperactivity disorder (AD/HD) and matched control subjects, with either normal or low IQs. Twenty normal-IQ and 20 low-IQ children with AD/HD, and 40 age-, IQ- and sex-matched control subjects participated in this study. EEG was recorded from 21 sites during an eyes-closed resting condition and Fourier transformed to provide estimates for total power, and absolute and relative power in the delta, theta, alpha and beta bands. Children with AD/HD had increased theta activity with decreased levels of alpha and beta activity compared to control subjects. IQ was not found to impact on the EEG. No significant differences were found between subjects with normal and low IQs, with the low- and high-IQ AD/HD groups having similar EEG profiles. Low-IQ children with AD/HD have similar EEG abnormalities to those with normal IQs, and IQ does not appear to impact on EEG power measures. This is the first study to investigate EEG differences in low-IQ children with and without AD/HD.
Publisher: Springer Science and Business Media LLC
Date: 28-09-2010
DOI: 10.1007/S00221-010-2369-1
Abstract: Several studies have found that response inhibition in the stop signal task is associated with a delay in subsequent response speed, which may result from the automatic retrieval of a conflicting stimulus-goal association. This study investigated the neurophysiological correlates of this sequence effect using event related potentials (ERPs). ERPs were recorded in 17 healthy people while they performed the stop signal task. We found reduced P3b litude for responses following successful inhibition, but only when the stimulus was repeated from the previous trial (repetition-after-effects). For responses following failed inhibition, P3b litude was reduced regardless of stimulus repetition status. We also found a general increase in frontal N2 litude on response trials following inhibition, regardless of stimulus repetition or behavioural slowing. The complex pattern of ERP findings, dependent on stimulus repetition and success of inhibition, suggests multiple sources of behavioural slowing in the present data. ERP findings suggest that a memory retrieval processes underlies the repetition component of inhibition after effects. These findings are considered within the broader context of ERP findings in the negative priming literature.
Publisher: Oxford University Press (OUP)
Date: 09-01-2014
Publisher: Elsevier BV
Date: 02-2003
DOI: 10.1016/S1388-2457(02)00364-4
Abstract: This study investigated the EEG of girls with Attention-deficit/hyperactivity disorder (ADHD). Subjects consisted of 100 girls with ADHD between the ages of 8 and 12 years and 40 age- and gender-matched controls. EEG was recorded from 21 sites during an eyes-closed resting condition and Fourier transformed to provide estimates for total power, and relative power in the delta, theta, alpha and beta bands. Factor analysis was used to group sites into 3 regions, covering frontal, central and posterior regions. The total ADHD group was compared to the control group as well as the data being subjected to cluster analysis. The ADHD subjects had greater total power, more relative theta, and less relative delta, alpha and beta than controls. Cluster analysis indicated the presence of two distinct EEG clusters of girls with ADHD. These were (a) a large subgroup characterized by increased total power, more relative theta, and less relative delta and beta than control subjects and (b) a small subgroup with a substantially-increased amount of high litude theta activity, with deficiencies in all other bands. These results indicate that girls with ADHD exhibit abnormalities in their EEGs, but there is far less variance in their EEG profiles than is found in boys with the disorder. The results also suggest that there may be distinct groups of girls with ADHD who are not being referred for clinical treatment. Recommendations are made for further research in this population. This study is significant in that it is the first major study to separately investigate the EEG of girls with ADHD.
Publisher: Wiley
Date: 03-08-2011
DOI: 10.1002/BEM.20691
Abstract: Mobile phone exposure-related effects on the human electroencephalogram (EEG) have been shown during both waking and sleep states, albeit with slight differences in the frequency affected. This discrepancy, combined with studies that failed to find effects, has led many to conclude that no consistent effects exist. We hypothesised that these differences might partly be due to in idual variability in response, and that mobile phone emissions may in fact have large but differential effects on human brain activity. Twenty volunteers from our previous study underwent an adaptation night followed by two experimental nights in which they were randomly exposed to two conditions (Active and Sham), followed by a full-night sleep episode. The EEG spectral power was increased in the sleep spindle frequency range in the first 30 min of non-rapid eye movement (non-REM) sleep following Active exposure. This increase was more prominent in the participants that showed an increase in the original study. These results confirm previous findings of mobile phone-like emissions affecting the EEG during non-REM sleep. Importantly, this low-level effect was also shown to be sensitive to in idual variability. Furthermore, this indicates that previous negative results are not strong evidence for a lack of an effect and, given the far-reaching implications of mobile phone research, we may need to rethink the interpretation of results and the manner in which research is conducted in this field.
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.CLINPH.2013.12.111
Abstract: This study aimed to characterise, emotion perception deficits in symptomatic Huntington's disease (HD) via the use of event-related potentials (ERPs). ERP data were recorded during a computerised facial expression task in 11 HD participants and 11 matched controls. Expression (scrambled, neutral, happy, angry, disgust) classification accuracy and intensity were assessed. Relationships between ERP indices and clinical disease characteristics were also examined. Accuracy was significantly lower for HD relative to controls, due to reduced performance for neutral, angry and disgust (but not happy) faces. Intensity ratings did not differ between groups. HD participants displayed significantly reduced visual processing litudes extending across pre-face (P100) and face-specific (N170) processing periods, whereas subsequent emotion processing litudes (N250) were similar across groups. Face-specific and emotion-specific derivations of the N170 and N250 ('neutral minus scrambled' and 'each emotion minus neutral', respectively) did not differ between groups. Our data suggest that the facial emotion recognition performance deficits in HD are primarily related to neural degeneration underlying 'generalised' visual processing, rather than face or emotional specific processing. ERPs are a useful tool to separate functionally discreet impairments in HD, and provide an important avenue for biomarker application that could more-selectively track disease progression.
Publisher: Frontiers Media SA
Date: 30-06-2016
Publisher: Informa UK Limited
Date: 08-08-2016
DOI: 10.1080/09553002.2016.1213454
Abstract: To investigate whether exposure to pulse modulated radiofrequency (PM RF) influences human cognitive performance, and whether it does so in a dose-dependent manner. Thirty-six healthy adults participated in a randomized, double-blind, counterbalanced provocation study. Cognitive performance was assessed using a visual discrimination task and a modified Sternberg working memory task, which were calibrated to in idual performance levels in a preliminary testing session. An sXh920 planar exposure system was used to generate a 920 MHz GSM-like signal, providing three conditions (peak-spatial SAR averaged over 10 g) of 0 W/kg (sham), 1 W/kg (low RF) and 2 W/kg (high RF). A significant decrease in reaction time (RT) in the Sternberg working memory task was found during exposure compared to sham. This effect was not dose-dependent. Cognitive performance was shown to be faster under PM RF conditions, relative to sham, in a working memory task. While the majority of the literature has not found effects of PM RF exposure on cognitive performance, it is possible that the methodological improvements employed in the present study increased sensitivity, and thus the ability to detect potential effects.
Publisher: Informa UK Limited
Date: 02-12-2015
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2014
Publisher: SAGE Publications
Date: 09-2010
Publisher: Elsevier BV
Date: 09-2004
Publisher: MDPI AG
Date: 31-01-2019
Abstract: High frequency (HF) electromagnetic fields (EMFs) have been widely used in many wireless communication devices, yet within the terahertz (THz) range, their effects on biological systems are poorly understood. In this study, electromagnetic radiation in the range of 0.3–19.5 × 1012 Hz, generated using a synchrotron light source, was used to investigate the response of PC 12 neuron-like pheochromocytoma cells to THz irradiation. The PC 12 cells remained viable and physiologically healthy, as confirmed by a panel of biological assays however, exposure to THz radiation for 10 min at 25.2 ± 0.4 °C was sufficient to induce a temporary increase in their cell membrane permeability. High-resolution transmission electron microscopy (TEM) confirmed cell membrane permeabilization via visualisation of the translocation of silica nanospheres (d = 23.5 ± 0.2 nm) and their clusters (d = 63 nm) into the PC 12 cells. Analysis of scanning electron microscopy (SEM) micrographs revealed the formation of atypically large (up to 1 µm) blebs on the surface of PC 12 cells when exposed to THz radiation. Long-term analysis showed no substantial differences in metabolic activity between the PC 12 cells exposed to THz radiation and untreated cells however, a higher population of the THz-treated PC 12 cells responded to the nerve growth factor (NGF) by extending longer neurites (up to 0–20 µm) compared to the untreated PC12 cells (up to 20 µm). These findings present implications for the development of nanoparticle-mediated drug delivery and gene therapy strategies since THz irradiation can promote nanoparticle uptake by cells without causing apoptosis, necrosis or physiological damage, as well as provide a deeper fundamental insight into the biological effects of environmental exposure of cells to electromagnetic radiation of super high frequencies.
Publisher: MDPI AG
Date: 29-09-2016
Publisher: Elsevier BV
Date: 06-2001
Publisher: International Union of Crystallography (IUCr)
Date: 20-06-2023
DOI: 10.1107/S1600577523004228
Abstract: The routes by which foreign objects enter cells is well studied however, their fate following uptake has not been explored extensively. Following exposure to synchrotron-sourced (SS) terahertz (THz) radiation, reversible membrane permeability has been demonstrated in eukaryotic cells by the uptake of nanospheres nonetheless, cellular localization of the nanospheres remained unclear. This study utilized silica core-shell gold nanospheres (AuSi NS) of diameter 50 ± 5 nm to investigate the fate of nanospheres inside pheochromocytoma (PC 12) cells following SS THz exposure. Fluorescence microscopy was used to confirm nanosphere internalization following 10 min of SS THz exposure in the range 0.5–20 THz. Transmission electron microscopy followed by scanning transmission electron microscopy energy-dispersive spectroscopic (STEM-EDS) analysis was used to confirm the presence of AuSi NS in the cytoplasm or membrane, as single NS or in clusters (22% and 52%, respectively), with the remainder (26%) sequestered in vacuoles. Cellular uptake of NS in response to SS THz radiation could have suitable applications in a vast number of biomedical applications, regenerative medicine, vaccines, cancer therapy, gene and drug delivery.
Publisher: Elsevier BV
Date: 06-2023
Publisher: Elsevier BV
Date: 03-2000
DOI: 10.1016/S1388-2457(99)00296-5
Abstract: The 'aligned-artefact average' (AAA) procedure was advanced by the authors as a technique suitable for removing eye movement-related artefacts from the EEG. It was proposed that this method would correct both blink and non-blink artefact from the EEG, using the same set of correction coefficients (Bs). However, recent evidence suggests that this simplification is not always accurate. Thus, we test here a revision of the AAA, including an appropriate allowance for the radial EOG (REOG) component, that does allow the use of the same Bs for the correction of blink and non-blink artefact. Blink (and saccade) ERP data from 15 subjects were corrected using the AAA method, with Bs calculated from the same blink (and saccade) data set (referent waveforms), or a different set of blink (and saccade) data, or using the new revised AAA procedure (RAAA). AAA Bs calculated from saccades corrected blinks poorly (and vice versa). However, the RAAA Bs corrected blink ERPs better than blink-derived Bs, and saccade ERPs better than saccade-derived Bs. It was also found that irrespective of correction type, inclusion of REOG improved correction. EOG correction is more accurate when the radial channel is included, but inclusion of REOG (and/or HEOG) is not sufficient to resolve the discrepancy between blink and saccade correction. Using the RAAA procedure, both blink and non-blink data can be corrected using the same set of Bs.
Publisher: Elsevier BV
Date: 07-2005
DOI: 10.1016/J.PBB.2005.04.010
Abstract: Working memory impairments in the n-back task in schizophrenia have been linked to sustained deficiency in mesocortical dopamine function. More recently, abnormalities in the cholinergic system have also been documented in schizophrenia, with cortical reductions in both nicotinic and muscarinic receptors. While the cholinergic hypothesis of memory is well established, the role of cholinergic receptors in modulating n-back working memory is not known. We investigated the effects of selective and simultaneous muscarinic and nicotinic antagonism on spatial and object n-back working memory performance. The study was a double-blind, placebo-controlled repeated-measures design in which 12 healthy subjects were tested under four acute treatment conditions placebo (P), mecamylamine (M), scopolamine (S) and mecamylamine+scopolamine (MS). Muscarinic antagonism with scopolamine significantly impaired both object and spatial n-back working memory, whereas nicotinic antagonism with mecamylamine had little effect. Simultaneous antagonism of both muscarinic and nicotinic receptors produced greater impairments in both object and spatial n-back working memory performance than muscarinic or nicotinic antagonism alone. These results suggest that: (1) both muscarinic and nicotinic receptors may functionally interact to synergistically modulate n-back working memory, and (2) that n-back working memory impairments in schizophrenia may in part be due to reductions in both muscarinic and nicotinic receptors.
Publisher: Elsevier BV
Date: 09-1998
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2018
Publisher: Elsevier BV
Date: 2018
DOI: 10.1016/J.SCHRES.2017.05.031
Abstract: Glycine increases N-methyl-d-aspartate receptor (NMDAR) mediated glutamatergic function. Mismatch negativity (MMN) is a proposed biomarker of glutamate-induced improvements in clinical symptoms, however, the effect of glycine-mediated NMDAR activation on MMN in schizophrenia is not well understood. This study aimed to determine the effects of acute and 6-week chronic glycine administration on MMN in schizophrenia patients. MMN litude was compared at baseline between 22 patients (schizophrenia or schizoaffective disorder receiving stable antipsychotic medication multi-centre recruitment) and 21 age- and gender-matched controls. Patients underwent a randomised, double-blind, placebo-controlled clinical trial with glycine added to their regular antipsychotic medication (placebo, n=10 glycine, n=12). MMN was reassessed post-45-minutes of first dose (0.2g/kg) and post-6-weeks treatment (incremented to 0.6g/kg/day). Clinical symptoms were assessed at baseline and post-6-weeks treatment. At baseline, duration MMN was smaller in schizophrenia compared to controls. Acute glycine increased duration MMN (compared to placebo), whilst this difference was absent post-6-weeks treatment. Six weeks of chronic glycine administration improved PANSS-Total, PANSS-Negative and PANSS-General symptoms compared to placebo. Smaller baseline duration MMN was associated with greater PANSS-Negative symptoms and predicted (at trend level) PANSS-Negative symptom improvement post-6-weeks glycine treatment (not placebo). These findings support the benefits of chronic glycine administration and demonstrate, for the first time, that acute glycine improves duration MMN in schizophrenia. This result, together with smaller baseline duration MMN predicting greater clinical treatment response, suggests the potential for duration MMN as a biomarker of glycine-induced improvements in negative symptoms in schizophrenia.
Publisher: Elsevier BV
Date: 08-2016
DOI: 10.1016/J.PSCYCHRESNS.2016.06.011
Abstract: Schizophrenia may be conceptualised using a dimensional approach to examine trait-like expression such as schizotypy within non-clinical populations to better understand pathophysiology. A candidate psychosis-risk marker, the auditory mismatch negativity (MMN) is thought to index the functionality of glutamatergic NMDA receptor mediated neurotransmission. Although the MMN is robustly reduced in patients with schizophrenia, the association between MMN and schizotypy in the general population is under-investigated. Thirty-five healthy participants completed the Schizotypal Personality Questionnaire (SPQ) and a multi-feature MMN paradigm (standards 82%, 50ms, 1000Hz, 80dB) with duration (100ms), frequency (1200Hz) and intensity (90dB) deviants (6% each). Spearman's correlations were used to explore the association between schizotypal personality traits and MMN litude. Few associations were identified between schizotypal traits and MMN. Higher Suspiciousness subscale scores tended to be correlated with larger frequency MMN litude. A median-split comparison of the s le on Suspiciousness scores showed larger MMN (irrespective of deviant condition) in the High compared to the Low Suspiciousness group. The trend-level association between MMN and Suspiciousness is in contrast to the robustly attenuated MMN litude observed in schizophrenia. Reductions in MMN may reflect a schizophrenia-disease state, whereas non-clinical schizotypy may not be subserved by similar neuropathology.
Publisher: The Royal Society
Date: 06-2022
DOI: 10.1098/RSOS.220520
Abstract: Exposure to high-frequency (HF) electromagnetic fields (EMFs) at 18 GHz was previously found to induce reversible cell permeabilization in eukaryotic cells however, the fate of internalized foreign objects inside the cell remains unclear. Here, silica core–shell gold nanospheres (Au NS) of 20 ± 5 nm diameter were used to study the localization of Au NS in pheochromocytoma (PC 12) cells after exposure to HF EMFs at 18 GHz. Internalization of Au NS was confirmed using fluorescence microscopy and transmission electron microscopy. Analysis based on corresponding scanning transmission electron microscopy energy-dispersive spectroscopy revealed the presence of the Au NS free within the PC 12 cell membrane, cytoplasm, enclosed within intracellular vesicles and sequestered in vacuoles. The results obtained in this work highlight that exposure to HF EMFs could be used as an efficient technique with potential for effective delivery of drugs, genetic material, and nanomaterials into cells for the purpose of cellular manipulation or therapy.
Publisher: Wiley
Date: 2008
DOI: 10.1002/HUP.922
Abstract: The underlying effect of serotonergic neurotransmission has been implicated in several psychiatric disorders. The inability to routinely and non-invasively determine the integrity of the serotonergic system in vivo has limited our understanding of disorders with a putative serotonergic abnormality. The loudness dependence of the auditory evoked potential (LDAEP) has been proposed as a reliable measure of central serotonin function in humans. While animal studies suggest that the LDAEP is sensitive to changes in central serotonin neurotransmission, evidence in humans has been indirect and inconsistent. The aim of this study was to assess the sensitivity of the LDAEP to acute augmentation in central serotonergic neurotransmission in humans. The study used a double-blind, placebo-controlled cross-over design, in which healthy subjects were tested under four acute treatment conditions, with pharmacologically equivalent single doses of placebo, escitalopram (10 mg), citalopram (20 mg) and sertraline (50 mg) to examine the direct effect of acute enhancement of synaptic serotonin on the LDAEP. Furthermore, the outcome of the serotonergic modulatory effects on the LDAEP was also examined using two methods (dipole source analysis (DSA) vs. scalp analysis). Escitalopram, citalopram and sertraline had no effects on the LDAEP and were independent of the analysis method used. These findings question the sensitivity of the LDAEP to acute changes in serotonin neurotransmission and its validity as a reliable measure of central serotonin function in humans.
Publisher: MDPI AG
Date: 08-07-2019
Abstract: Previous epidemiological studies on health effects of radiation exposure from mobile phones have produced inconsistent results. This may be due to experimental difficulties and various sources of uncertainty, such as statistical variability, measurement errors, and model uncertainty. An analytical technique known as the Monte Carlo simulation provides an additional approach to analysis by addressing uncertainty in model inputs using error probability distributions, rather than point-source data. The aim of this investigation was to demonstrate using Monte Carlo simulation of data from the ExPOSURE (Examination of Psychological Outcomes in Students using Radiofrequency dEvices) study to quantify uncertainty in the output of the model. Data were collected twice, approximately one year apart (between 2011 and 2013) for 412 primary school participants in Australia. Monte Carlo simulation was used to estimate output uncertainty in the model due to uncertainties in the call exposure data. Multiple linear regression models evaluated associations between mobile phone calls with cognitive function and found weak evidence of an association. Similar to previous longitudinal analysis, associations were found for the Go/No Go and Groton maze learning tasks, and a Stroop time ratio. However, with the introduction of uncertainty analysis, the results were closer to the null hypothesis.
Publisher: Frontiers Media SA
Date: 2013
Publisher: Elsevier BV
Date: 10-2005
DOI: 10.1016/J.IJPSYCHO.2005.03.004
Abstract: This study investigated the effects of methylphenidate on intrahemispheric and interhemispheric EEG coherence in children with Attention-Deficit/Hyperactivity Disorder (AD/HD). Twenty boys with AD/HD Combined type and 20 age- and sex-matched control subjects, aged 8 to 13 years, participated in this study. EEG was recorded from 21 sites during an eyes-closed resting condition. Wave-shape coherence was calculated for eight intrahemispheric electrode pairs (four in each hemisphere), and eight interhemispheric electrode pairs, within each of the delta, theta, alpha and beta bands. AD/HD children were tested both off and, 6 months later, on a therapeutic dose of methylphenidate. In intrahemispheric comparisons, AD/HD children had lower theta coherences at long inter-electrode distances, and reduced lateralisation at both long and short-medium inter-electrode distances than controls. For interhemispheric comparisons, AD/HD children showed increased coherences in the frontal regions for the low frequency bands (delta and theta), and reduced coherences in the alpha bands in all other regions. These EEG coherences suggest reduced cortical differentiation and specialisation in AD/HD, particularly in the frontal regions. Methylphenidate did not produce any changes in coherence values. The lack of sensitivity of coherence measures to methylphenidate in the present study suggests that eyes-closed resting EEG coherence measures are associated with structural connectivity of the underlying regions of the brain rather than the degree of functionality of these regions. These results suggest the existence of structural as well as functional brain dysfunction in AD/HD.
Publisher: Springer Science and Business Media LLC
Date: 27-01-2011
DOI: 10.1007/S11682-011-9115-6
Abstract: Sleep loss, widespread in today's society and associated with a number of clinical conditions, has a detrimental effect on a variety of cognitive domains including attention. This study examined the sequelae of sleep deprivation upon BOLD fMRI activation during ided attention. Twelve healthy males completed two randomized sessions one after 27 h of sleep deprivation and one after a normal night of sleep. During each session, BOLD fMRI was measured while subjects completed a cross-modal ided attention task (visual and auditory). After normal sleep, increased BOLD activation was observed bilaterally in the superior frontal gyrus and the inferior parietal lobe during ided attention performance. Subjects reported feeling significantly more sleepy in the sleep deprivation session, and there was a trend towards poorer ided attention task performance. Sleep deprivation led to a down regulation of activation in the left superior frontal gyrus, possibly reflecting an attenuation of top-down control mechanisms on the attentional system. These findings have implications for understanding the neural correlates of ided attention and the neurofunctional changes that occur in in iduals who are sleep deprived.
Publisher: Mary Ann Liebert Inc
Date: 08-2002
DOI: 10.1089/107555302760253621
Abstract: Exposure to active mobile phones (MP) has been shown to affect human neural function as shown by the electroencephalogram (EEG). Although it has not been determined whether such effects are harmful, a number of devices have been developed that attempt to minimize these MP-related effects. One such device, the Q Link Ally (QL Clarus Products, International, L.L.C., San Rafael, CA), is argued to affect the human organism in such a way as to attenuate the effect of MPs. The present pilot study was designed to determine whether there is any indication that QL does alter MP-related effects on the human EEG. Twenty-four (24) subjects participated in a single-blind, fully counterbalanced crossover design in which subjects' resting EEG and phase-locked neural responses to auditory stimuli were assessed under conditions of either active MP or active MP plus QL. The addition of QL to the MP condition increased resting EEG in the gamma range and did so as a function of exposure duration, and it attenuated MP-related effects in the delta and alpha range (at trend-level). The addition of the QL also affected phase-locked neural responses, with a laterality reversal in the alpha range and an alteration to changes over time in the delta range, a reduction of the MP-related beta decrease over time at fronto-posterior sites, and a global reduction in the gamma range that increased as a function of exposure duration. No unambiguous relations were found between these changes and either performance or psychologic state. This pilot study suggests that the addition of the QL to active MP-exposure does affect neural function in humans, altering both resting EEG patterns and the evoked neural response to auditory stimuli, and that there is a tendency for some MP-related changes to the EEG to be attenuated by the QL.
Publisher: Wiley
Date: 2008
DOI: 10.1002/HUP.926
Abstract: The loudness dependence of the auditory evoked potential (LDAEP) has been suggested as a possible in vivo measure of central serotonin function. However, more recent studies suggest that the LDAEP may be modulated by multiple neuromodulatory systems in addition to the serotonergic system. Accordingly we further examined the effects of selective serotonin, dopamine and simultaneous serotonin and dopamine depletion on the LDAEP in healthy subjects. The study employed a placebo-controlled, double-blind, cross over design. Fourteen subjects were tested under four acute treatment conditions: placebo (balanced amino acid drink), tryptophan (serotonin) depletion (ATD), tyrosine henylalanine (dopamine) depletion (ATPD) and combined tryptophan/tyrosine henylalanine (serotonin and dopamine) depletion (CMD). Testing was conducted 5.5 h post-depletion and changes in the litude of the N1/P2 at varying intensities (60, 70, 80, 90, 100 dB) were examined at C(Z). Greater than 80% plasma precursor depletion was achieved across all conditions. Despite significant depletion of monoamine precursors, ATD, (p = 0.318), ATPD (p = 0.061) and CMD (p = 0.104) had no effects on the LDAEP (60-100 dB). Acute serotonin and dopamine depletion did not modulate the LDAEP. This finding adds support to growing evidence that the LDAEP is insensitive to acute changes in serotonin and dopamine neurotransmission.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2006
DOI: 10.1097/01.WNR.0000198433.29389.54
Abstract: This study sought to explore whether the so-called 'paradoxical' task-related increases in the alpha bandwidth of the human electroencephalogram result from increases in evoked (phase locked), as opposed to induced (non-phase locked), activity. The electroencephalograms of 18 participants were recorded while they engaged in both auditory sensory-intake tasks (listening to randomly generated 'tunes') and internally directed attention tasks (imagining the same randomly generated tunes) matched for auditory input. Measures of evoked (phase locked) and induced (non-phase locked) activity were compared between tasks. Increases in induced alpha power were found during internal attention. No experimental effects were observed for evoked activity. These results are not entirely consistent with proposals that 'paradoxical' alpha indexes the evoked inhibition of task irrelevant processing.
Publisher: Springer Science and Business Media LLC
Date: 11-05-2022
DOI: 10.1038/S41598-022-11755-Y
Abstract: Inconsistencies have been found in the relationship between ambient lighting conditions and frequency-dependence in transcranial electric stimulation (tES) induced phosphenes. Using a within-subjects design across lighting condition (dark, mesopic [dim], photopic [bright]) and tES stimulation frequency (10, 13, 16, 18, 20 Hz), this study determined phosphene detection thresholds in 24 subjects receiving tES using an FPz-Cz montage. Minima phosphene thresholds were found at 16 Hz in mesopic, 10 Hz in dark and 20 Hz in photopic lighting conditions, with these thresholds being substantially lower for mesopic than both dark (60% reduction) and photopic (56% reduction), conditions. Further, whereas the phosphene threshold-stimulation frequency relation increased with frequency in the dark and decreased with frequency in the photopic conditions, in the mesopic condition it followed the dark condition relation from 10 to 16 Hz, and photopic condition relation from 16 to 20 Hz. The results clearly demonstrate that ambient lighting is an important factor in the detection of tES-induced phosphenes, and that mesopic conditions are most suitable for obtaining overall phosphene thresholds.
Publisher: Elsevier BV
Date: 11-2014
Publisher: Springer Science and Business Media LLC
Date: 05-07-2007
DOI: 10.1007/S00213-007-0865-1
Abstract: Schizophrenia is commonly associated with an impairment in pre-attentive change detection, as represented by reduced mismatch negativity (MMN), an auditory event related potential. While the neurochemical basis of MMN has been linked to the integrity of the glutamatergic system involving N-methyl-D-aspartate (NMDA) receptors, the role of the dopaminergic system and in particular, the role of D(1) and D(2) receptors on MMN is yet to be determined. The aim of the present project was to investigate the acute effects of dopamine D(2) (bromocriptine) and D(1)/D(2) (pergolide) receptor stimulation on the human MMN in healthy subjects. Fifteen healthy male subjects participated in a double-blind, placebo-controlled, cross-over design in which each subject was tested under three acute treatment conditions separated by a 1-week wash out period placebo, bromocriptine (2.5 mg) and pergolide (0.1 mg). The subjects were exposed to a duration-MMN paradigm with 50 ms standard tones (91%) and 100 ms deviant tones (9%). The results showed that neither D(2) receptor stimulation with bromocriptine, nor simultaneous D(1) and D(2) receptor stimulation with pergolide, modulated MMN. These findings suggest that acute D(1) and D(2) receptor stimulation does not modulate MMN. While the role of dopamine cannot be completely ruled out, the findings support the view that the aberrant MMN reported in schizophrenia may be linked primarily to glutamate dysfunction involving NMDA receptors.
Publisher: Elsevier BV
Date: 10-2002
DOI: 10.1016/S1388-2457(02)00215-8
Abstract: Mobile phones (MP) are used extensively and yet little is known about the effects they may have on human physiology. There have been conflicting reports regarding the relation between MP use and the electroencephalogram (EEG). The present study suggests that this conflict may be due to methodological differences such as exposure durations, and tests whether exposure to an active MP affects EEG as a function of time. Twenty-four subjects participated in a single-blind fully counterbalanced cross-over design, where both resting EEG and phase-locked neural responses to auditory stimuli were measured while a MP was either operating or turned off. MP exposure altered resting EEG, decreasing 1-4 Hz activity (right hemisphere sites), and increasing 8-12 Hz activity as a function of exposure duration (midline posterior sites). MP exposure also altered early phase-locked neural responses, attenuating the normal response decrement over time in the 4-8 Hz band, decreasing the response in the 1230 Hz band globally and as a function of time, and increasing midline frontal and lateral posterior responses in the 30-45 Hz band. Active MPs affect neural function in humans and do so as a function of exposure duration. The temporal nature of this effect may contribute to the lack of consistent results reported in the literature.
Publisher: Springer Science and Business Media LLC
Date: 19-10-2006
Abstract: The sex steroid hormone, estrogen, has been proposed to be protective against schizophrenia. This study examined the effects of estrogen treatment on modulation of prepulse inhibition (PPI) by the serotonin-1A (5-HT1A) receptor partial agonist, buspirone. PPI is a model of sensorimotor gating, which is deficient in schizophrenia and other mental illnesses. A total of 11 healthy women were tested following four acute treatment conditions: placebo, buspirone (Buspar 5 mg), estradiol (Estrofem 2 mg), and combined buspirone and estradiol. Electromyogram activity was measured across three interstimulus intervals (ISI): 30, 60, and 120 ms. There was no significant effect of either drug treatment on startle litude or habituation. At 120 ms ISI, buspirone caused a significant disruption of PPI and pretreatment with estrogen prevented this disruption. Estrogen treatment, administered in the appropriate experimental conditions, prevented PPI deficits induced by 5-HT(1A) receptor activation and may therefore also play a protective role in sensorimotor gating deficits in schizophrenia.
Publisher: Springer Science and Business Media LLC
Date: 12-2007
DOI: 10.1007/BF03178437
Publisher: Springer Science and Business Media LLC
Date: 08-06-2006
DOI: 10.1007/S00213-006-0410-7
Abstract: It is not clear how the deleterious effects of hetamines on driving performance are mediated in terms of select cognitive processes. The current three separate experiments assessed the acute effects of an oral dose of either 0.42-mg/kg d- hetamine, d,l-meth hetamine and d-meth hetamine on driving-related cognitive functions in a total of 60 healthy non-fatigued adults. Three separate repeated measures counterbalanced, double-blind, placebo-controlled designs were employed in which 20 volunteers completed two treatment conditions, either d- hetamine, d,l-meth hetamine or d-meth hetamine and placebo. Performance was assessed on a range of attentional, psychomotor and perceptual speed tasks. Mean blood concentrations at 120-, 170- and 240-min postdrug administration were 83, 98 and 96 ng/ml, respectively, for d- hetamine, 90, 95 and 105 ng/ml, respectively, for d,l-meth hetamine and 72, 67 and 59 ng/ml, respectively, for d-meth hetamine. The hetamines, in general, improved various aspects of attention (Digit Vigilance, Digit Symbol Substitution Test and Movement Estimation Performance) with some evidence to suggest possible enhancement in psychomotor functioning (Tracking ability) and perceptual speed (Inspection Time). The current series of studies primarily provides evidence of low-level hetamine-related enhancement of function however, it also provides evidence of less conservative movement estimation that might contribute to hetamine-related road fatalities.
Publisher: Elsevier BV
Date: 03-2004
DOI: 10.1016/S0920-9964(03)00132-4
Abstract: Mismatch negativity (MMN) is a measure of cortical activity that occurs in response to a change in auditory stimuli. We investigated whether MMN is a potential marker of genetic vulnerability to schizophrenia by comparing MMN in a group of patients with schizophrenia, their unaffected relatives, and controls. There are 25 schizophrenic patients, 37 of their unaffected first-degree relatives, and 20 unrelated controls that performed the MMN task. Linear regression with robust standard errors, and accounting for correlations within families, was employed to test for differences in MMN litude between the groups. Patients had significantly smaller MMN litudes compared to both their unaffected relatives and controls at FZ (P<0.01) and at F3 (P=0.01), whereas relatives and controls did not differ at FZ or at F3. No differences were found between any of the groups at F4. Furthermore, we found no strong evidence that the MMN litude is a familial trait. Our results confirm that the MMN litude is reduced in schizophrenia. However, the MMN does not show a significant familial influence and is normal among the unaffected relatives. We conclude that while the MMN is abnormal in patients with schizophrenia, it is a weak or unreliable marker of vulnerability when applied to subclinical populations, and therefore is unlikely to be an endophenotype for the disorder.
Publisher: SAGE Publications
Date: 11-2006
Publisher: Humana Press
Date: 2008
Publisher: Wiley
Date: 03-2012
DOI: 10.1002/HUP.1238
Abstract: Meth hetamine is considered to be one of the most popularly abused drugs by drivers however, its exact effect on driving and driving behaviour has yet to be thoroughly investigated. This being despite meth hetamine's increased prevalence in injured and deceased drivers. Twenty healthy recreational illicit stimulant users (10 male and 10 female), aged between 21 and 32 years (mean = 25.4 years, SD = 3.3 years) attended two testing sessions involving oral consumption of 0.42 mg/kg d-meth hetamine or a matching placebo. The drug administration was counter-balanced, double-blind, and medically supervised. At each session driving, performance was assessed 2.5 h post drug administration. d-meth hetamine (0.42 mg/kg) did not significantly impair overall simulated driving performance 2.5 h post drug administration. At the in idual driving variable level, participants in the d-meth hetamine condition were observed to be driving slower when an emergency situation occurred (T = 44, p < 0.05), but interestingly, participants in both conditions recorded average speeds in excess of the speed limit (100 km/h) when the emergency situations occurred. The d-meth hetamine condition did also produce four times more infringements where participants did not stop at red traffic light in comparison to the placebo, but this effect was only evident at a trend level (T = 7, p = 0.11). The findings presented herein suggest that d-meth hetamine administered at the levels supplied did not impair driving performance in a manner consistent with epidemiological evidence. Further research is certainly required to elucidate the effects of various doses of meth hetamine, alone and in combination with other legal and illicit substances.
Publisher: MDPI AG
Date: 12-10-2018
Abstract: The measurement of personal exposure to radiofrequency electromagnetic fields (RF-EMFs) is important for epidemiological studies. RF-EMF exposure can be measured using personal exposimeters that register RF-EMFs over a wide range of frequency bands. This study aimed to measure and describe personal RF-EMF exposure levels from a wide range of frequency bands. Measurements were recorded from 63 participants over an average of 27.4 (±4.5) hours. RF-EMF exposure levels were computed for each frequency band, as well as from downlink (RF from mobile phone base station), uplink (RF from mobile phone handsets), broadcast, and Wi-Fi. Participants had a mean (±SD) age of 36.9 ± 12.5 years 66.7% were women and almost all (98.2%) from urban areas. A Wi-Fi router at home was reported by 61 participants (96.8%), with 38 (61.2%) having a Wi-Fi enabled smart TV. Overall, 26 (41.3%) participants had noticed the existence of a mobile phone base station in their neighborhood. On average, participants estimated the distance between the base station and their usual residence to be about 500 m. The median personal RF-EMF exposure was 208 mV/m. Downlink contributed 40.4% of the total RF-EMF exposure, followed by broadcast (22.4%), uplink (17.3%), and Wi-Fi (15.9%). RF-EMF exposure levels on weekdays were higher than weekends (p 0.05). Downlink and broadcast are the main contributors to total RF-EMF personal exposure. Personal RF-EMF exposure levels vary according to day of the week and time of day.
Publisher: Elsevier BV
Date: 07-2007
DOI: 10.1016/J.CLINPH.2007.04.006
Abstract: This study investigated differences in coherence measures between two groups of children with Attention-Deficit/Hyperactivity Disorder (ADHD) - with the typical EEG profile (increased theta and decreased beta activity), and with excess beta activity - and a normal control group. Thirty-four children with ADHD were included in each of the typical and excess beta groups, and were age and sex matched with 34 control subjects. EEG was recorded from 21 sites during an eyes-closed resting condition. Wave-shape coherence was calculated for eight intrahemispheric and eight interhemispheric electrode pairs, for the delta, theta, alpha and beta bands. In comparison to the controls, the typical ADHD group primarily had increased intrahemispheric theta and beta coherence at short-medium inter-electrode distances, and increased interhemispheric coherence for theta in the frontal and central arietal/occipital regions. Their laterality effect for interhemispheric short-medium inter-electrode distances was reduced in the theta band. Differences between the excess beta group and the control group were primarily found in laterality of the intrahemispheric theta coherence at short-medium electrode distances, and increased interhemispheric theta coherence in the frontal regions. Reduced delta coherence in the temporal regions was also found. These results suggest that ADHD children with excess beta power have an underlying brain dysfunction in the frontal lobes which is found in common with children with the typical EEG profile. However a number of qualitative differences exist which could be associated with other aspects of the ADHD diagnosis or another comorbid condition. This is the first study to investigate EEG coherence in ADHD children who have increased beta power.
Publisher: Elsevier BV
Date: 09-2009
DOI: 10.1016/J.IJPSYCHO.2009.05.003
Abstract: We examined relationships between the phase of narrow-band electroencephalographic (EEG) activity at stimulus onset and the resultant event-related potentials (ERPs) in an auditory oddball task, varying both stimulus intensity and active vs. passive task requirements between groups. We used a novel conceptualisation of orthogonal phase effects (cortical negativity vs. positivity, negative driving vs. positive driving, waxing vs. waning). This study focused on the operation of three previously-reported phase-influenced mechanisms, involving prestimulus litudes, poststimulus litude changes, and the prestimulus contingent negative variation (CNV), in various EEG frequency bands. ERP responses to the standard stimuli were analysed. Prestimulus narrow-band EEG activity (in 1 Hz bands from 1 to 13 Hz) at Cz was assessed for each trial using digital filtering. For each frequency, the cycle at stimulus onset was used to sort trials into four phases, for which ERPs were derived from both the filtered and unfiltered EEG activity at Fz, Cz, and Pz. The occurrence of preferred phase-defined brain states was confirmed at a number of frequencies, crossing the traditional frequency bands. These preferred states were associated with more efficient processing of the stimulus, as reflected in differences in latency and/or litude of all ERP components, and provided evidence of the operation of the three separate phase-influenced mechanisms. The preferred brain states occurred similarly across groups, suggesting that they reflect reflexive aspects of brain function associated with the timing of the stimuli, rather than voluntary attention. The impact on markers of cognitive function, such as the P3, suggests their important contributions to the efficiency of brain dynamics involved in perceptual and cognitive processing.
Publisher: Elsevier BV
Date: 10-2007
DOI: 10.1016/J.CLINPH.2007.06.059
Abstract: We aimed to examine relationships between the phase of narrow-band electroencephalographic (EEG) activity at stimulus onset and the resultant event-related potentials (ERPs) in active vs. passive auditory oddball tasks, using a novel conceptualisation of orthogonal phase effects. This study focused on the operation of three recently-reported phase-influenced mechanisms, and ERP responses to the standard stimuli were analysed. Prestimulus narrow-band EEG activity (in 1 Hz bands from 1 to 13 Hz) at Cz was assessed for each trial using digital filtering. For each frequency, the cycle at stimulus onset was used to sort trials into four phases, for which ERPs were derived from both the filtered and unfiltered EEG activity at Fz, Cz and Pz. Preferred brain states at various frequencies were indicated by approximately 20% differential occurrence within the orthogonal phase dimensions explored. The preferred states were associated with more efficient processing of the stimulus, as reflected in differences in latency and/or litude of various ERP components, and provided evidence for the operation of the three separate phase-influenced mechanisms. Both the occurrence of preferred brain states, and the mechanisms linking them to ERP outcomes focused on here, appeared relatively invariant across tasks, suggesting that they largely reflect reflexive brain processes.
Publisher: Informa UK Limited
Date: 24-09-2016
DOI: 10.1080/00140139.2015.1082632
Abstract: Motorcycle protective clothing can be uncomfortably hot during summer, and this experiment was designed to evaluate the physiological significance of that burden. Twelve males participated in four, 90-min trials (cycling 30 W) across three environments (25, 30, 35 °C [all 40% relative humidity]). Clothing was modified between full and minimal injury protection. Both ensembles were tested at 25 °C, with only the more protective ensemble investigated at 30 and 35 °C. At 35 °C, auditory canal temperature rose at 0.02 °C min(-1) (SD 0.005), deviating from all other trials (p 38.5 °C) and profound hyperthermia (>40.0 °C) were predicted to occur within 105 min (SD 20.6) and 180 min (SD 33.0), respectively. Profound hyperthermia might eventuate in ~10 h at 30 °C, but should not occur at 25 °C. These outcomes demonstrate a need to enhance the heat dissipation capabilities of motorcycle clothing designed for summer use in hot climates, but without compromising impact protection. Practitioner's Summary: Motorcycle protective clothing can be uncomfortably hot during summer. This experiment was designed to evaluate the physiological significance of this burden across climatic states. In the heat, moderate (>38.5 °C) and profound hyperthermia (>40.0 °C) were predicted to occur within 105 and 180 min, respectively.
Publisher: Springer Science and Business Media LLC
Date: 11-2021
DOI: 10.1007/S00213-021-05997-3
Abstract: Mismatch negativity (MMN) is a candidate endophenotype for schizophrenia subserved by N-methyl-D-aspartate receptor (NMDAR) function and there is increasing evidence that prolonged cannabis use adversely affects MMN generation. Few human studies have investigated the acute effects of cannabinoids on brain-based biomarkers of NMDAR function and synaptic plasticity. The current study investigated the acute effects of Δ In a randomised, double-blind, crossover placebo-controlled study, 18 frequent and 18 less-frequent cannabis users underwent 5 randomised drug sessions administered via vaporiser: (1) placebo (2) THC 8 mg (3) CBD 400 mg (4) THC 8 mg + CBD 4 mg [THC + CBD Relative to placebo, both THC and CBD were observed to increase duration and intensity MMN litude in less-frequent users, and THC also increased frequency MMN in this group. The addition of low-dose CBD added to THC attenuated the effect of THC on duration and intensity MMN litude in less-frequent users. The same pattern of effects was observed following high-dose CBD added to THC on duration and frequency MMN in frequent users. The pattern of effects following CBD combined with THC on MMN may be subserved by different underlying neurobiological interactions within the endocannabinoid system that vary as a function of prior cannabis exposure. These results highlight the complex interplay between the acute effects of exogenous cannabinoids and NMDAR function. Further research is needed to determine how this process normalises after the acute effects dissipate and following repeated acute exposure.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 28-11-2005
DOI: 10.1097/01.WNR.0000186593.79705.3C
Abstract: Previous research has suggested that exposure to radiofrequency electromagnetic fields increases electroencephalogram spectral power in non-rapid eye movement sleep. Other sleep parameters have also been affected following exposure. We examined whether aspects of sleep architecture show sensitivity to electromagnetic fields emitted by digital mobile phone handsets. Fifty participants were exposed to electromagnetic fields for 30 min prior to sleep. Results showed a decrease in rapid eye movement sleep latency and increased electroencephalogram spectral power in the 11.5-12.25 Hz frequency range during the initial part of sleep following exposure. These results are evidence that mobile phone exposure prior to sleep may promote rapid eye movement sleep and modify the sleep electroencephalogram in the first non-rapid eye movement sleep period.
Publisher: Springer Science and Business Media LLC
Date: 19-02-2016
Publisher: Elsevier BV
Date: 03-2013
DOI: 10.1016/J.BIOPSYCH.2013.05.035
Abstract: Cannabis use is associated with the development of psychotic symptoms and increased risk for schizophrenia. The mismatch negativity (MMN) is a brain event-related potential marker of change detection thought to index glutamatergic N-methyl-D-aspartate receptor-mediated neurotransmission, which is known to be deficient in schizophrenia. This study examined auditory MMN in otherwise healthy chronic cannabis users compared with nonuser control subjects. Forty-two chronic cannabis users and 44 nonuser healthy control subjects completed a multi-feature MMN paradigm, which included duration, frequency, and intensity deviants (deviants 6% standards 82%). The MMN was compared between users and control subjects as well as between long- and short-term users and age- and gender-matched control subjects. Associations between MMN, cannabis use measures, and symptoms were examined. The MMN litude was significantly reduced to frequency but not duration or intensity deviants in overall cannabis users relative to control subjects. Frequency MMN was similarly attenuated in short- and long-term users relative to control subjects. Long-term users also exhibited reduced duration MMN relative to control subjects and short-term users and this was correlated with increased duration of exposure to cannabis and increased psychotic-like experiences during intoxication. In short-term users, a younger age of onset of regular cannabis use and greater frequency of use were associated with greater psychotic-like experiences and symptomatic distress. These results suggest impaired sensory memory that might reflect N-methyl-D-aspartate receptor dysfunction in chronic cannabis users. The pattern of MMN alterations in cannabis users differed from that typically observed in patients with schizophrenia, indicating overlapping but distinct underlying pathology.
Publisher: BMJ
Date: 12-2018
DOI: 10.1136/BMJOPEN-2018-024489
Abstract: Some studies have reported increasing trends in certain brain tumours and a possible link with mobile phone use has been suggested. We examined the incidence time trends of brain tumour in Australia for three distinct time periods to ascertain the influence of improved diagnostic technologies and increase in mobile phone use on the incidence of brain tumours. In a population-based ecological study, we examined trends of brain tumour over the periods 1982–1992, 1993–2002 and 2003–2013. We further compared the observed incidence during the period of substantial mobile phone use (2003–2013) with predicted (modelled) incidence for the same period by applying various relative risks, latency periods and mobile phone use scenarios. National Australian incidence registration data on primary cancers of the brain diagnosed between 1982 and 2013. 16 825 eligible brain cancer cases aged 20–59 from all of Australia (10 083 males and 6742 females). Annual percentage change (APC) in brain tumour incidence based on Poisson regression analysis. The overall brain tumour rates remained stable during all three periods. There was an increase in glioblastoma during 1993–2002 (APC 2.3, 95% CI 0.8 to 3.7) which was likely due to advances in the use of MRI during that period. There were no increases in any brain tumour types, including glioma (−0.6, –1.4 to 0.2) and glioblastoma (0.8, –0.4 to 2.0), during the period of substantial mobile phone use from 2003 to 2013. During that period, there was also no increase in glioma of the temporal lobe (0.5, –1.3 to 2.3), which is the location most exposed when using a mobile phone. Predicted incidence rates were higher than the observed rates for latency periods up to 15 years. In Australia, there has been no increase in any brain tumour histological type or glioma location that can be attributed to mobile phones.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2020
DOI: 10.1097/HP.0000000000001210
Abstract: Radiofrequency electromagnetic fields (EMFs) are used to enable a number of modern devices, including mobile telecommunications infrastructure and phones, Wi-Fi, and Bluetooth. As radiofrequency EMFs at sufficiently high power levels can adversely affect health, ICNIRP published Guidelines in 1998 for human exposure to time-varying EMFs up to 300 GHz, which included the radiofrequency EMF spectrum. Since that time, there has been a considerable body of science further addressing the relation between radiofrequency EMFs and adverse health outcomes, as well as significant developments in the technologies that use radiofrequency EMFs. Accordingly, ICNIRP has updated the radiofrequency EMF part of the 1998 Guidelines. This document presents these revised Guidelines, which provide protection for humans from exposure to EMFs from 100 kHz to 300 GHz.
Publisher: Wiley
Date: 27-07-2016
DOI: 10.1002/BRB3.511
Publisher: Informa UK Limited
Date: 30-11-2009
DOI: 10.1080/10937400903458940
Abstract: The effects of exposure to radiofrequency electromagnetic fields (EMF), specifically related to the use of mobile telephones, on the nervous system in humans have been the subject of a large number of experimental studies in recent years. There is some evidence of an effect of exposure to a Global System for Mobile Telecommunication (GSM)-type signal on the spontaneous electroencephalogram (EEG). This is not corroborated, however, by the results from studies on evoked potentials. Although there is some evidence emerging that there may be an effect of exposure to a GSM-type signal on sleep EEG, results are still variable. In summary, exposure to a GSM-type signal may result in minor effects on brain activity, but such changes have never been found to relate to any adverse health effects. No consistent significant effects on cognitive performance in adults have been observed. If anything, any effect is small and exposure seems to improve performance. Effects in children did not differ from those in healthy adults. Studies on auditory and vestibular function are more unequivocal: neither hearing nor the sense of balance is influenced by short-term exposure to mobile phone signals. Subjective symptoms over a wide range, including headaches and migraine, fatigue, and skin itch, have been attributed to various radiofrequency sources both at home and at work. However, in provocation studies a causal relation between EMF exposure and symptoms has never been demonstrated. There are clear indications, however, that psychological factors such as the conscious expectation of effect may play an important role in this condition.
Publisher: Wiley
Date: 12-2009
DOI: 10.1002/BEM.20534
Abstract: As part of the Mobile Radiofrequency Phone Exposed Users' Study (MoRPhEUS), a cross-sectional epidemiological study examined cognitive function in secondary school students. We recruited 317, 7th grade students (144 boys, 173 girls, median age 13 years) from 20 schools around Melbourne, Australia. Participants completed an exposure questionnaire based on the Interphone study, a computerised cognitive test battery, and the Stroop colour-word test. The principal exposure metric was the total number of reported mobile phone voice calls per week. Linear regression models were fitted to cognitive test response times and accuracies. Age, gender, ethnicity, socio-economic status and handedness were fitted as covariates and standard errors were adjusted for clustering by school. The accuracy of working memory was poorer, reaction time for a simple learning task shorter, associative learning response time shorter and accuracy poorer in children reporting more mobile phone voice calls. There were no significant relationships between exposure and signal detection, movement monitoring or estimation. The completion time for Stroop word naming tasks was longer for those reporting more mobile phone voice calls. The findings were similar for total short message service (SMS, also known as text) messages per week, suggesting these cognitive changes were unlikely due to radiofrequency (RF) exposure. Overall, mobile phone use was associated with faster and less accurate responding to higher level cognitive tasks. These behaviours may have been learned through frequent use of a mobile phone.
Publisher: MDPI AG
Date: 09-10-2016
Publisher: Aerospace Medical Association
Date: 02-2021
Abstract: BACKGROUND: Ischemic hypoxia induced by suprathreshold G-force loading can adversely affect vision, cognition, and lead to loss of consciousness (LOC). The purpose of this study was to determine whether reductions in cerebral oxygenation, caused by subthreshold G-forces (up to 4 G z and of limited durations that do not lead to LOC), would affect visual perception and working memory performance. METHODS: Sixteen subjects performed visual perception and working memory tasks both before and during G z exposures (1, 2.2, 3, 4 with leg pressurization, 4 with leg and abdomen pressurization) within a human-use centrifuge. RESULTS: As measured using near-infrared spectroscopy, blood oxygenation over medial prefrontal cortex was similar in the 1 and 2.2 G z conditions, but was reduced to a similar extent in the 3 and 4 G z conditions. In parallel, visual perception accuracy was reduced in the 3 and 4 G z conditions, with no difference between the 3 and 4 G z conditions. No change in reaction time was seen. Conversely, neither accuracy nor reaction time changes were observed for the visual working memory task. DISCUSSION: These results indicate that although visual working memory is not affected, the ability to visually discriminate between stimuli is reduced at G-forces as low as 3 and 4 G z . This may have important ramifications for pilots who are routinely subjected to such forces. Croft RJ, Klegrd R, Tribukait A, Taylor NAS, Eiken O. Effects of acceleration-induced reductions in retinal and cerebral oxygenation on human performance. Aerosp Med Hum Perform. 2021 92(2):7582.
Publisher: Wiley
Date: 09-12-2010
DOI: 10.1111/J.1469-8986.2010.01036.X
Abstract: A means of accounting for ocular artifact in the electroencephalograph (EEG) is to subtract portions (Bs) of ocular voltage measured by the electrooculograph (EOG) from the EEG. Some such EOG correction methods calculate Bs at one time and use these to correct data recorded at a different time these require information about the temporal stability of the Bs. This study investigated the stability of Bs over a 2-hr EEG recording session. Participants performed 5 eye movement tasks, each separated by 30 min. Four EOG correction methods were then used to calculate Bs from each of the 5 data sets, resulting in VEOG, HEOG, and REOG (where appropriate) Bs for each methods at each of the 5 time points. We did not find evidence that Bs changed over the 2-hr period, nor of any difference in temporal stability between the methods. This study suggests that it is appropriate to employ Bs calculated from calibration trials to correct data recorded within at least a 2-hr time window.
Publisher: Elsevier BV
Date: 09-1998
Publisher: Elsevier BV
Date: 11-2008
DOI: 10.1016/J.YHBEH.2008.07.007
Abstract: The steroid hormone estradiol has been shown to modulate cognitive function in both animals and humans, and although the exact mechanisms associated with these effects are unknown, interactions with the cholinergic system have been proposed. We examined the neurocognitive effects of short-term estradiol treatment and its interaction with the cholinergic system using the muscarinic receptor antagonist scopolamine in healthy young women. Thirty-four participants (Mean age+/-SD=22.4+/-4.4) completed baseline cognitive assessment and then received either 100 microg/day transdermal estradiol or transdermal placebo for 31 days. On days 28 and 31 of treatment, further cognitive assessment was performed pre- and 90 min post-scopolamine (0.4 mg) or placebo (saline) injection, under a randomized double-blind placebo-controlled design. Short-term estradiol treatment significantly enhanced spatial working memory with a trend for improvement in long-term verbal learning and memory. Overall, estradiol treatment did not protect against or attenuate the scopolamine-induced impairments in the cognitive domains assessed. Findings suggest that estrogen has minimal effects on cholinergic-mediated cognitive processes following short-term treatment. Effects of estradiol treatment may be dependent on age, dose of estradiol, integrity of cholinergic innervation and baseline endogenous estrogen levels, which may in part explain the inconsistent findings in the literature.
Publisher: IEEE
Date: 24-11-2022
Publisher: Wiley
Date: 2008
DOI: 10.1002/HUP.904
Abstract: N-methyl-D-aspartate (NMDA) receptors play an important role in learning and memory. Targeting the glycine modulatory site of the NMDA receptor has been suggested as a therapeutic strategy to improve cognition, although findings have not been convincing. We used the Cognitive Drug Research computerised assessment system to examine the effects of high-dose glycine on a number of cognitive processes in healthy young subjects. The study was a randomised placebo controlled repeated measures design in which each subject received acute placebo or glycine (0.8 g/kg) orally, with treatment conditions separated by a 5-day washout period. No significant effects of glycine were found on measures of working memory, declarative memory, attention or perceptual processing. These findings, together with those of previous studies, cast doubt over the ability of acute high-dose glycine to improve cognitive function in healthy subjects and suggest that the optimum dose of glycine for improving cognition may vary between different populations, possibly due to differences in endogenous glycine levels and the functional status of NMDA receptors.
Publisher: Wiley
Date: 2005
DOI: 10.1111/J.1468-8986.2005.00264.X
Abstract: EOG correction is a class of techniques that account for ocular artifact in the electroencephalogram (EEG) by subtracting electrooculographic data from the EEG. The purpose of this study was to evaluate four of these correction techniques (Verleger, Gasser, & Mocks, 1982 [VGM] Gratton, Coles, & Donchin, 1983 [GCD] Semlitsch, Presslich, Schuster, & Anderer, 1986 [SPSA] Croft & Barry, 2000 [CB]). Blinks, vertical eye movements (VEM), and horizontal eye movements (HEM) from 26 subjects were corrected using these techniques, and eye movement event-related potentials computed to aid validation. HEMs were corrected better by CB, VGM/GCD then SPSA, VEMs by CB, VGM/GCD then SPSA, and blinks by CB, SPSA, GCD and then VGM, with the advantage of CB substantial for blinks (eta2>.72), VEMs (eta2>.60), and HEMs (eta2>.27). It is argued that the CB procedure adequately accounts for ocular artifact in the EEG. Reasons for the limitations of the other procedures are discussed.
Start Date: 07-2005
End Date: 12-2007
Amount: $102,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2015
End Date: 12-2018
Amount: $289,201.00
Funder: Australian Research Council
View Funded Activity