ORCID Profile
0000-0002-0598-4358
Current Organisations
Macquarie University
,
Simon Fraser University
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Psychology | Biological Psychology (Neuropsychology, Psychopharmacology, Physiological Psychology) | Developmental Psychology and Ageing | Chinese Languages | Biological Psychology (Neuropsychology, Psychopharmacology, | Cognitive Science | Learning, Memory, Cognition And Language | Other Psychology and Cognitive Sciences | Neurocognitive Patterns And Neural Networks | Linguistic Processes (Incl. Speech Production And Comprehension) | Linguistic Structures (Incl. Grammar, Phonology, Lexicon, Semantics) | Mental Health | Sensory Processes, Perception and Performance | Psychology and Cognitive Sciences not elsewhere classified
ANZSRC Socio-Economic Objective (SEO)
Behavioural and cognitive sciences | Expanding Knowledge in Psychology and Cognitive Sciences | Child health | Biological sciences | Hearing, Vision, Speech and Their Disorders | Scientific instrumentation |
Related Links
Publications
Measurement Of Neuromagnetic Brain Function In Pre-school Children With Custom Sized MEG
Publisher: MyJove Corporation
Date: 19-02-2010
DOI: 10.3791/1693
Mu rhythm modulation during observation of an object-directed grasp
Publisher: Elsevier BV
Date: 04-2004
MEG Studies on the Connectivity of Brain Networks in Children
Publisher: Springer International Publishing
Date: 2019
Lateralization of brain activation in fluent and non-fluent preschool children
Publisher: Frontiers Media SA
Date: 28-05-2014
Event-related fields evoked by vocal response inhibition
Publisher: Springer Science and Business Media LLC
Date: 28-01-2016
DOI: 10.1007/S00221-016-4555-2
Abstract: The current study examined event-related fields (ERFs) evoked by vocal response inhibition in a stimulus-selective stop-signal task. We compared inhibition-related ERFs across a younger and an older group of adults. Behavioural results revealed that stop-signal reaction times (RTs), go-RTs, ignore-stop RTs and failed stop RTs were longer in the older, relative to the younger group by 38, 123, 149 and 116 ms, respectively. The litude of the ERF M2 peak (approximately 200 ms after the stop signal) evoked on successful stop trials was larger compared to that evoked on both failed stop and ignore-stop trials. The M4 peak (approximately 450 ms after stop signal) was of larger litude in both successful and failed stops compared to ignore-stop trials. In the older group, the M2, M3 and M4 peaks were smaller in litude and peaked later in time (by 24, 50 and 76 ms, respectively). We demonstrate that vocal response inhibition-related ERFs exhibit a similar temporal evolution to those previously described for manual response inhibition: an early peak at 200 ms (i.e. M2) that differentiates successful from failed stopping, and a later peak (i.e. M4) that is consistent with a neural marker of response checking and error processing. Across groups, our data support a more general decline of stimulus processing speed with age.
Two routes to expertise in mental rotation
Publisher: Wiley
Date: 15-05-2013
DOI: 10.1111/COGS.12042
Abstract: The ability to imagine objects undergoing rotation (mental rotation) improves markedly with practice, but an explanation of this plasticity remains controversial. Some researchers propose that practice speeds up the rate of a general-purpose rotation algorithm. Others maintain that performance improvements arise through the adoption of a new cognitive strategy-repeated exposure leads to rapid retrieval from memory of the required response to familiar mental rotation stimuli. In two experiments we provide support for an integrated explanation of practice effects in mental rotation by combining behavioral and EEG measures in a way that provides more rigorous inference than is available from either measure alone. Before practice, participants displayed two well-established signatures of mental rotation: Both response time and EEG negativity increased linearly with rotation angle. After extensive practice with a small set of stimuli, both signatures of mental rotation had all but disappeared. In contrast, after the same amount of practice with a much larger set both signatures remained, even though performance improved markedly. Taken together, these results constitute a reversed association, which cannot arise from variation in a single cause, and so they provide compelling evidence for the existence of two routes to expertise in mental rotation. We also found novel evidence that practice with the large but not the small stimulus set increased the magnitude of an early visual evoked potential, suggesting increased rotation speed is enabled by improved efficiency in extracting three-dimensional information from two-dimensional stimuli.
Face processing in the brains of pre-school aged children measured with MEG
Publisher: Elsevier BV
Date: 02-2015
DOI: 10.1016/J.NEUROIMAGE.2014.11.029
Abstract: There are two competing theories concerning the development of face perception: a late maturation account and an early maturation account. Magnetoencephalography (MEG) neuroimaging holds promise for adjudicating between the two opposing accounts by providing objective neurophysiological measures of face processing, with sufficient temporal resolution to isolate face-specific brain responses from those associated with other sensory, cognitive and motor processes. The current study used a customized child MEG system to measure M100 and M170 brain responses in 15 children aged three to six years while they viewed faces, cars and their phase-scrambled counterparts. Compared to adults tested using the same stimuli in a conventional MEG system, children showed significantly larger and later M100 responses. Children's M170 responses, derived by subtracting the responses to phase-scrambled images from the corresponding images (faces or cars) were delayed in latency but otherwise resembled the adult M170. This component has not been obtained in previous studies of young children tested using conventional adult MEG systems. However children did show a markedly reduced M170 response to cars in comparison to adults. This may reflect children's lack of expertise with cars relative to faces. Taken together, these data are in accord with recent behavioural and neuroimaging data that support early maturation of the basic face processing functions.
Concurrent MEG-articulography for investigating neuromotor control of speech articulation
Publisher: Cold Spring Harbor Laboratory
Date: 07-02-2020
DOI: 10.1101/2020.02.05.934489
Abstract: Articulography and functional neuroimaging are two major tools for studying the neurobiology of speech production. Until now, however, it has generally not been possible to use both in the same experimental setup because of technical incompatibilities between the two methodologies. Here we describe results from a novel articulography system dubbed Magneto-articulography for the Assessment of Speech Kinematics (MASK), used for the first time to obtain kinematic profiles of oro-facial movements during speech together with concurrent magnetoencephalographic (MEG) measurements of neuromotor brain activity. MASK was used to characterise speech kinematics in a healthy adult, and the results were compared to measurements from the same participant with a conventional electromagnetic articulography (EMA) setup. We also characterised speech movement kinematics with MASK in a group of ten typically developing children, aged 8-12 years. Analyses targeted the gestural landmarks of the utterances /ida/, /ila/ and reiterated productions of ataka/. These results demonstrate that the MASK technique can be used to reliably characterise movement profiles and kinematic parameters that reflect development of speech motor control, together with MEG measurements of brain responses from speech sensorimotor cortex. This new capability sets the stage for cross-disciplinary efforts to understand the developmental neurobiology of human speech production.
Epidemiology of RBC transfusions in patients with severe acute kidney injury: Analysis from the randomized evaluation of normal versus augmented level study
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2016
Reduced activation of left orbitofrontal cortex precedes blocked vocalization
Publisher: Elsevier BV
Date: 12-2012
DOI: 10.1016/J.JFLUDIS.2012.05.001
Abstract: While stuttering is known to be characterized by anomalous brain activations during speech, very little data is available describing brain activations during stuttering. To our knowledge there are no reports describing brain activations that precede blocking. In this case report we present magnetoencephalographic data from a person who stutters who had significant instances of blocking whilst performing a vowel production task. This unique data set has allowed us to compare the brain activations leading up to a block with those leading up to successful production. Surprisingly, the results are very consistent with data comparing fluent production in stutterers to controls. We show here that preceding a block there is significantly less activation of the left orbitofrontal and inferiorfrontal cortices. Furthermore, there is significant extra activation in the right orbitofrontal and inferiorfrontal cortices, and the sensorimotor and auditory areas bilaterally. This data adds weight to the argument forwarded by Kell et al. (2009) that the best functional sign of optimal repair in stutterering is activation of the left BA 47/12 in the orbitofrontal cortex. At the end of this activity the reader will be able to (a) identify brain regions associated with blocked vocalization, (b) discuss the functions of the orbitofrontal and inferior frontal cortices in regard to speech production and (c) describe the usefulness and limitations of magnetoencephalography (MEG) in stuttering research.
Object-related brain potentials associated with the perceptual segregation of a dichotically embedded pitch
Publisher: Acoustical Society of America (ASA)
Date: 2005
DOI: 10.1121/1.1828499
Abstract: The cortical mechanisms of perceptual segregation of concurrent sound sources were examined, based on binaural detection of interaural timing differences. Auditory event-related potentials were measured from 11 healthy subjects. Binaural stimuli were created by introducing a dichotic delay of 500-ms duration to a narrow frequency region within a broadband noise, and resulted in a perception of a centrally located noise and a right-lateralized pitch (dichotic pitch). In separate listening conditions, subjects actively discriminated and responded to randomly interleaved binaural and control stimuli, or ignored random stimuli while watching silent cartoons. In a third listening condition subjects ignored stimuli presented in homogenous blocks. For all listening conditions, the dichotic pitch stimulus elicited an object-related negativity (ORN) at a latency of about 150–250 ms after stimulus onset. When subjects were required to actively respond to stimuli, the ORN was followed by a P400 wave with a latency of about 320–420 ms. These results support and extend a two-stage model of auditory scene analysis in which acoustic streams are automatically parsed into component sound sources based on source-relevant cues, followed by a controlled process involving identification and generation of a behavioral response.
Graded cue information in dichotic pitch
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2007
Brief report
Publisher: Springer Science and Business Media LLC
Date: 31-03-2013
DOI: 10.1007/S10803-013-1805-Z
Abstract: Atypical auditory perception is a widely recognised but poorly understood feature of autism. In the current study, we used magnetoencephalography to measure the brain responses of 10 autistic children as they listened passively to dichotic pitch stimuli, in which an illusory tone is generated by sub-millisecond inter-aural timing differences in white noise. Relative to control stimuli that contain no inter-aural timing differences, dichotic pitch stimuli typically elicit an object related negativity (ORN) response, associated with the perceptual segregation of the tone and the carrier noise into distinct auditory objects. Autistic children failed to demonstrate an ORN, suggesting a failure of segregation however, comparison with the ORNs of age-matched typically developing controls narrowly failed to attain significance. More striking, the autistic children demonstrated a significant differential response to the pitch stimulus, peaking at around 50 ms. This was not present in the control group, nor has it been found in other groups tested using similar stimuli. This response may be a neural signature of atypical processing of pitch in at least some autistic in iduals.
Differential cortical processing of location and pitch changes in dichotic pitch
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 20-03-2006
Topographic distribution of the 40 Hz auditory evoked-Related potential in normal and aged subjects
Publisher: Springer Science and Business Media LLC
Date: 1988
DOI: 10.1007/BF01129176
Abstract: The establishment of the intestinal microbiota in newborns is a critical period with possible long-term consequences for human health. In this research, the development of the fecal microbiota of a group of exclusively breastfed neonates living in low socio-economic conditions in the city of São Paulo, Brazil, during the first month of life, was studied. Fecal s les were collected from ten neonates on the second, seventh, and 30(th) days after birth. One of the neonates underwent antibiotic therapy. Molecular techniques were used for analysis DNA was extracted from the s les, and 16S rRNA libraries were sequenced and phylogenetically analyzed after construction. A real-time polymerase chain reaction (PCR) was performed on the s les taken from the 30(th) day to lify DNA from Bifidobacterium sp. The primary phylogenetic groups identified in the s les were Escherichia and Clostridium. Staphylococcus was identified at a low rate. Bifidobacterium sp. was detected in all of the s les collected on the 30(th) day. In the child who received antibiotics, a reduction in anaerobes and Escherichia, which was associated with an overgrowth of Klebsiella, was observed throughout the experimental period. The observed pattern of Escherichia predominance and reduced Staphylococcus colonization is in contrast with the patterns observed in neonates living in developed countries.
Atypical brain responses to auditory spatial cues in adults with autism spectrum disorder
Publisher: Wiley
Date: 04-10-2018
DOI: 10.1111/EJN.13694
Abstract: The auditory processing atypicalities experienced by many in iduals on the autism spectrum disorder might be understood in terms of difficulties parsing the sound energy arriving at the ears into discrete auditory 'objects'. Here, we asked whether autistic adults are able to make use of two important spatial cues to auditory object formation - the relative timing and litude of sound energy at the left and right ears. Using electroencephalography, we measured the brain responses of 15 autistic adults and 15 age- and verbal-IQ-matched control participants as they listened to dichotic pitch stimuli - white noise stimuli in which interaural timing or litude differences applied to a narrow frequency band of noise typically lead to the perception of a pitch sound that is spatially segregated from the noise. Responses were contrasted with those to stimuli in which timing and litude cues were removed. Consistent with our previous studies, autistic adults failed to show a significant object-related negativity (ORN) for timing-based pitch, although their ORN was not significantly smaller than that of the control group. Autistic participants did show an ORN to litude cues, indicating that they do not experience a general impairment in auditory object formation. However, their P400 response - thought to indicate the later attention-dependent aspects of auditory object formation - was missing. These findings provide further evidence of atypical auditory object processing in autism with potential implications for understanding the perceptual and communication difficulties associated with the condition.
Beta oscillations, timing, and stuttering
Publisher: Frontiers Media SA
Date: 05-01-2015
Event-related potentials for interaural time differences and spectral cues
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2009
Erythropoiesis-stimulating Agents in Critically Ill Trauma Patients
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2017
Behavioral and multimodal neuroimaging evidence for a deficit in brain timing networks in stuttering: a hypothesis and theory
Publisher: Frontiers Media SA
Date: 25-06-2014
Self-initiation and temporal cueing of monaural tones reduce the auditory N1 and P2
Publisher: Springer Science and Business Media LLC
Date: 11-08-2012
DOI: 10.1007/S00221-012-3204-7
Abstract: Event-related potentials (ERPs) to tones that are self-initiated are reduced in their magnitude in comparison with ERPs to tones that are externally generated. This phenomenon has been taken as evidence for an efference copy of the motor command acting to suppress the sensory response. However, self-initiation provides a strong temporal cue for the stimulus which might also contribute to the ERP suppression for self-initiated tones. The current experiment sought to investigate the suppression of monaural tones by temporal cueing and also whether the addition of self-initiation enhanced this suppression. Lastly, the experiment sought to investigate the lateralisation of the ERP suppression via presenting these monaural tones to each ear respectively. We examined source waveforms extracted from the lateralised auditory cortices and measured the modulation of the N1 and P2 components by cueing and self-initiation. Self-initiation significantly reduced the litude of the N1 component. Temporal cueing without self-initiation significantly reduced the P2 component. There were no significant differences in the litude of either the N1 or the P2 between self-initiation and temporal cuing. There was a significant lateralisation effect on the N1—it being significantly larger contralateral to the ear of stimulation. There was no interaction between lateralisation and side of the temporal cue or side of self-initiation suggesting that the effects of self-initiation and temporal cuing are equal bilaterally. We conclude that a significant proportion of ERP suppression by self-initiation is a result of inherent temporal cueing.
Non-invasive investigation of human hippocampal rhythms using magnetoencephalography
Publisher: Frontiers Media SA
Date: 26-04-2018
Comparison of the N300 and N400 ERPs to picture stimuli in congruent and incongruent contexts
Publisher: Elsevier BV
Date: 08-2002
DOI: 10.1016/S1388-2457(02)00161-X
Abstract: The aim of this study was to examine the N300 and N400 effect to pictures that were semantically incongruous to a prior object name. Based upon theories of object identification, the semantic incongruity was manipulated to occur early or late in the object processing stream. High-density visual event-related potentials were measured in response to passively viewed black and white line drawings of common objects. Pictures were preceded with an object name at either the basic (categorical) or subordinate (specific) level. The object either matched or mismatched with the name. With subordinate level names, mismatches could be within- or between-category. The N400 effect was found for both basic and subordinate level mismatches. The N400 was found for both the subordinate-within and subordinate-between. Comparison of the scalp distributions between these N400 effects suggested a common effect was found for all conditions. The N300 effect, however, was only found for between-category mismatches, and only when semantic expectations were high in the match baseline (subordinate matches). The findings are consistent with theories of object identification that suggest that objects are initially categorized prior to being identified at more specific levels. The N300 appears to reflect the categorisation while the N400 effect appears to be responsive to all semantic mismatches. Comparison of scalp topographies, functional differences, and different estimated cortical source locations suggest that the N300 and N400 are two distinct semantic effects that reflect aspects of object identification.
One good turn deserves another
Publisher: Elsevier BV
Date: 2004
Grey matter volume differences in the left caudate nucleus of people who stutter
Publisher: Elsevier BV
Date: 2017
DOI: 10.1016/J.BANDL.2016.08.009
Abstract: The cause of stuttering has many theoretical explanations. A number of research groups have suggested changes in the volume and/or function of the striatum as a causal agent. Two recent studies in children and one in adults who stutter (AWS) report differences in striatal volume compared that seen in controls however, the laterality and nature of this anatomical volume difference is not consistent across studies. The current study investigated whether a reduction in striatal grey matter volume, comparable to that seen in children who stutter (CWS), would be found in AWS. Such a finding would support claims that an anatomical striatal anomaly plays a causal role in stuttering. We used voxel-based morphometry to examine the structure of the striatum in a group of AWS and compared it to that in a group of matched adult control subjects. Results showed a statistically significant group difference for the left caudate nucleus, with smaller mean volume in the group of AWS. The caudate nucleus, one of three main structures within the striatum, is thought to be critical for the planning and modulation of movement sequencing. The difference in striatal volume found here aligns with theoretical accounts of stuttering, which suggest it is a motor control disorder that arises from deficient articulatory movement selection and sequencing. Whilst the current study provides further evidence of a striatal volume difference in stuttering at the group level compared to controls, the significant overlap between AWS and controls suggests this difference is unlikely to be diagnostic of stuttering.
Liberal Versus Conventional Glucose Targets in Critically Ill Diabetic Patients: An Exploratory Safety Cohort Assessment
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2016
DOI: 10.1097/CCM.0000000000001742
Abstract: To assess the feasibility, safety, and impact on relative hypoglycemia of liberal versus conventional blood glucose concentration targets in critically ill diabetic patients. Prospective, open-label, sequential-period exploratory study. A 22-bed multidisciplinary ICU of a tertiary care hospital in Australia. Eighty adult diabetic patients, 40 from the conventional before period and 40 from the liberal after period. Blood glucose concentration targets were 6–10 mmol/L during the before period and 10–14 mmol/L during the after period. We used admission glycated hemoglobin to estimate premorbid baseline blood glucose concentration. We defined glycemic distance as the difference between blood glucose concentration in ICU and baseline blood glucose concentration. During the first 48 ICU hours, we recorded absolute (blood glucose concentration, 3.9 mmol/L) and relative (glycemic distance, 30% below baseline) hypoglycemia rates, insulin administration, and outcomes. The groups had similar baseline characteristics. We observed a negative glycemic distance in 248 of 488 blood glucose concentrations (50.8%) during the before period and 164 of 485 (33.8%) during the after period ( p 0.001). We detected relative hypoglycemia in 20 (50.0%) and nine (22.5%) patients in the before and after periods, respectively ( p = 0.01). On day 1, 50.0% and 16.7% received insulin in the before and after periods ( p = 0.007). ICU and hospital length of stay and mortality were similar between groups. In a safety cohort of critically ill diabetic patients, a blood glucose concentration target of 10–14 mmol/L resulted in fewer episodes of negative glycemic distance or relative hypoglycemia and reduced insulin administration compared with a target of 6–10 mmol/L.
CenEEGs
Publisher: Association for Computing Machinery (ACM)
Date: 18-02-2020
DOI: 10.1145/3371153
Abstract: This article explores valid brain electroencephalography (EEG) selection for EEG classification with different classifiers, which has been rarely addressed in previous studies and is mostly ignored by existing EEG processing methods and applications. Importantly, traditional selection methods are not able to select valid EEG signals for different classifiers. This article focuses on a source control-based valid EEG selection to reduce the impact of invalid EEG signals and aims to improve EEG-based classification performance for different classifiers. We propose a novel centroid-based EEG selection approach named CenEEGs, which uses a scale-and-shift-invariance similarity metric to measure similarities of EEG signals and then applies a globally optimal centroid strategy to select valid EEG signals with respect to a similarity threshold. A detailed comparison with several state-of-the-art time series selection methods by using standard criteria on 8 EEG datasets demonstrates the efficacy and superiority of CenEEGs for different classifiers.
A high density ERP comparison of mental rotation and mental size transformation
Publisher: Elsevier BV
Date: 07-2003
DOI: 10.1016/S0278-2626(03)00077-0
Abstract: To compare mental rotation and mental size transformation, 128-channel EEG was recorded while subjects performed both tasks using random two-dimensional shapes as stimuli. Behavioural results showed significant linear effects of both size transformation and mental rotation on reaction times. Rotation ERPs showed experimental effects at two latencies: a bilateral component distributed over posterior parietal electrodes at a latency of approximately 232-300ms and a second component at approximately 424-492ms distributed over right anterior parietal electrodes. The latency and spatial distribution of this second effect is consistent with previous research indicating a functional connection between this component and mental rotation. ERPs for the size-transformation task showed an effect at 180-228ms distributed bilaterally over occipital-temporal electrodes. These results are consistent with previous hemodynamic imaging studies that show involvement of parietal cortex in mental rotation and also the involvement of BA 19 in size-transformation tasks. However, the superior temporal resolution of the present data indicates that BA 19 activation may occur at a latency that is more likely related to apparent motion than to the size-transformation operation per se.
A Dual Mechanism Neural Framework for Social Understanding
Publisher: Informa UK Limited
Date: 02-2007
Neural processing of observed oro-facial movements reflects multiple action encoding strategies in the human brain
Publisher: Elsevier BV
Date: 02-2006
DOI: 10.1016/J.BRAINRES.2005.11.053
Abstract: In this experiment, the oscillatory responses of the MEG were characterized during the observation of four viewing conditions: (a) observation of mouth movements, (b) observation of a non-biological motion stimulus (a mechanical aperture opening and shutting), (c) observation of object-directed mouth movements and (d) observation of speech-like mouth movements. Data were analyzed using synthetic aperture magnetometry (SAM) in three frequency bands, beta (15-35 Hz), gamma (35-70 Hz) and alpha/mu (8-15 Hz). Results showed that observations of biological motion resulted in beta desynchronization over lateral sensorimotor areas, while observations of non-biological motion resulted in a more medial desynchronization, an effect that may be related to the processing of a structured event sequence. Observation of linguistic movements resulted in less alpha/beta desynchronization in posterior brain regions in comparison to biological motion stimuli, suggesting that linguistically-relevant stimuli are processed with different neuronal systems than those recruited by normal action observation. We suggest that non-linguistic actions recruit dorsal systems while linguistic actions engage ventral processing systems. Object-directed movements showed the largest sensorimotor activations, suggesting that, as is the case for observations of hand movements, motoric processing is particularly sensitive to the viewing of goal-directed actions. Taken together, the results indicate that the brain utilizes multiple action encoding strategies, tailored to the function of the observed movement.
Primary motor cortex activation during action observation revealed by wavelet analysis of the EEG
Publisher: Elsevier BV
Date: 08-2004
An efficient and adaptive test of auditory mental imagery
Publisher: Springer Science and Business Media LLC
Date: 30-04-2020
DOI: 10.1007/S00426-020-01322-3
Abstract: The ability to silently hear music in the mind has been argued to be fundamental to musicality. Objective measurements of this subjective imagery experience are needed if this link between imagery ability and musicality is to be investigated. However, previous tests of musical imagery either rely on self-report, rely on melodic memory, or do not cater in range of abilities. The Pitch Imagery Arrow Task (PIAT) was designed to address these shortcomings however, it is impractically long. In this paper, we shorten the PIAT using adaptive testing and automatic item generation. We interrogate the cognitive processes underlying the PIAT through item response modelling. The result is an efficient online test of auditory mental imagery ability (adaptive Pitch Imagery Arrow Task: aPIAT) that takes 8 min to complete, is adaptive to participant’s in idual ability, and so can be used to test participants with a range of musical backgrounds. Performance on the aPIAT showed positive moderate-to-strong correlations with measures of non-musical and musical working memory, self-reported musical training, and general musical sophistication. Ability on the task was best predicted by the ability to maintain and manipulate tones in mental imagery, as well as to resist perceptual biases that can lead to incorrect responses. As such, the aPIAT is the ideal tool in which to investigate the relationship between pitch imagery ability and musicality.
Adaptive Motor Imagery
Publisher: Oxford University Press (OUP)
Date: 04-12-2016
Abstract: The consequences of losing the ability to move a limb are traumatic. One approach that examines the impact of pathological limb nonuse on the brain involves temporary immobilization of a healthy limb. Here, we investigated immobilization-induced plasticity in the motor imagery (MI) circuitry during hand immobilization. We assessed these changes with a multimodal paradigm, using functional magnetic resonance imaging (fMRI) to measure neural activation, magnetoencephalography (MEG) to track neuronal oscillatory dynamics, and transcranial magnetic stimulation (TMS) to assess corticospinal excitability. fMRI results show a significant decrease in neural activation for MI of the constrained hand, localized to sensorimotor areas contralateral to the immobilized hand. MEG results show a significant decrease in beta desynchronization and faster resynchronization in sensorimotor areas contralateral to the immobilized hand. TMS results show a significant increase in resting motor threshold in motor cortex contralateral to the constrained hand, suggesting a decrease in corticospinal excitability in the projections to the constrained hand. These results demonstrate a direct and rapid effect of immobilization on MI processes of the constrained hand, suggesting that limb nonuse may not only affect motor execution, as evidenced by previous studies, but also MI. These findings have important implications for the effectiveness of therapeutic approaches that use MI as a rehabilitation tool to ameliorate the negative effects of limb nonuse.
Neuromagnetic brain activity associated with anticipatory postural adjustments for bimanual load lifting
Publisher: Elsevier BV
Date: 02-2013
DOI: 10.1016/J.NEUROIMAGE.2012.10.042
Abstract: During bimanual load lifting, the brain must anticipate the effects of unloading upon the load-bearing arm. Little is currently known about the neural networks that coordinate these anticipatory postural adjustments. We measured neuromagnetic brain activity with whole-head magnetoencephalography while participants performed a bimanual load-lifting task. Anticipatory adjustments were associated with reduction in biceps brachii muscle activity of the load-bearing arm and pre-movement desynchronization of the cortical beta rhythm. Beamforming analyses localized anticipatory brain activity to the precentral gyrus, basal ganglia, supplementary motor area, and thalamus, contralateral to the load-bearing arm. To our knowledge this is the first human neuroimaging study to directly investigate anticipatory postural adjustments and to explicitly partition the anticipatory and volitional aspects of brain activity in bimanual load lifting. These data contribute to our understanding of the neural systems supporting anticipatory postural adjustments in healthy adults.
Premovement brain activity in a bimanual load-lifting task
Publisher: Springer Science and Business Media LLC
Date: 13-11-2010
DOI: 10.1007/S00221-010-2470-5
Abstract: Even the simplest volitional movements must be precisely coordinated with anticipatory postural adjustments. Little is currently known about the neural networks that coordinate these adjustments in healthy adults. We measured brain activity prior to movement during a bimanual load-lifting task, designed to elicit anticipatory adjustments in a restricted and well-defined set of musculature in the arm. Electroencephalography and magnetoencephalography brain measurements were obtained from eleven participants while they performed a bimanual load-lifting task that required precise inter-limb coordination. Anticipatory biceps brachii inhibition in the loaded arm was associated with a robust desynchronization of the beta rhythm. Beamforming analyses localized beta band responses to the parietal lobules, pre- and post-central gyri, middle and medial frontal gyri, basal ganglia and thalamus. The current study shows that premovement brain activity in a bimanual load-lifting task can be imaged with magnetoencephalography. Future experiments will partition out brain activity associated with anticipatory postural adjustments and volitional movements. The experimental paradigm will also be useful in the study of motor function in patients with developmental or degenerative disorders.
Lateralized auditory brain function in children with normal reading ability and in children withdyslexia
Publisher: Elsevier BV
Date: 03-2013
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2012.12.015
Abstract: We examined central auditory processing in typically- and atypically-developing readers. Concurrent EEG and MEG brain measurements were obtained from a group of 16 children with dyslexia aged 8-12 years, and a group of 16 age-matched children with normal reading ability. Auditory responses were elicited using 500ms duration broadband noise. These responses were strongly lateralized in control children. Children with dyslexia showed significantly less lateralisation of auditory cortical functioning, and a different pattern of development of auditory lateralization with age. These results provide further evidence that the core neurophysiological deficit of dyslexia is a problem in the balance of auditory function between the two hemispheres.
Cerebral processes during visuo-motor imagery of hands
Publisher: Wiley
Date: 23-06-2006
DOI: 10.1111/J.1469-8986.2006.00404.X
Abstract: We investigated the role of cerebral motor structures during mental hand rotation. Neural activity was measured with event-related potentials (ERPs) in 16 healthy participants while they performed handedness judgments of visually presented hands. Mental rotation was associated with ERP litude modulations as early as 170 ms but most strongly during a time window of about 600-800 ms. Source analysis of ERPs during these time windows indicated generators in bilateral extrastriate and parietal cortices. The results do not support a direct involvement of anterior motor cortices in the neural computations underlying mental rotation. However, motor regions may play a role in providing ongoing kinaesthetic feedback during mental rotation or in checking the results of the imagined transformation.
A multicenter study on the effect of continuous hemodiafiltration intensity on antibiotic pharmacokinetics
Publisher: Springer Science and Business Media LLC
Date: 12-2015
DOI: 10.1186/S13054-015-0818-8
Abstract: Continuous renal replacement therapy (CRRT) may alter antibiotic pharmacokinetics and increase the risk of incorrect dosing. In a nested cohort within a large randomized controlled trial, we assessed the effect of higher (40 mL/kg per hour) and lower (25 mL/kg per hour) intensity CRRT on antibiotic pharmacokinetics. We collected serial blood s les to measure ciprofloxacin, meropenem, piperacillin-tazobactam, and vancomycin levels. We calculated extracorporeal clearance (CL), systemic CL, and volume of distribution (Vd) by non-linear mixed-effects modelling. We assessed the influence of CRRT intensity and other patient factors on antibiotic pharmacokinetics. We studied 24 patients who provided 179 pairs of s les. Extracorporeal CL increased with higher-intensity CRRT but the increase was significant for vancomycin only (mean 28 versus 22 mL/minute P = 0.0003). At any given prescribed CRRT effluent rate, extracorporeal CL of in idual antibiotics varied widely, and the effluent-to-plasma concentration ratio decreased with increasing effluent flow. Overall, systemic CL varied to a greater extent than Vd, particularly for meropenem, piperacillin, and tazobactam, and large intra-in idual differences were also observed. CRRT dose did not influence overall (systemic) CL, Vd, or half-life. The proportion of systemic CL due to CRRT varied widely and was high in some cases. In patients receiving CRRT, there is great variability in antibiotic pharmacokinetics, which complicates an empiric approach to dosing and suggests the need for therapeutic drug monitoring. More research is required to investigate the apparent relative decrease in clearance at higher CRRT effluent rates. ClinicalTrials.gov NCT00221013 . Registered 14 September 2005.
Prognostic Accuracy of the SOFA Score, SIRS Criteria, and qSOFA Score for In-Hospital Mortality Among Adults With Suspected Infection Admitted to the Intensive Care Unit
Publisher: American Medical Association (AMA)
Date: 17-01-2017
Abstract: The Sepsis-3 Criteria emphasized the value of a change of 2 or more points in the Sequential [Sepsis-related] Organ Failure Assessment (SOFA) score, introduced quick SOFA (qSOFA), and removed the systemic inflammatory response syndrome (SIRS) criteria from the sepsis definition. Externally validate and assess the discriminatory capacities of an increase in SOFA score by 2 or more points, 2 or more SIRS criteria, or a qSOFA score of 2 or more points for outcomes among patients who are critically ill with suspected infection. Retrospective cohort analysis of 184 875 patients with an infection-related primary admission diagnosis in 182 Australian and New Zealand intensive care units (ICUs) from 2000 through 2015. SOFA, qSOFA, and SIRS criteria applied to data collected within 24 hours of ICU admission. The primary outcome was in-hospital mortality. In-hospital mortality or ICU length of stay (LOS) of 3 days or more was a composite secondary outcome. Discrimination was assessed using the area under the receiver operating characteristic curve (AUROC). Adjusted analyses were performed using a model of baseline risk determined using variables independent of the scoring systems. Among 184 875 patients (mean age, 62.9 years [SD, 17.4] women, 82 540 [44.6%] most common diagnosis bacterial pneumonia, 32 634 [17.7%]), a total of 34 578 patients (18.7%) died in the hospital, and 102 976 patients (55.7%) died or experienced an ICU LOS of 3 days or more. SOFA score increased by 2 or more points in 90.1% 86.7% manifested 2 or more SIRS criteria, and 54.4% had a qSOFA score of 2 or more points. SOFA demonstrated significantly greater discrimination for in-hospital mortality (crude AUROC, 0.753 [99% CI, 0.750-0.757]) than SIRS criteria (crude AUROC, 0.589 [99% CI, 0.585-0.593]) or qSOFA (crude AUROC, 0.607 [99% CI, 0.603-0.611]). Incremental improvements were 0.164 (99% CI, 0.159-0.169) for SOFA vs SIRS criteria and 0.146 (99% CI, 0.142-0.151) for SOFA vs qSOFA (P <.001). SOFA (AUROC, 0.736 [99% CI, 0.733-0.739]) outperformed the other scores for the secondary end point (SIRS criteria: AUROC, 0.609 [99% CI, 0.606-0.612] qSOFA: AUROC, 0.606 [99% CI, 0.602-0.609]). Incremental improvements were 0.127 (99% CI, 0.123-0.131) for SOFA vs SIRS criteria and 0.131 (99% CI, 0.127-0.134) for SOFA vs qSOFA (P <.001). Findings were consistent for both outcomes in multiple sensitivity analyses. Among adults with suspected infection admitted to an ICU, an increase in SOFA score of 2 or more had greater prognostic accuracy for in-hospital mortality than SIRS criteria or the qSOFA score. These findings suggest that SIRS criteria and qSOFA may have limited utility for predicting mortality in an ICU setting.
ERP measures of material specificity for cross-modal relational memory
Publisher: Elsevier BV
Date: 07-2009
Defining the characteristics and expectations of fluid bolus therapy: A worldwide perspective
Publisher: Elsevier BV
Date: 10-2016
DOI: 10.1016/J.JCRC.2016.05.017
Abstract: The purpose of the study is to understand what clinicians believe defines fluid bolus therapy (FBT) and the expected response to such intervention. We asked intensive care specialists in 30 countries to participate in an electronic questionnaire of their practice, definition, and expectations of FBT. We obtained 3138 responses. Despite much variation, more than 80% of respondents felt that more than 250 mL of either colloid or crystalloid fluid given over less than 30 minutes defined FBT, with crystalloids most acceptable. The most acceptable crystalloid and colloid for use as FBT were 0.9% saline and 4% albumin solution, respectively. Most respondents believed that one or more of the following physiological changes indicates a response to FBT: a mean arterial pressure increase greater than 10 mm Hg, a heart rate decrease greater than 10 beats per minute, an increase in urinary output by more than 10 mL/h, an increase in central venous oxygen saturation greater than 4%, or a lactate decrease greater than 1 mmol/L. Despite wide variability between in iduals and countries, clear majority views emerged to describe practice, define FBT, and identify a response to it. Further investigation is now required to describe actual FBT practice and to identify the magnitude and duration of the physiological response to FBT and its relationship to patient-centered outcomes.
Individual differences in motor development during early childhood: An MEG study
Publisher: Wiley
Date: 09-01-2020
DOI: 10.1111/DESC.12935
Abstract: In a previous study, we reported the first measurements of pre-movement and sensorimotor cortex activity in preschool age children (ages 3-5 years) using a customized pediatric magnetoencephalographic system. Movement-related activity in the sensorimotor cortex differed from that typically observed in adults, suggesting that maturation of cortical motor networks was still incomplete by late preschool age. Here we compare these earlier results to a group of school age children (ages 6-8 years) including seven children from the original study measured again two years later, and a group of adults (mean age 31.1 years) performing the same task. Differences in movement-related brain activity were observed both longitudinally within children in which repeated measurements were made, and cross-sectionally between preschool age children, school age children, and adults. Movement-related mu (8-12 Hz) and beta (15-30 Hz) oscillations demonstrated linear increases in litude and mean frequency with age. In contrast, movement-evoked gamma synchronization demonstrated a step-like transition from low (30-50 Hz) to high (70-90 Hz) narrow-band oscillations, and this occurred at different ages in different children. Notably, pre-movement activity ('readiness fields') observed in adults was absent in even the oldest children. These are the first direct observations of brain activity accompanying motor responses throughout early childhood, confirming that maturation of this activity is still incomplete by mid-childhood. In addition, in idual children demonstrated markedly different developmental trajectories in movement-related brain activity, suggesting that in idual differences need to be taken into account when studying motor development across age groups.
Reduced object related negativity response indicates impaired auditory scene analysis in adults with autistic spectrum disorder
Publisher: PeerJ
Date: 25-02-2014
DOI: 10.7717/PEERJ.261
Intensive care nurses' self-reported practice of intravenous fluid bolus therapy
Publisher: Elsevier BV
Date: 12-2015
Studying Brain Function in Children Using Magnetoencephalography
Publisher: MyJove Corporation
Date: 08-02-2019
DOI: 10.3791/58909
Abstract: Magnetoencephalography (MEG) is a non-invasive neuroimaging technique which directly measures magnetic fields produced by the electrical activity of the human brain. MEG is quiet and less likely to induce claustrophobia compared with magnetic resonance imaging (MRI). It is therefore a promising tool for investigating brain function in young children. However, analysis of MEG data from pediatric populations is often complicated by head movement artefacts which arise as a consequence of the requirement for a spatially-fixed sensor array that is not affixed to the child's head. Minimizing head movements during MEG sessions can be particularly challenging as young children are often unable to remain still during experimental tasks. The protocol presented here aims to reduce head movement artefacts during pediatric MEG scanning. Prior to visiting the MEG laboratory, families are provided with resources that explain the MEG system and the experimental procedures in simple, accessible language. An MEG familiarization session is conducted during which children are acquainted with both the researchers and the MEG procedures. They are then trained to keep their head still whilst lying inside an MEG simulator. To help children feel at ease in the novel MEG environment, all of the procedures are explained through the narrative of a space mission. To minimize head movement due to restlessness, children are trained and assessed using fun and engaging experimental paradigms. In addition, children's residual head movement artefacts are compensated for during the data acquisition session using a real-time head movement tracking system. Implementing these child-friendly procedures is important for improving data quality, minimizing participant attrition rates in longitudinal studies, and ensuring that families have a positive research experience.
Turn that frown upside down
Publisher: Wiley
Date: 11-09-2003
Abstract: When inverted, thatcherized faces appear normal. This may be due to a decrease in configural and an increase in featural processing. It is not known whether this processing is continuous or reflects two distinct processing systems. Using event-related potentials (ERPs), we investigated the Thatcher effect on thatcherized and normal faces at varying orientations. The ERPs paralleled the perceptual illusion. The effect of thatcherization on upright faces was visible in P1 and N170 ERP components, possibly reflecting attentional engagement due to unpleasantness of thatcherized faces. Effects were also found over two later components, the P250 component, which has been related to configural recognition, and a late parietal component possibly reflecting featural processing. The effect of thatcherization on the two later components decreased gradually (for the P250 component) and abruptly (for the late parietal component) as the faces were rotated away from the upright.
Processing of binaural Information in human auditory cortex
Publisher: InTech
Date: 11-04-2011
DOI: 10.5772/597
Poorer speech reception threshold in noise is associated with lower brain volume in auditory and cognitive processing regions
Publisher: American Speech Language Hearing Association
Date: 26-04-2019
DOI: 10.1044/2018_JSLHR-H-ASCC7-18-0142
Abstract: Hearing loss is associated with changes in brain volume in regions supporting auditory and cognitive processing. The purpose of this study was to determine whether there is a systematic association between hearing ability and brain volume in cross-sectional data from a large nonclinical cohort of middle-aged adults available from the UK Biobank Resource ( www.ukbiobank.ac.uk ). We performed a set of regression analyses to determine the association between speech reception threshold in noise (SRTn) and global brain volume as well as predefined regions of interest (ROIs) based on T1-weighted structural images, controlling for hearing-related comorbidities and cognition as well as demographic factors. In a 2nd set of analyses, we additionally controlled for hearing aid (HA) use. We predicted statistically significant associations globally and in ROIs including auditory and cognitive processing regions, possibly modulated by HA use. Whole-brain gray matter volume was significantly lower for in iduals with poorer SRTn. Furthermore, the volume of 9 predicted ROIs including both auditory and cognitive processing regions was lower for in iduals with poorer SRTn. The greatest percentage difference (−0.57%) in ROI volume relating to a 1 SD worsening of SRTn was found in the left superior temporal gyrus. HA use did not substantially modulate the pattern of association between brain volume and SRTn. In a large middle-aged nonclinical population, poorer hearing ability is associated with lower brain volume globally as well as in cortical and subcortical regions involved in auditory and cognitive processing, but there was no conclusive evidence that this effect is moderated by HA use. This pattern of results supports the notion that poor hearing leads to reduced volume in brain regions recruited during speech understanding under challenging conditions. These findings should be tested in future longitudinal, experimental studies. 0.23641/asha.7949357
Cortical beta oscillations and motor thresholds differ across the spectrum of post-stroke motor impairment, a preliminary MEG and TMS study
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.BRAINRES.2015.09.037
Abstract: Cortical oscillatory activity in the beta frequency band (13-30Hz) is associated with voluntary movement and may be altered in motor disorders such as stroke. We used a multimodal case-series approach to investigate movement-related beta oscillations, cortical excitability and upper-limb motor-function in 10 chronic stroke-patients across a broad range of motor-impairment. Assessments included: (i) whole-head magnetoencephalography (MEG) during a voluntary motor task (ii) resting and active motor-thresholds to transcranial magnetic stimulation (TMS) and (iii) assessments of upper-limb motor-function. MEG revealed distinct patterns of movement-related beta oscillations according to motor-function. An elongated event-related desynchronisation (ERD) was correlated with poorer motor-function (p=0.004) whereas an elongated event-related resynchronisation (ERS) was correlated with higher motor function and lower TMS motor thresholds on the more-affected side (p=0.014 and p<0.001, respectively). Oscillation litude and laterality were also correlated with motor-function, where a stronger ERD/ERS and a greater relative contribution from the ipsilesional hemisphere were correlated with better motor-function (p=0.016, p=0.025). Unlike TMS responses and motor-function, the temporal profile of beta oscillations was largely symmetrical for movements of the more- and less-affected hands. Beta ERD/ERS patterns differ across the post-stroke motor impairment spectrum, and are bilaterally similar after stroke. Both the litude and duration of beta oscillations relate to post-stroke motor-function. The contralesional hemisphere is not unaffected post-stroke. Caution is needed when generalising imaging and neurophysiological findings from patients with moderate to high motor ability to the more heterogeneous general stroke population and particularly those with low levels of residual voluntary motor-function.
Changes in rolandic mu rhythm during observation of a precision grip
Publisher: Wiley
Date: 07-11-2003
Long‐term potentiation of human visual evoked responses
Publisher: Wiley
Date: 04-2005
A Pilot Assessment of Carotid and Brachial Artery Blood Flow Estimation Using Ultrasound Doppler in Cardiac Surgery Patients
Publisher: Elsevier BV
Date: 2016
The Pitch Imagery Arrow Task
Publisher: Public Library of Science (PLoS)
Date: 25-03-2015
Deconvolution of magnetic acoustic change complex (mACC)
Publisher: Elsevier BV
Date: 11-2014
DOI: 10.1016/J.CLINPH.2014.03.003
Abstract: The aim of this study was to design a novel experimental approach to investigate the morphological characteristics of auditory cortical responses elicited by rapidly changing synthesized speech sounds. Six sound-evoked magnetoencephalographic (MEG) responses were measured to a synthesized train of speech sounds using the vowels /e/ and /u/ in 17 normal hearing young adults. Responses were measured to: (i) the onset of the speech train, (ii) an F0 increment (iii) an F0 decrement (iv) an F2 decrement (v) an F2 increment and (vi) the offset of the speech train using short (jittered around 135ms) and long (1500ms) stimulus onset asynchronies (SOAs). The least squares (LS) deconvolution technique was used to disentangle the overlapping MEG responses in the short SOA condition only. Comparison between the morphology of the recovered cortical responses in the short and long SOAs conditions showed high similarity, suggesting that the LS deconvolution technique was successful in disentangling the MEG waveforms. Waveform latencies and litudes were different for the two SOAs conditions and were influenced by the spectro-temporal properties of the sound sequence. The magnetic acoustic change complex (mACC) for the short SOA condition showed significantly lower litudes and shorter latencies compared to the long SOA condition. The F0 transition showed a larger reduction in litude from long to short SOA compared to the F2 transition. Lateralization of the cortical responses were observed under some stimulus conditions and appeared to be associated with the spectro-temporal properties of the acoustic stimulus. The LS deconvolution technique provides a new tool to study the properties of the auditory cortical response to rapidly changing sound stimuli. The presence of the cortical auditory evoked responses for rapid transition of synthesized speech stimuli suggests that the temporal code is preserved at the level of the auditory cortex. Further, the reduced litudes and shorter latencies might reflect intrinsic properties of the cortical neurons to rapidly presented sounds. This is the first demonstration of the separation of overlapping cortical responses to rapidly changing speech sounds and offers a potential new biomarker of discrimination of rapid transition of sound.
Functional imaging of Brain responses to repetitive sensory stimulation
Publisher: Springer Science and Business Media LLC
Date: 1989
DOI: 10.1007/BF01128854
Poster Session Abstracts
Publisher: Wiley
Date: 20-08-2012
Face-sensitive brain responses measured from a four-year-old child with a custom-sized child MEG system
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.JNEUMETH.2013.11.020
Abstract: Previous magnetoencephalography (MEG) studies have failed to find a facesensitive, brain response-M170 in children. If this is the case, this suggests that the developmental trajectory of the M170 is different from that of its electrical equivalent, the N170. We investigated the alternative possibility that the child M170 may not be detectable in conventional adult-sized MEG systems. Brain responses to pictures of faces and well controlled stimuli were measured from the same four-year-old child with a custom child MEG system and an adult-sized MEG system. The goodness of fit of the child's head was about the same over the occipital head surface in both systems, but was much worse over all other parts of the head surface in the adult MEG system compared to the child MEG system. The face-sensitive M170 was measured from the child in both MEG systems, but was larger in litude, clearer in morphology, and had a more accurate source localization when measured in the child MEG system. The custom-sized child MEG system is superior for measuring the face-sensitive M170 brain response in children than the conventional adult MEG system. The present results show that the face-sensitive M170 brain response can be elicited in a four-year-old child. This provides new evidence for early maturation of face processing brain mechanisms in humans, and offers new opportunities for the study of neurodevelopmental disorders that show atypical face processing capabilities, such as autism spectrum disorder.
Processing of binaural spatial information in human auditory cortex
Publisher: Elsevier BV
Date: 07-2010
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2010.05.008
Abstract: This study was designed to test two hypotheses about binaural hearing: (1) that binaural cues are primarily processed in the hemisphere contralateral to the perceived location of a sound and (2) that the two main binaural cues, interaural timing differences and interaural level differences, are processed in separate channels in the auditory cortex. Magnetoencephalography was used to measure brain responses to dichotic pitches--a perception of pitch created by segregating a narrow band of noise from a wider band of noise--derived from interaural timing or level disparities. Our results show a strong modulation of interhemispheric M100 litudes by ITD cues. When these cues simulated source presentation unilaterally from the right hemispace, M100 litude changed from a predominant right hemisphere pattern to a bilateral pattern. In contrast, ILD cues lacked any capacity to alter the right hemispheric distribution. These data indicate that intrinsic hemispheric biases are large in comparison to any contralaterality biases in the auditory system. Importantly, both types of binaural cue elicited a circa 200 ms latency object-related negativity component, believed to reflect automatic cortical processes involved in distinguishing concurrent auditory objects. These results support the conclusion that ITDs and ILDs are processed by distinct neuronal populations to relatively late stages of cortical processing indexed by the M100. However information common to the two cues seems to be extracted for use in a subsequent stage of auditory scene segregation indexed by the object related negativity. This may place a new bound on the extent to which sound location cues are processed in separate channels of the auditory cortex.
Gender differences in navigation performance are associated with differential theta and high-gamma activities in the hippocampus and parahippocampus
Publisher: Elsevier BV
Date: 08-2020
SaMpling Antibiotics in Renal Replacement Therapy (SMARRT): an observational pharmacokinetic study in critically ill patients
Publisher: Springer Science and Business Media LLC
Date: 03-2016
Neuromagnetic and neuroelectric oscillatory responses to acoustic stimulation with broadband noise
Publisher: Elsevier BV
Date: 06-2007
Urinary Neutrophil Gelatinase-Associated Lipocalin as Predictor of Short- or Long-Term Outcomes in Cardiac Surgery Patients
Publisher: Elsevier BV
Date: 12-2015
Measurement of brain function in pre-school children using a custom sized whole-head MEG sensor array
Publisher: Elsevier BV
Date: 03-2010
DOI: 10.1016/J.CLINPH.2009.10.017
Abstract: Conventional whole-head MEG systems have fixed sensor arrays designed to accommodate most adult heads. However arrays optimised for adult brain measurements are suboptimal for research with the significantly smaller heads of young children. We wished to measure brain activity in children using a novel whole-head MEG system custom sized to fit the heads of pre-school-aged children. Auditory evoked fields were measured from seven 4-year-old children in a 64-channel KIT whole-head gradiometer MEG system. The fit of heads in the MEG helmet dewars, defined as the mean of sensor-to-head centre distances, were substantially better for children in the child helmet dewar than in the adult helmet dewar, and were similar to head fits obtained for adults in a conventional adult MEG system. Auditory evoked fields were successfully measured from all seven children and dipole source locations were computed. These results demonstrate the feasibility of routinely measuring neuromagnetic brain function in healthy, awake pre-school-aged children. The advent of child-sized whole-head MEG systems opens new opportunities for the study of cognitive brain development in young children.
Identifying treatment effects in multi-channel measurements in electroencephalographic studies
Publisher: Wiley
Date: 12-2007
Theta oscillations support the interface between language and memory
Publisher: Elsevier BV
Date: 07-2020
Non-identical neural mechanisms for two types of mental transformation
Publisher: Elsevier BV
Date: 2003
DOI: 10.1016/S0028-3932(03)00060-5
Abstract: Reaction times, accuracy and 128-channel event-related potentials (ERPs) were measured from 14 normal, right-handed subjects while they performed two different parity-judgment tasks that require transformations of mental images: a relatively simple task requiring a single transformation (mental letter rotation), and a more complex task involving a coordinated sequence of transformations (mental paper folding). Reaction times increased monotonically with larger angular displacements from the upright (for mental rotation) and with number of squares carried (for mental paper folding). Both the tasks resulted in litude modulation of an approximately 420-700 ms latency ERP component at parietal electrodes. Scalp topographies indicated that right parietal cortex was activated during mental rotation, but bilateral parietal regions were activated during mental paper folding. Our results support the notion of a right hemispheric superiority for tasks involving simple, single mental rotations, but indicate greater involvement of the left hemisphere when a more complex sequence of transformations are required. This task-dependent lability of hemispheric function may account for some of the inconsistent results reported by previous neuroimaging and electrophysiological studies.
Envelope-following responses in MEG and EEG as indices of temporal processing in the human auditory system
Publisher: Elsevier BV
Date: 11-2014
Effect of Dexmedetomidine Added to Standard Care on Ventilator-Free Time in Patients With Agitated Delirium
Publisher: American Medical Association (AMA)
Date: 12-04-2016
Abstract: Effective therapy has not been established for patients with agitated delirium receiving mechanical ventilation. To determine the effectiveness of dexmedetomidine when added to standard care in patients with agitated delirium receiving mechanical ventilation. The Dexmedetomidine to Lessen ICU Agitation (DahLIA) study was a double-blind, placebo-controlled, parallel-group randomized clinical trial involving 74 adult patients in whom extubation was considered inappropriate because of the severity of agitation and delirium. The study was conducted at 15 intensive care units in Australia and New Zealand from May 2011 until December 2013. Patients with advanced dementia or traumatic brain injury were excluded. Bedside nursing staff administered dexmedetomidine (or placebo) initially at a rate of 0.5 µg/kg/h and then titrated to rates between 0 and 1.5 µg/kg/h to achieve physician-prescribed sedation goals. The study drug or placebo was continued until no longer required or up to 7 days. All other care was at the discretion of the treating physician. Ventilator-free hours in the 7 days following randomization. There were 21 reported secondary outcomes that were defined a priori. Of the 74 randomized patients (median age, 57 years 18 [24%] women), 2 withdrew consent later and 1 was found to have been randomized incorrectly, leaving 39 patients in the dexmedetomidine group and 32 patients in the placebo group for analysis. Dexmedetomidine increased ventilator-free hours at 7 days compared with placebo (median, 144.8 hours vs 127.5 hours, respectively median difference between groups, 17.0 hours [95% CI, 4.0 to 33.2 hours] P = .01). Among the 21 a priori secondary outcomes, none were significantly worse with dexmedetomidine, and several showed statistically significant benefit, including reduced time to extubation (median, 21.9 hours vs 44.3 hours with placebo median difference between groups, 19.5 hours [95% CI, 5.3 to 31.1 hours] P < .001) and accelerated resolution of delirium (median, 23.3 hours vs 40.0 hours median difference between groups, 16.0 hours [95% CI, 3.0 to 28.0 hours] P = .01). Using hierarchical Cox modeling to adjust for imbalanced baseline characteristics, allocation to dexmedetomidine was significantly associated with earlier extubation (hazard ratio, 0.47 [95% CI, 0.27-0.82] P = .007). Among patients with agitated delirium receiving mechanical ventilation in the intensive care unit, the addition of dexmedetomidine to standard care compared with standard care alone (placebo) resulted in more ventilator-free hours at 7 days. The findings support the use of dexmedetomidine in patients such as these. clinicaltrials.gov Identifier: NCT01151865.
Femoral Access and Delivery of Continuous Renal Replacement Therapy Dose
Publisher: S. Karger AG
Date: 20-10-2016
DOI: 10.1159/000439581
Abstract: b i Aims: /i /b The study aims to describe the use of dialysis catheters in critically ill patients treated with continuous renal replacement therapy (CRRT) and to study the impact of femoral versus non-femoral access on CRRT dose. b i Methods: /i /b Statistical analysis and predictive modelling of data from the Randomized Evaluation of Normal vs. Augmented Level renal replacement therapy trial. b i Results: /i /b The femoral vein was the first access site in 937 (67%) of 1,399 patients. These patients had higher Acute Physiology and Chronic Health Evaluation and Sequential Organ Failure Assessment scores (p = 0.009) and lower pH (p 0.001) but similar mortality to patients with non-femoral access (44 vs. 45% p = 0.63). Lower body weight was independently associated with femoral access placement (OR 0.97, 95% CI 0.96-0.98). Femoral access was associated with a 1.03% lower CRRT dose (p = 0.05), but a 4.20% higher dose was achieved with 13.5 Fr catheters (p = 0.03). b i Conclusions: /i /b Femoral access was preferred in lighter and sicker patients. Catheter gauge had greater impact than catheter site in CRRT dose delivery. Video Journal Club “Cappuccino with Claudio Ronco” at www.karger.com/?doi=439581.
Neural activity associated with binaural processes for the perceptual segregation of pitch
Publisher: Elsevier BV
Date: 12-2003
DOI: 10.1016/S1388-2457(03)00247-5
Abstract: We measured late cortical potentials in a psychophysical procedure for binaural unmasking of a dichotically-embedded pitch. Late-latency auditory evoked potentials were measured from 128 recording channels in 13 healthy subjects. Control stimuli consisted of 500 ms segments of broadband acoustic noise presented identically to both ears via earphones, evoking a perception of noise localized in the centre of the head. Dichotic pitch stimuli were created by introducing a dichotic delay to a narrow frequency region of the same noise segments, and resulted in a perception of both the centrally-located noise and a right-lateralized pitch. Both stimuli evoked late auditory event-related potentials (ERPs) characterized by a P1-N1-P2 complex of waves between 60 and 180 ms after stimulus onset. ERPs associated with the control and dichotic pitch stimuli showed no litude differences for the P1 and N1 waves. ERPs to dichotic pitch stimuli became significantly more negative beginning at a latency around 150 ms, an effect that was maximal between 210 and 280 ms. Topographic mapping showed that this late negativity was lateralized to the left hemisphere. The late negative wave elicited by the dichotic pitch stimulus reflects neural processing that is dependent upon binaural fusion within the auditory system. The dichotic pitch paradigm may provide a useful tool for the electrophysiological assessment and study of the temporal processing capabilities of the auditory system. This paradigm may also be useful for the study of binaural mechanisms for the perceptual segregation of concurrent sound sources.
Dual temporal encoding mechanisms in human auditory cortex: Evidence from MEG and EEG
Publisher: Elsevier BV
Date: 03-2016
DOI: 10.1016/J.NEUROIMAGE.2015.12.053
Abstract: Current hypotheses about language processing advocate an integral relationship between encoding of temporal information and linguistic processing in the brain. All such explanations must accommodate the evident ability of the perceptual system to process both slow and fast time scales in speech. However most cortical neurons are limited in their capability to precisely synchronise to temporal modulations at rates faster than about 50Hz. Hence, a central question in auditory neurophysiology concerns how the full range of perceptually relevant modulation rates might be encoded in the cerebral cortex. Here we show with concurrent noninvasive magnetoencephalography (MEG) and electroencephalography (EEG) measurements that the human auditory cortex transitions between a phase-locked (PL) mode of responding to modulation rates below about 50Hz, and a non-phase-locked (NPL) mode at higher rates. Precisely such dual response modes are predictable from the behaviours of single neurons in auditory cortices of non-human primates. Our data point to a common mechanistic explanation for the single neuron and MEG/EEG results and support the hypothesis that two distinct types of neuronal encoding mechanisms are employed by the auditory cortex to represent a wide range of temporal modulation rates. This dual encoding model allows slow and fast modulations in speech to be processed in parallel and is therefore consistent with theoretical frameworks in which slow temporal modulations (such as rhythm or syllabic structure) are akin to the contours or edges of visual objects, whereas faster modulations (such as periodicity pitch or phonemic structure) are more like visual texture.
Musical imagery depends upon coordination of auditory and sensorimotor brain activity
Publisher: Springer Science and Business Media LLC
Date: 14-11-2019
DOI: 10.1038/S41598-019-53260-9
Abstract: Recent magnetoencephalography (MEG) studies have established that sensorimotor brain rhythms are strongly modulated during mental imagery of musical beat and rhythm , suggesting that motor regions of the brain are important for temporal aspects of musical imagery. The present study examined whether these rhythms also play a role in non-temporal aspects of musical imagery including musical pitch . Brain function was measured with MEG from 19 healthy adults while they performed a validated musical pitch imagery task and two non-imagery control tasks with identical temporal characteristics. A 4-dipole source model probed activity in bilateral auditory and sensorimotor cortices. Significantly greater β-band modulation was found during imagery compared to control tasks of auditory perception and mental arithmetic. Imagery-induced β-modulation showed no significant differences between auditory and sensorimotor regions, which may reflect a tightly coordinated mode of communication between these areas. Directed connectivity analysis in the θ-band revealed that the left sensorimotor region drove left auditory region during imagery onset. These results add to the growing evidence that motor regions of the brain are involved in the top-down generation of musical imagery, and that imagery-like processes may be involved in musical perception.
Prior exposure to speech rapidly modulates cortical processing of high-level linguistic structure
Publisher: Cold Spring Harbor Laboratory
Date: 25-01-2022
DOI: 10.1101/2022.01.25.477669
Abstract: Neural activity has been shown to track hierarchical linguistic units in connected speech and these responses can be directly modulated by changes in speech intelligibility caused by spectral degradation. In the current study, we manipulate prior knowledge to increase the intelligibility of physically identical speech sentences and test the hypothesis that the tracking responses can be enhanced by this intelligibility improvement. Cortical magnetoencephalography (MEG) responses to intelligible speech followed by either the same (matched) or different (unmatched) unintelligible speech were measured in twenty-three normal hearing participants. Driven by prior knowledge, cortical coherence to “abstract” linguistic units with no accompanying acoustic cues (phrases and sentences) was enhanced relative to the unmatched condition, and was lateralized to the left hemisphere. In contrast, cortical responses coherent to word units, aligned with acoustic onsets, were bilateral and insensitive to contextual information changes. No such coherence changes were observed when prior experience was not available (unintelligible speech before intelligible speech). This dissociation suggests that cerebral responses to linguistic information are directly affected by intelligibility, which in turn are powerfully shaped by physical cues in speech. These results provide an objective and sensitive neural index of speech intelligibility, and explain why previous studies have reported no effect of prior knowledge on cortical entrainment.
The Complexities of Intravenous Fluid Research: Questions of Scale, Volume, and Accumulation
Publisher: The Korean Society of Critical Care Medicine
Date: 30-11-2016
Sequential processing of interaural timing differences for sound source segregation and spatial localization
Publisher: Wiley
Date: 22-05-2007
DOI: 10.1111/J.1469-8986.2007.00535.X
Abstract: Cortical processing of interaural timing differences (ITDs) was investigated with event-related potential (ERP) measurements in 16 human participants who were required in separate tasks to detect or to spatially localize dichotically embedded pitches. ITDs elicited three ERP components labeled ORN, N2, and P400. The ORN occurred at a latency of 150-250 ms and was elicited by ITDs regardless of location or task. In contrast, the N2 response (250-350 ms) was strongly modulated by location and showed larger litudes for the localization task than for the detection task. Finally, ITDs in the detection task elicited a P400 at a latency of 400-500 ms, but this response was entirely absent from ERPs elicited by identical stimuli in the localization task. These results are consistent with a sequential model of auditory perception in which segregation of concurrent sounds is followed by domain-specific processing of object location and identity.
The effects of impulsivity and proactive inhibition on reactive inhibition and the go process: insights from vocal and manual stop signal tasks
Publisher: Frontiers Media SA
Date: 06-10-2015
Nasal high-flow oxygen therapy in ICU: A before-and-after study
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.AUCC.2015.05.003
Abstract: Non-intubated intensive care patients commonly receive supplemental oxygen by high-flow face mask (HFFM), simple face mask (FM) and nasal prongs (NP) during their ICU admission. However, high-flow nasal prongs (HFNP) offer considerable performance capabilities that may sufficiently meet all their oxygen therapy requirements. To assess the feasibility, safety and cost-effectiveness of introducing a protocol in which HFNP was the primary oxygen delivery device for non-intubated intensive care patients. Prospective 4-week before-and-after study (6 months apart) for all adult patients admitted to a 22-bed tertiary ICU in Melbourne, Australia. 117 patients (57 before, 60 after) were included: 86 (73.5%) received mechanical ventilation. Feasibility revealed a significant reduction in HFFM (52.6-0%, p<.001), FM (35.1-8.3%, p=.002) and NP (75.4-36.7%, p<.001) use and an increase in HFNP use (31.6-81.7%, p<.05) during the after period. Following extubation, there was a significant reduction in HFFM use (65.7% vs. 0%, p<.05) and an increase HFNP use (8.6% vs. 87.5%, p<.05). Costing was in favour of the after period with a consumable cost saving per patient (AUD $32.56 vs. $17.62, p<.05). During the after period, more patients were discharged from ICU with HFNP than during the before period (5 vs. 33 patients, p<.05) and fewer patients (5 vs. 14 patients) used three or more oxygen delivery devices. Safety outcomes demonstrated no significant difference in the number of intubations, re-intubations, readmissions or non-invasive ventilation use between the two time periods. Using HFNP as the primary oxygen delivery method for non-intubated intensive care patients was feasible, appeared safe, and the oxygen device costs were reduced. The findings of our single-centre study support further multi-centre evaluations of HFNP therapy protocols in non-ventilated intensive care patients.
Electroencephalogram Signal Clustering With Convex Cooperative Games
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2022
Neuromagnetic imaging reveals timing of volitional and anticipatory motor control in bimanual load lifting
Publisher: Elsevier BV
Date: 06-2013
DOI: 10.1016/J.BBR.2013.03.020
Abstract: During bimanual load lifting, the brain not only contends with muscle activations in the load-lifting arm, but also has to pre-emptively modulate muscle activations in the load-bearing arm with temporal precision in order to minimize upward arm deflection. Premature or late inhibition in the load-bearing arm activity would result in augmented arm deflection. Little is currently known about the timing operation of motor systems subserving coordinated, bimanual actions. In this study, we measured neuromagnetic brain activity with whole-head magnetoencephalography while 15 participants performed a bimanual load-lifting task. To investigate neural processes prior to load lifting, a beamformer was applied to 6 contiguous 200 ms time epochs spanning the entire premovement phase of the motor task. The sequence of neural activations, following a signal to lift the weight, was chronologically ordered: firstly, the primary motor cortex contralateral to the load-lifting arm was activated, then the cerebellum, and lastly, the basal ganglia, thalamus and primary- re- motor areas contralateral to the load-bearing arm. The current data extend our understanding of the neural underpinnings of bimanual coordination. A model is proposed to account for the central organization of volitional and anticipatory motor control in bimanual load lifting.
Multimodal functional imaging of motor imagery using a novel paradigm
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.NEUROIMAGE.2013.01.001
Abstract: Neuroimaging studies have shown that the neural mechanisms of motor imagery (MI) overlap substantially with the mechanisms of motor execution (ME). Surprisingly, however, the role of several regions of the motor circuitry in MI remains controversial, a variability that may be due to differences in neuroimaging techniques, MI training, instruction types, or tasks used to evoke MI. The objectives of this study were twofold: (i) to design a novel task that reliably invokes MI, provides a reliable behavioral measure of MI performance, and is transferable across imaging modalities and (ii) to measure the common and differential activations for MI and ME with functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG). We present a task in which it is difficult to give accurate responses without the use of either motor execution or motor imagery. The behavioral results demonstrate that participants performed similarly on the task when they imagined vs. executed movements and this performance did not change over time. The fMRI results show a spatial overlap of MI and ME in a number of motor and premotor areas, sensory cortices, cerebellum, inferior frontal gyrus, and ventrolateral thalamus. MI uniquely engaged bilateral occipital areas, left parahippoc us, and other temporal and frontal areas, whereas ME yielded unique activity in motor and sensory areas, cerebellum, precuneus, and putamen. The MEG results show a robust event-related beta band desynchronization in the proximity of primary motor and premotor cortices during both ME and MI. Together, these results further elucidate the neural circuitry of MI and show that our task robustly and reliably invokes motor imagery, and thus may prove useful for interrogating the functional status of the motor circuitry in patients with motor disorders.
Auditory processing in the dyslexic brain
Publisher: Macquarie Centre for Cognitive Science
Date: 2010
DOI: 10.5096/ASCS200944
Vocal response inhibition is enhanced by anodal tDCS over the right prefrontal cortex
Publisher: Springer Science and Business Media LLC
Date: 29-09-2016
DOI: 10.1007/S00221-015-4452-0
Abstract: Stopping outright (reactive inhibition) and slowing down (proactive inhibition) are types of response inhibition which have mainly been investigated in the manual effector system. This study compared reactive inhibition across manual and vocal effector systems, examined the effects of excitatory anodal transcranial direct current stimulation (anodal tDCS) over the right prefrontal cortex (right-PFC) and looked at the relationship between reactive and proactive inhibition. We hypothesised (1) that vocal reactive inhibition would be less effective than manual reactive inhibition as evidenced by longer stop signal reaction times (2) that anodal tDCS would enhance both vocal and manual reactive inhibitions and (3) that proactive and reactive inhibitions would be positively related. We tested 14 participants over two sessions (one session with anodal tDCS and one session with sham stimulation) and applied stimulation protocol in the middle of the session, i.e. only during the second of three phases. We used a stop signal task across two stop conditions: relevant and irrelevant stop conditions in which stopping was required or ignored, respectively. We found that reactive inhibition was faster during and immediately after anodal tDCS relative to sham. We also found that greater level of proactive inhibition enhanced reactive inhibition (indexed by shorter stop signal reaction times). These results support the hypothesis that the right-PFC is part of a core network for reactive inhibition and supports previous contention that proactive inhibition is possibly modulated via preactivating the reactive inhibition network.
High-gamma activity in the human hippocampus and parahippocampus during inter-trial rest periods of a virtual navigation task
Publisher: Elsevier BV
Date: 09-2018
DOI: 10.1016/J.NEUROIMAGE.2018.05.029
Abstract: In rodents, hippoc al cell assemblies formed during learning of a navigation task are observed to re-emerge during resting (offline) periods, accompanied by high-frequency oscillations (HFOs). This phenomenon is believed to reflect mechanisms for strengthening newly-formed memory traces. Using magnetoencephalography recordings and a beamforming source location algorithm (synthetic aperture magnetometry), we investigated high-gamma (80-140 Hz) oscillations in the hippoc al region in 18 human participants during inter-trial rest periods in a virtual navigation task. We found right hippoc al gamma oscillations mirrored the pattern of theta power in the same region during navigation, varying as a function of environmental novelty. Gamma power during inter-trial rest periods was positively correlated with theta power during navigation in the first task set when the environment was new and predicted greater performance improvement in the subsequent task set two where the environment became familiar. These findings provide evidence for human hippoc al reactivation accompanied by high-gamma activities immediately after learning and establish a link between hippoc al high-gamma activities and subsequent memory performance.
Lateralized cerebral processing of abstract linguistic structure in clear and degraded speech
Publisher: Oxford University Press (OUP)
Date: 09-09-2021
Abstract: Human cortical activity measured with magnetoencephalography (MEG) has been shown to track the temporal regularity of linguistic information in connected speech. In the current study, we investigate the underlying neural sources of these responses and test the hypothesis that they can be directly modulated by changes in speech intelligibility. MEG responses were measured to natural and spectrally degraded (noise-vocoded) speech in 19 normal hearing participants. Results showed that cortical coherence to “abstract” linguistic units with no accompanying acoustic cues (phrases and sentences) were lateralized to the left hemisphere and changed parametrically with intelligibility of speech. In contrast, responses coherent to words/syllables accompanied by acoustic onsets were bilateral and insensitive to intelligibility changes. This dissociation suggests that cerebral responses to linguistic information are directly affected by intelligibility but also powerfully shaped by physical cues in speech. This explains why previous studies have reported widely inconsistent effects of speech intelligibility on cortical entrainment and, within a single experiment, provided clear support for conclusions about language lateralization derived from a large number of separately conducted neuroimaging studies. Since noise-vocoded speech resembles the signals provided by a cochlear implant device, the current methodology has potential clinical utility for assessment of cochlear implant performance.
Use of multiple dipole analysis for the classification of benign rolandic epilepsy
Publisher: Springer Science and Business Media LLC
Date: 1990
DOI: 10.1007/BF01128875
Liberal Glycemic Control in Critically Ill Patients with Type 2 Diabetes
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2016
DOI: 10.1097/CCM.0000000000001815
Abstract: The optimal blood glucose target in critically ill patients with preexisting diabetes and chronic hyperglycemia is unknown. In such patients, we aimed to determine whether a “ liberal” approach to glycemic control would reduce hypoglycemia and glycemic variability and appear safe. Prospective, open-label, sequential-period exploratory study. Medical-surgical ICU. During sequential 6-month periods, we studied 83 patients with preexisting type 2 diabetes and chronic hyperglycemia (glycated hemoglobin, ≥ 7.0% at ICU admission). During the “standard care” period, 52 patients received insulin to treat blood glucose concentrations greater than 10 mmol/L whereas during the “liberal” period, 31 patients received insulin to treat blood glucose concentrations greater than 14 mmol/L. Time-weighted mean glucose concentrations and the number and duration of moderate ( 4.0 mmol/L) and severe (≤ 2.2 mmol/L) hypoglycemic episodes were recorded, with moderate and severe hypoglycemic episodes grouped together. Glycemic variability was assessed by calculating the coefficient of variability for each patient. Safety was evaluated using clinical outcomes and plasma concentrations of markers of inflammation, glucose-turnover, and oxidative stress. Mean glucose (TWglucose day 0–7 , standard care: 9.3 [1.8] vs liberal: 10.3 [2.1] mmol/L p = 0.02) and nadir blood glucose (4.4 [1.5] vs 5.5 [1.6] mmol/L p 0.01) were increased during the liberal period. There was a signal toward reduced risk of moderate-severe hypoglycemia (relative risk: liberal compared with standard care: 0.47 [95% CI, 0.19–1.13] p = 0.09). Ten patients (19%) during the standard period and one patient (3%) during the liberal period had recurrent episodes of moderate-severe hypoglycemia. Liberal therapy reduced glycemic variability (coefficient of variability, 33.2% [12.9%] vs 23.8% [7.7%] p 0.01). Biomarker data and clinical outcomes were similar. In critically ill patients with type 2 diabetes and chronic hyperglycaemia, liberal glycemic control appears to attenuate glycemic variability and may reduce the prevalence of moderate-severe hypoglycemia.
An EEG/MEG study of anticipatory postural adjustment in a bimanual load-lifting task
Publisher: Macquarie Centre for Cognitive Science
Date: 2010
DOI: 10.5096/ASCS200940
Development of face recognition
Publisher: Elsevier BV
Date: 04-2018
Brain EEG time-series clustering using maximum-weight clique
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2022
High-density mapping in an N400 paradigm: evidence for bilateral temporal lobe generators
Publisher: Elsevier BV
Date: 03-2000
DOI: 10.1016/S1388-2457(99)00270-9
Abstract: The aim of this study was to obtain a more detailed description of N400 scalp topography than has previously been reported. High-density (128 channel) visual event-related potentials were measured in an N400 paradigm using semantically incongruous sentence endings. The stimuli elicited an N400 with a centroparietal scalp distribution. In addition, P400s with similar timing and functional characteristics were observed at non-standard recording locations inferior to the temporal lobes. The data are consistent with intracranial evidence for bilateral activation of anterior medial temporal lobe structures. These structures are oriented such that the positive regions of their scalp fields lie largely outside of the area s led by standard electrode montages. P400s at other non-standard scalp locations, including infraorbital and infraoccipital sites, may reflect volume conduction from the same generators, or activation of non-temporal lobe generators.
Atypical brain responses to illusory auditory pitch in children with autism
Publisher: SAGE Publications
Date: 07-2012
Speech kinematics and coordination measured with an MEG-compatible speech tracking system
Publisher: Frontiers Media SA
Date: 28-06-2022
DOI: 10.3389/FNEUR.2022.828237
Abstract: Articulography and functional neuroimaging are two major tools for studying the neurobiology of speech production. Until recently, however, it has generally not been possible to use both in the same experimental setup because of technical incompatibilities between the two methodologies. Here we describe results from a novel articulography system dubbed Magneto-articulography for the Assessment of Speech Kinematics (MASK), which we used to derive kinematic profiles of oro-facial movements during speech. MASK was used to characterize speech kinematics in two healthy adults, and the results were compared to measurements from a separate participant with a conventional Electromagnetic Articulography (EMA) system. Analyses targeted the gestural landmarks of reiterated utterances /ipa/, /api/ and ataka/. The results demonstrate that MASK reliably characterizes key kinematic and movement coordination parameters of speech motor control. Since these parameters are intrinsically registered in time with concurrent magnetoencephalographic (MEG) measurements of neuromotor brain activity, this methodology paves the way for innovative cross-disciplinary studies of the neuromotor control of human speech production, speech development, and speech motor disorders.
Targeted therapeutic mild hypercapnia after cardiac arrest: A phase II multi-centre randomised controlled trial (the CCC trial)
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.RESUSCITATION.2016.03.023
Abstract: In intensive care observational studies, hypercapnia after cardiac arrest (CA) is independently associated with improved neurological outcome. However, the safety and feasibility of delivering targeted therapeutic mild hypercapnia (TTMH) for such patients is untested. In a phase II safety and feasibility multi-centre, randomised controlled trial, we allocated ICU patients after CA to 24h of targeted normocapnia (TN) (PaCO2 35-45mmHg) or TTMH (PaCO2 50-55mmHg). The primary outcome was serum neuron specific enolase (NSE) and S100b protein concentrations over the first 72h assessed in the first 50 patients surviving to day three. Secondary end-points included global measure of function assessment at six months and mortality for all patients. We enrolled 86 patients. Their median age was 61 years (58, 64 years) and 66 (79%) were male. Of these, 50 patients (58%) survived to day three for full biomarker assessment. NSE concentrations increased in the TTMH group (p=0.02) and TN group (p=0.005) over time, with the increase being significantly more pronounced in the TN group (p(interaction)=0.04). S100b concentrations decreased over time in the TTMH group (p<0.001) but not in the TN group (p=0.68). However, the S100b change over time did not differ between the groups (p(interaction)=0.23). At six months, 23 (59%) TTMH patients had good functional recovery compared with 18 (46%) TN patients. Hospital mortality occurred in 11 (26%) TTMH patients and 15 (37%) TN patients (p=0.31). In CA patients admitted to the ICU, TTMH was feasible, appeared safe and attenuated the release of NSE compared with TN. These findings justify further investigation of this novel treatment.
The ICU Mobility Scale Has Construct and Predictive Validity and Is Responsive. A Multicenter Observational Study
Publisher: American Thoracic Society
Date: 06-2016
Movement‐related neuromagnetic fields in preschool age children
Publisher: Wiley
Date: 03-04-2014
DOI: 10.1002/HBM.22518
“Shut up!” An electrophysiological study investigating the neural correlates of vocal inhibition
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2011.11.009
Abstract: A neural biomarker that can be applied to studies of oral communication disorders would provide a boon to researchers. While there has been much research conducted on manual response inhibition, very few studies have examined vocal response inhibition. To date, no study has examined the temporal aspects of vocal inhibition. Therefore, the present study attempted to identify the neural correlates of vocal response inhibition by recording electroencephalographic activity during a modified version of the stop signal task. We included an ignore signal condition matched for frequency and visual stimulation to the stop signal which importantly, was included in the same block of trials as the typical go and stop trials. Behavioural results showed that participants were able to inhibit a vocal response within approximately 324 ms. Statistical analysis of ERPs revealed that a positive component around 324 ms was significantly larger in litude during successfully stopped trials compared to in an ignore condition, particularly over a cluster of fronto-central electrodes. These results support the notion that the P3 component is a reliable index of vocal inhibition.
Development of effective connectivity in the core network for face perception
Publisher: Wiley
Date: 19-02-2015
DOI: 10.1002/HBM.22762
The functional role of human right hippocampal/parahippocampal theta rhythm in environmental encoding during virtual spatial navigation
Publisher: Wiley
Date: 04-11-2017
DOI: 10.1002/HBM.23458
Atelectasis and mechanical ventilation mode during conservative oxygen therapy
Publisher: Elsevier BV
Date: 12-2015
Abnormal time course of low beta modulation in non-fluent preschool children: A magnetoencephalographic study of rhythm tracking
Publisher: Elsevier BV
Date: 2016
DOI: 10.1016/J.NEUROIMAGE.2015.10.086
Abstract: Stuttering is a disorder of speech affecting millions of people around the world. Whilst the exact aetiology of stuttering remains unknown, it has been hypothesised that it is a disorder of the neural mechanisms that support speech timing. In this article, we used magnetoencephalography (MEG) to examine activity from auditory regions of the brain in stuttering and non-stuttering children aged 3-9years. For typically developing children, we found that MEG oscillations in the beta band responded to rhythmic sounds with a peak near the time of stimulus onset. In contrast, stuttering children showed an opposite phase of beta band envelope, with a trough of activity at stimulus onset. These results suggest that stuttering may result from abnormalities in predictive brain responses which are reflected in abnormal entrainment of the beta band envelope to rhythmic sounds.
How the brain responds to any: An MEG study
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.BANDL.2011.08.006
Abstract: The word any may appear in some sentences, but not in others. For ex le, any is permitted in sentences that contain the word nobody, as in Nobody ate any fruit. However, in a minimally different context any seems strikingly anomalous: (*)Everybody ate any fruit. The aim of the present study was to investigate how the brain responds to the word any in such minimally different contexts - where it is permitted (licensed) and where it is not permitted (unlicensed). Brain responses were measured from adult readers using magnetoencephalography (MEG). The results showed significantly larger responses to permissible contexts in the left posterior temporal areas between 400-500 ms and 590-660 ms. These results clarify the anatomy and timing of brain processes that contribute to our judgment that a word such as any is or is not permitted in a given context.
Sound envelope processing in the developing human brain: A MEG study
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.CLINPH.2015.07.038
Abstract: This study investigated auditory cortical processing of linguistically-relevant temporal modulations in the developing brains of young children. Auditory envelope following responses to white noise litude modulated at rates of 1-80 Hz in healthy children (aged 3-5 years) and adults were recorded using a paediatric magnetoencephalography (MEG) system and a conventional MEG system, respectively. For children, there were envelope following responses to slow modulations but no significant responses to rates higher than about 25 Hz, whereas adults showed significant envelope following responses to almost the entire range of stimulus rates. Our results show that the auditory cortex of preschool-aged children has a sharply limited capacity to process rapid litude modulations in sounds, as compared to the auditory cortex of adults. These neurophysiological results are consistent with previous psychophysical evidence for a protracted maturational time course for auditory temporal processing. The findings are also in good agreement with current linguistic theories that posit a perceptual bias for low frequency temporal information in speech during language acquisition. These insights also have clinical relevance for our understanding of language disorders that are associated with difficulties in processing temporal information in speech.
A Binational Multicenter Pilot Feasibility Randomized Controlled Trial of Early Goal-Directed Mobilization in the ICU*
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2016
DOI: 10.1097/CCM.0000000000001643
Abstract: To determine if the early goal-directed mobilization intervention could be delivered to patients receiving mechanical ventilation with increased maximal levels of activity compared with standard care. A pilot randomized controlled trial. Five ICUs in Australia and New Zealand. Fifty critically ill adults mechanically ventilated for greater than 24 hours. Patients were randomly assigned to either early goal-directed mobilization (intervention) or to standard care (control). Early goal-directed mobilization comprised functional rehabilitation treatment conducted at the highest level of activity possible for that patient assessed by the ICU mobility scale while receiving mechanical ventilation. The ICU mobility scale, strength, ventilation duration, ICU and hospital length of stay, and total inpatient (acute and rehabilitation) stay as well as 6-month post-ICU discharge health-related quality of life, activities of daily living, and anxiety and depression were recorded. The mean age was 61 years and 60% were men. The highest level of activity (ICU mobility scale) recorded during the ICU stay between the intervention and control groups was mean (95% CI) 7.3 (6.3–8.3) versus 5.9 (4.9–6.9), p = 0.05. The proportion of patients who walked in ICU was almost doubled with early goal-directed mobilization (intervention n = 19 [66%] vs control n = 8 [38%] p = 0.05). There was no difference in total inpatient stay (d) between the intervention versus control groups (20 [15–35] vs 34 [18–43] p = 0.37). There were no adverse events. Key Practice Points: Delivery of early goal-directed mobilization within a randomized controlled trial was feasible, safe and resulted in increased duration and level of active exercises.
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