ORCID Profile
0000-0002-6975-8958
Current Organisation
Deakin University
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Psychology | Philosophy of Cognition | Sensory Processes, Perception and Performance | Developmental Psychology and Ageing | Social and Community Psychology
Expanding Knowledge in Psychology and Cognitive Sciences | Expanding Knowledge in the Biological Sciences | Expanding Knowledge in Philosophy and Religious Studies |
Publisher: Wiley
Date: 08-2015
DOI: 10.1002/JTS.22030
Abstract: Although the experience of vicarious sensations when observing another in pain have been described post utation, the underlying mechanisms are unknown. We investigated whether vicarious sensations are related to posttraumatic stress disorder (PTSD) symptoms and chronic pain. In Study 1, 236 utees completed questionnaires about phantom limb phenomena and vicarious sensations to both innocuous and painful sensory experiences of others. There was a 10.2% incidence of vicarious sensations, which was significantly more prevalent in utees reporting PTSD-like experiences, particularly increased arousal and reexperiencing the event that led to utation (φ = .16). In Study 2, 63 utees completed the Empathy for Pain Scale and PTSD Checklist-Civilian Version. Cluster analyses revealed 3 groups: 1 group did not experience vicarious pain or PTSD symptoms, and 2 groups were vicarious pain responders, but only 1 had increased PTSD symptoms. Only the latter group showed increased chronic pain severity compared with the nonresponder group (p = .025) with a moderate effect size (r = .35). The findings from both studies implicated an overlap, but also ergence, between PTSD symptoms and vicarious pain reactivity post utation. Maladaptive mechanisms implicated in severe chronic pain and physical reactivity posttrauma may increase the incidence of vicarious reactivity to the pain of others.
Publisher: Springer Science and Business Media LLC
Date: 22-03-2006
DOI: 10.1007/S00787-006-0530-Y
Abstract: Gait abnormalities have been widely reported in in iduals with autism and Asperger's disorder. There is controversy as to whether the cerebellum or the basal-ganglia frontostriatal regions underpin these abnormalities. This is the first direct comparison of gait and upper-body postural features in autism and Asperger's disorder. Clinical and control groups were matched according to age, height, weight, performance, and full scale IQ. Consistent with Hallet's (1993) cerebellar-gait hypothesis, the autistic group showed significantly increased stride-length variability in their gait in comparison to control and Asperger's disorder participants. No quantitative gait deficits were found for the Asperger's disorder group. In support of Damasio and Maurer's (1982) basal-ganglia frontostriatal-gait hypothesis, both clinical groups were rated as showing abnormal arm posturing, however, only the Asperger's group were rated as significantly different from controls in terms of head and trunk posturing. While DSM-IV-TR suggests that Asperger's disorder, but not autism, is associated with motoric clumsiness, our data suggest that both clinical groups are uncoordinated and lacking in motor smoothness. Gait differences in autism and Asperger's disorder were suggested to reflect differential involvement of the cerebellum, with commonalities reflecting similar involvement of the basal-ganglia frontostriatal region.
Publisher: Elsevier BV
Date: 04-2011
Publisher: Informa UK Limited
Date: 02-2019
DOI: 10.1080/17470919.2019.1572648
Abstract: Prior studies have demonstrated that aspects of social cognition can be modulated via temporoparietal junction (TPJ) transcranial direct current stimulation (tDCS). However, this technique lacks focality and electrophysiological effects or correlates are rarely examined. The present study investigated whether anodal and/or cathodal high-definition tDCS (HD-tDCS) would influence facial emotion processing performance relative to sham stimulation, and whether task performance changes were related to neurophysiological changes. Participants completed a facial emotion attribution tasks before and after rTPJ HD-tDCS, with event-related potentials (ERP) recorded during task performance. Anodal rTPJ HD-tDCS improved facial emotion processing performance for static depictions of fear (but not surprise). Stimulation condition influenced P300 latency, and also influenced the relationship between behavioural and electrophysiological (ERP) outcomes in several circumstances, findings which both support and challenge anodal-excitation/cathodal-inhibition accounts of tDCS effects. Results suggest that rTPJ anodal HD-tDCS can influence facial emotion recognition (i.e., affective mentalizing), and elucidate the nature and distribution of underlying neurophysiological processes. Stimulation effects, however, might depend on the intensity and salience/valence (negativity/threat) of the emotion, and these behavioural effects may not relate directly or simply to the ERPs assessed here.
Publisher: Elsevier BV
Date: 09-2008
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2008.04.022
Abstract: Theoretical accounts suggest that mirror neurons play a crucial role in social cognition. The current study used transcranial magnetic stimulation (TMS) to investigate the association between mirror neuron activation and facial emotion processing, a fundamental aspect of social cognition, among healthy adults (n=20). Facial emotion processing of static (but not dynamic) images correlated significantly with an enhanced motor response, proposed to reflect mirror neuron activation. These correlations did not appear to reflect general facial processing or pattern recognition, and provide support to current theoretical accounts linking the mirror neuron system to aspects of social cognition. We discuss the mechanism by which mirror neurons might facilitate facial emotion recognition.
Publisher: Wiley
Date: 25-03-2019
DOI: 10.1111/EJN.14370
Abstract: Mirror neurons (MN) have been proposed as the neural substrate for a wide range of clinical, social and cognitive phenomena. Over the last decade, a commonly used tool for investigating MN activity in the human brain has been functional magnetic resonance (fMRI) repetition suppression (RS) paradigms. However, the available evidence is mixed, largely owing to inconsistent application of the methodological criteria necessary to infer MN properties. This raises concerns about the degree to which one can infer the presence (or absence) of MN activity from earlier accounts that adopted RS paradigms. We aimed to clarify this issue using a well-validated fMRI RS paradigm and tested for mirror properties by rigorously applying the widely accepted criteria necessary to demonstrate MN activity using traditional univariate techniques and Multivariate Pattern Analysis (MVPA). While univariate whole brain analysis in healthy adults showed uni-modal RS effects within the supplementary motor area, no evidence for cross-modal RS effects consistent with mirror neuron activity was found. MVPA on the other hand revealed a region along the anterior intraparietal sulcus that met the criteria for MN activity. Taken together, these results clarify disparate evidence from earlier RS studies, highlighting that traditional univariate analysis of RS data may not be sensitive for detecting MN activity when rigorously applying the requisite criteria. In light of these findings, we recommend that short of increasing s le sizes substantially, future studies using RS paradigms to investigate MNs across the human brain consider the use of MVPA.
Publisher: Elsevier BV
Date: 05-2023
Publisher: Frontiers Media SA
Date: 2013
Publisher: American Physiological Society
Date: 10-2019
Abstract: The right temporoparietal junction (rTPJ) is a multisensory integration hub that is increasingly utilized as a target of stimulation studies exploring its rich functional network roles and potential clinical applications. While transcranial direct current stimulation (tDCS) is frequently employed in such studies, there is still relatively little known regarding its local and network neurophysiological effects, particularly at important nonmotor sites such as the rTPJ. The current study applied either anodal, cathodal, or sham high-definition tDCS to the rTPJ of 53 healthy participants and used offline EEG to assess the impacts of stimulation on resting state (eyes open and eyes closed) band power and coherence. Temporoparietal and central region delta power was increased after anodal stimulation (the latter trend only), whereas cathodal stimulation increased frontal region delta and theta power. Increased coherence between right and left temporoparietal regions was also observed after anodal stimulation. All significant effects occurred in the eyes open condition. These findings are discussed with reference to domain general and mechanistic theories of rTPJ function. Low-frequency oscillatory activity may exert long-range inhibitory network influences that enable switching between and integration of endogenous/exogenous processing streams.
Publisher: Mary Ann Liebert Inc
Date: 09-2016
Abstract: Neuroimaging and electrophysiological research have revealed a range of neural abnormalities in autism spectrum disorder (ASD), but a comprehensive understanding remains elusive. We utilized a novel methodology among in iduals with ASD and matched controls, combining transcranial magnetic stimulation (TMS) with concurrent electroencephalogram (EEG) recording (TMS-EEG) to explore cortical function and connectivity in three sites implicated in the neuropathophysiology of ASD (dorsolateral prefrontal cortex, primary motor cortex, and temporoparietal junction). As there is evidence for neurobiological gender differences in ASD, we also examined the influence of biological sex. TMS pulses were applied to each of the three sites (right lateralized) during 20-channel EEG recording. We did not identify any differences in the EEG response to TMS between ASD and control groups. This finding remained when data were stratified by sex. Nevertheless, traits and characteristics associated with ASD were correlated with the neurophysiological response to TMS. While TMS-EEG did not appear to clarify the neuropathophysiology of ASD, the relationships identified between the neurophysiological response to TMS and clinical characteristics warrant further investigation.
Publisher: Informa UK Limited
Date: 20-08-2018
DOI: 10.1080/87565641.2018.1504948
Abstract: The primary aim of this study was to kinematically assess how children with autism spectrum disorder (ASD) plan and control their handwriting actions. Forty-three boys aged between 8 to 12 years were included in the present analysis 23 with ASD and 20 typically developing (TD) controls. Sophisticated objective and quantifiable assessment of movement metrics and dynamics was applied across a series of basic cursive handwriting sequences. Children with ASD demonstrated atypical control of handwriting metrics and dynamics, as well as significantly greater neuromotor noise relative to age-matched peers. They also engaged in less regular monitoring and regulation of their movement during the handwriting task. This study provides new insights into the way children with ASD plan and sequence their handwriting movements. Overall, results revealed that even at a basic level, children with ASD appear to have a breakdown in their ability to control and regulate their handwriting movements. This has important implications for the school-aged child who constantly engages in handwriting tasks within the classroom environment and provides insight into possible directions for future intervention.
Publisher: Elsevier BV
Date: 07-2019
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2011
Publisher: Frontiers Media SA
Date: 2013
Publisher: Elsevier BV
Date: 04-2018
DOI: 10.1016/J.PSCYCHRESNS.2018.02.004
Abstract: Magnetic resonance spectroscopy (MRS) was utilized to investigate sex differences in gamma-aminobutyric acid (GABA) between adults with autism spectrum disorder (ASD) and neurotypical (NT) controls. GABA at the right superior temporal sulcus (STS) is reported for 12 ASD and 14 NT participants. The results show no group differences in GABA. There was, however, a significant positive association between GABA at the STS and autism-related social impairments in females with ASD. These findings provide preliminary support for sex differences in GABAergic distribution and processes that contribute to social functioning in ASD.
Publisher: Frontiers Media SA
Date: 29-03-2018
Publisher: Springer Science and Business Media LLC
Date: 22-12-2012
DOI: 10.1007/S10803-011-1430-7
Abstract: Autism spectrum disorder (ASD) is characterised by differences in unimodal and multimodal sensory and proprioceptive processing, with complex biases towards local over global processing. Many of these elements are implicated in versions of the rubber hand illusion (RHI), which were therefore studied in high-functioning in iduals with ASD and a typically developing control group. Both groups experienced the illusion. A number of differences were found, related to proprioception and sensorimotor processes. The ASD group showed reduced sensitivity to visuotactile-proprioceptive discrepancy but more accurate proprioception. This group also differed on acceleration in subsequent reach trials. Results are discussed in terms of weak top-down integration and precision-accuracy trade-offs. The RHI appears to be a useful tool for investigating multisensory processing in ASD.
Publisher: Cold Spring Harbor Laboratory
Date: 07-08-2019
DOI: 10.1101/728204
Abstract: Several lines of evidence identify aberrant excitatory-inhibitory neural processes across autism and schizophrenia spectrum disorders, particularly within the psychosocial domain. Such neural processes include increased excitatory glutamate and reduced inhibitory GABA concentrations, which may affect auditory pre-attentive processing as indexed by the mismatch negativity (MMN) thus, an excitation-inhibition imbalance might lead to aberrant MMN, which might in turn drive the relationship between the MMN and psychosocial difficulties. This research has the potential to enhance the neurochemical understanding of the relationship between electrophysiology (MMN) and behavioural/clinical measures (psychosocial difficulties). Thirty-eight adults (18 male, 18-40 years) completed the Schizotypal Personality Questionnaire (SPQ) and Autism-Spectrum Quotient (AQ). Glutamate and GABA concentrations in bilateral superior temporal cortex (STC) were quantified using proton magnetic resonance spectroscopy (1H-MRS) while auditory MMN to a duration deviant was measured with magnetoencephalography. Spearman correlations probed the relationships between STC glutamate/GABA ratios, MMN litude and latency, and AQ and SPQ dimensions. Mediation effects of glutamate/GABA ratios on the relationship between MMN and AQ-SPQ dimensions were probed using causal mediation analysis. Only SPQ-interpersonal and AQ-communication were significantly correlated with right hemisphere glutamate/GABA ratios and MMN latency ( p s .05), which were themselves correlated ( p =.038). Two mediation models were investigated, with right MMN latency as predictor and SPQ-interpersonal and AQ-communication as outcome variables. Right STC glutamate/GABA ratios significantly mediated the relationship between MMN latency and SPQ-interpersonal scores (ß=86.6, p =.033), but only partially mediated the relationship between MMN latency and AQ-communication scores (ß=21.0, p =.093). These findings support the growing body of literature pointing toward an excitation-inhibition imbalance that is central to psychosocial functioning across multi-dimensional spectrum disorders, such as autism and schizophrenia, and provides neurochemical indicators of the processes that underlie psychosocial dysfunction.
Publisher: Wiley
Date: 27-09-2023
DOI: 10.1111/JORA.12803
Abstract: Self‐disclosure is a crucial part of developing close interpersonal relationships during adolescence. In particular, sharing information with a greater depth of intimacy is thought to strengthen social bonds and thus support mental health. The current study investigated the value for different depths of self‐disclosures to close others (mothers and best friends) during adolescence and its association with mental health and well‐being. Fifty‐four girls (11.0–15.9 years) completed a forced‐choice monetary paradigm to assess value for self‐disclosures and questionnaires on mental health. Participants significantly valued (i.e., forfeited monetary reward) for disclosures to both mothers and best friends, although intimate disclosures were more “costly” than superficial disclosures. Greater value for intimate self‐disclosures to mothers was also associated with better mental health and well‐being.
Publisher: Elsevier BV
Date: 10-2010
DOI: 10.1016/J.BRS.2010.06.001
Abstract: One of the few novel treatments developed for major depression in recent years has been repetitive transcranial magnetic stimulation (rTMS). Despite mostly promising results, 50-60% of patients do not respond to rTMS. Therefore, it is important to investigate ways of enhancing the effectiveness of this treatment. To date, attempting to enhance the mood effects of rTMS via behavioral means has not been investigated. One such intervention involves concurrent exposure to affective stimuli that have been shown to result in activation of brain regions associated with emotion. This pilot study of ten participants investigates such an intervention. The aim of this pilot study was to investigate whether exposing participants to affective stimuli while they were receiving 5 Hz rTMS resulted in greater mood change compared with rTMS or affective stimuli alone. Ten healthy male and female participants were exposed to affective stimuli while receiving rTMS. All participants took part in three counterbalanced conditions conducted a week apart in which they received rTMS (active or sham) delivered to the left dorsolateral prefrontal cortex (DLPFC) combined with affective stimuli (positive or neutral). To measure the impact of the dual intervention visual analogue mood scales and an affective go no go task were conducted pre- and post intervention for each session. There was no effect of any rTMS condition on performances on the affective go no go task, or on any of the visual analogue scales. The current data do not provide support for the use of affective stimuli during rTMS. Methodological limitations that may have contributed to the lack of significant findings are discussed.
Publisher: Cold Spring Harbor Laboratory
Date: 04-2022
DOI: 10.1101/2022.03.30.22273215
Abstract: Corpus callosum anomalies are commonly noted in autism spectrum disorder (ASD). Given the complexity of its microstructural architecture, with crossing fibers projecting throughout, we applied fixel-based analysis to probe white matter micro- and macrostructure within this region. As ASD is a neurodevelopmental condition with noted abnormalities in brain growth, age was also investigated. Data for participants with (N=54) and without (N=50) ASD, aged 5-34 years, were obtained from the Autism Brain Imaging Data Exchange-II (ABIDE-II). Within each site, indices of fiber density (FD), fiber cross-section (FC), and combined fiber density and cross-section (FDC) were compared between those groups. Young adolescents with ASD (age = 11.19 ± 7.54) showed reduced macroscopic FC and FDC compared to age-matched neurotypical controls (age = 10.04 ± 4.40). Reduced FD and FDC was noted in a marginally older ASD (age 13.87 ± 3.15) cohort compared to matched controls (age = 13.85 ± 2.90). Among the oldest cohorts, a non-significant trend indicated reduced FD in older adolescents/young adults with ASD (age = 17.07 ± 3.56) compared to controls (age = 16.55 ± 2.95). There was a positive correlation between age and callosal mean FC and FDC in the youngest cohort. When stratified by diagnosis, this finding remained only for the ASD s le. White matter aberration appears greatest among younger ASD cohorts. In older adolescents and young adults, less of the corpus callosum seems affected. This supports the suggestion that some early neuropathophysiological indicators in ASD may dissipate with age.
Publisher: Springer Science and Business Media LLC
Date: 27-12-2012
DOI: 10.3758/S13415-011-0080-8
Abstract: Observing noxious injury to another's hand is known to induce corticospinal inhibition that can be measured in the observer's corresponding muscle. Here, we investigated whether acquired pain synesthetes, in iduals who experience actual pain when observing injury to another, demonstrate less corticospinal inhibition than do controls during pain observation, as a potential mechanism for the experience of vicarious pain. We recorded motor-evoked potentials (MEPs) induced at two time points through transcranial magnetic stimulation while participants observed videos of a hand at rest, a hypodermic needle penetrating the skin, a Q-tip touching the skin, and a hypodermic needle penetrating an apple. We compared MEPs in three groups: 7 utees who experience pain synesthesia, 11 nonsynesthete utees who experience phantom limb pain, and 10 healthy controls. Results indicated that the pain synesthete group demonstrated significantly enhanced MEP response to the needle penetrating the hand, relative to the needle not having yet penetrated the hand, as compared with controls. This effect was not observed exclusively in the same muscle where noxious stimulation was applied. We speculate that our findings reflect a generalized response to pain observation arising from hyperactivity of motor mirror neurons not involved in direct one-to-one simulation but, rather, in the representation of another's experience.
Publisher: Elsevier BV
Date: 02-2011
DOI: 10.1016/J.NEULET.2010.11.067
Abstract: The effects of action observation on cortical processes have typically been interpreted in the context of so-called "mirror systems" (i.e., brain regions active during both the experience and observation of behaviour, emotion, or sensation), and viewed as subserving social cognition via a self-other matching mechanism. If such cortical processes do indeed facilitate social understanding, then cortical activity during action observation might be further enhanced when observing behaviour embedded within a social, interactive context. Transcranial magnetic stimulation (TMS) was administered to 27 healthy adults, and corticospinal excitability (CSE), which is a putative measure of the mirror system, was examined during the observation of (1) meaningless behaviour, (2) goal-directed behaviour, and (3) social behaviour. Although CSE was enhanced during the observation of both goal-directed and social behaviour, there was no difference between the two. These findings suggest that while the putative human mirror system is responsive to goal-directed behaviour, it may not be more responsive to behaviour that occurs within a social context.
Publisher: Informa UK Limited
Date: 28-03-2016
DOI: 10.1080/17470919.2016.1166154
Abstract: The dorsolateral prefrontal cortex (DLPFC) is thought to play a key role in the cognitive control of emotion and has therefore, unsurprisingly, been implicated in the regulation of physical pain perception. This brain region may also influence the experience of social pain, which has been shown to activate similar neural networks as seen in response to physical pain. Here, we applied sham or active low-frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) to the left DLPFC, previously shown to exert bilateral effects in pain perception, in healthy participants. Following stimulation, participants played the "Cyberball Task" an online ball-tossing game in which the subject participant is included or excluded. Compared to sham, rTMS did not modulate behavioural response to social exclusion. However, within the active rTMS group only, greater trait personal distress was related to enhanced negative outcomes to social exclusion. These results add further support to the notion that the effect of brain stimulation is not homogenous across in iduals, and indicates the need to consider baseline in idual differences when assessing response to brain stimulation. This seems particularly relevant in social neuroscience investigations, where trait factors may have a meaningful effect.
Publisher: Frontiers Media SA
Date: 09-08-2016
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.NEUBIOREV.2011.09.006
Abstract: Recent research suggests the observation or imagination of somatosensory stimulation in another (e.g., touch or pain) can induce a similar somatosensory experience in oneself. Some researchers have presented this experience as a type of synaesthesia, whereas others consider it an extreme experience of an otherwise normal perception. Here, we present an argument that these descriptions are not mutually exclusive. They may describe the extreme version of the normal process of understanding somatosensation in others. It becomes synaesthesia, however, when this process results in a conscious experience comparable to the observed person's state. We describe these experiences as 'mirror-sensory synaesthesia' a type of synaesthesia identified by its distinct social component where the induced synaesthetic experience is a similar sensory experience to that perceived in another person. Through the operationalisation of this intriguing experience as synaesthesia, existing neurobiological models of synaesthesia can be used as a framework to explore how mechanisms may act upon social cognitive processes to produce conscious experiences similar to another person's observed state.
Publisher: Elsevier BV
Date: 04-2012
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2012.01.036
Abstract: In iduals with anorexia nervosa (AN) demonstrate a relentless engagement in behaviors aimed to reduce their weight, which leads to severe underweight status, and occasionally death. Neurobiological abnormalities, as a consequence of starvation are controversial: evidence, however, demonstrates abnormalities in the reward system of patients, and recovered in iduals. Despite this, a unifying explanation for reward abnormalities observed in AN and their relevance to symptoms of the illness, remains incompletely understood. Theories explaining reward dysfunction have conventionally focused on anhedonia, describing that patients have an impaired ability to experience reward or pleasure. We review taste reward literature and propose that patients' reduced responses to conventional taste-reward tasks may reflect a fear of weight gain associated with the caloric nature of the tasks, rather than an impaired ability to experience reward. Consistent with this, we propose that patients are capable of 'liking' hedonic taste stimuli (e.g., identifying them), however, they do not 'want' or feel motivated for the stimuli in the same way that healthy controls report. Recent brain imaging data on more complex reward processing tasks provide insights into fronto-striatal neural circuit dysfunction related to altered reward processing in AN that challenges the relevance of anhedonia in explaining reward dysfunction in AN. In this way, altered activity of the anterior cingulate cortex and striatum could explain patients' pathological engagement in behaviors they consider rewarding (e.g., self-starvation) that are otherwise aversive or punishing, to those without the eating disorder. Such evidence for altered patterns of brain activity associated with reward processing tasks in patients and recovered in iduals may provide important information about mechanisms underlying symptoms of AN, their future investigation, and the development of treatment approaches.
Publisher: Frontiers Media SA
Date: 24-03-2015
Publisher: Oxford University Press (OUP)
Date: 12-05-2012
DOI: 10.1093/SCAN/NSR016
Publisher: Informa UK Limited
Date: 16-12-2014
DOI: 10.1080/02699931.2013.867832
Abstract: There is substantial evidence for facial emotion recognition (FER) deficits in autism spectrum disorder (ASD). The extent of this impairment, however, remains unclear, and there is some suggestion that clinical groups might benefit from the use of dynamic rather than static images. High-functioning in iduals with ASD (n = 36) and typically developing controls (n = 36) completed a computerised FER task involving static and dynamic expressions of the six basic emotions. The ASD group showed poorer overall performance in identifying anger and disgust and were disadvantaged by dynamic (relative to static) stimuli when presented with sad expressions. Among both groups, however, dynamic stimuli appeared to improve recognition of anger. This research provides further evidence of specific impairment in the recognition of negative emotions in ASD, but argues against any broad advantages associated with the use of dynamic displays.
Publisher: Elsevier BV
Date: 03-2020
DOI: 10.1016/J.PNPBP.2019.109769
Abstract: Several lines of evidence identify aberrant excitatory-inhibitory neural processes across autism and schizophrenia spectrum disorders, particularly within the psychosocial domain. Such neural processes include increased excitatory glutamate and reduced inhibitory GABA concentrations, which may affect auditory pre-attentive processing as indexed by the mismatch negativity (MMN) thus, an excitation-inhibition imbalance might lead to aberrant MMN, which might in turn drive the relationship between the MMN and psychosocial difficulties. This research has the potential to enhance the neurochemical understanding of the relationship between electrophysiology (MMN) and behavioural/clinical measures (psychosocial difficulties). Thirty-eight adults (18 male, 18-40 years) completed the Schizotypal Personality Questionnaire (SPQ) and Autism-Spectrum Quotient (AQ). Glutamate and GABA concentrations in bilateral superior temporal cortex (STC) were quantified using proton magnetic resonance spectroscopy (1H-MRS) while auditory MMN to a duration deviant was measured with magnetoencephalography. Spearman correlations probed the relationships between STC glutamate/GABA ratios, MMN litude and latency, and AQ and SPQ dimensions. Mediation effects of glutamate/GABA ratios on the relationship between MMN and AQ-SPQ dimensions were probed using causal mediation analysis. Only SPQ-interpersonal and AQ-communication were significantly correlated with right hemisphere glutamate/GABA ratios and MMN latency (ps < 0.05), which were themselves correlated (p = .035). Two mediation models were investigated, with right MMN latency as predictor and SPQ-interpersonal and AQ-communication as outcome variables. Right STC glutamate/GABA ratios significantly mediated the relationship between MMN latency and SPQ-interpersonal scores, but only partially mediated the relationship between MMN latency and AQ-communication scores. These findings support the growing body of literature pointing toward an excitation-inhibition imbalance that is central to psychosocial functioning across multi-dimensional spectrum disorders, such as autism and schizophrenia, and provides neurochemical indicators of the processes that underlie psychosocial dysfunction.
Publisher: Frontiers Media SA
Date: 03-06-2014
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.BRS.2011.02.001
Abstract: Motor impairments are common in autism spectrum disorders (ASD). Electrophysiologic studies reveal abnormalities in the preparation of movement repetitive transcranial magnetic stimulation (rTMS) to key motor cortical sites may therefore be a useful technique for improving motor function in ASD. To examine whether rTMS can improve electrophysiologic and behavioral indices of motor activity. Eleven participants with ASD completed three sessions in which they were administered one of three rTMS conditions (left M1, supplementary motor area [SMA], sham) at 1 Hz for 15 minutes. Movement-related cortical potentials (MRCPs) were assessed before and after rTMS. rTMS to the SMA was associated with a gradient increase to the early component of MRCPs, whereas rTMS to left M1 produced a stronger gradient in the late component. rTMS appears to improve movement-related electrophysiologic activity in ASD, perhaps through an influence on cortical inhibitory processes.
Publisher: Springer Science and Business Media LLC
Date: 31-10-2016
DOI: 10.1007/S10803-015-2639-7
Abstract: The medial prefrontal cortex (mPFC) and the right temporo-parietal junction (rTPj) are highly involved in social understanding, a core area of impairment in autism spectrum disorder (ASD). We used fMRI to investigate sex differences in the neural correlates of social understanding in 27 high-functioning adults with ASD and 23 matched controls. There were no differences in neural activity in the mPFC or rTPj between groups during social processing. Whole brain analysis revealed decreased activity in the posterior superior temporal sulcus in males with ASD compared to control males while processing social information. This pattern was not observed in the female sub-s le. The current study indicates that sex mediates the neurobiology of ASD, particularly with respect to processing social information.
Publisher: Springer Science and Business Media LLC
Date: 12-01-2017
DOI: 10.1007/S10803-016-3019-7
Abstract: Handwriting is commonly identified as an area of weakness in children with autism spectrum disorder (ASD), but precise deficits have not been fully characterised. Boys with ASD (n = 23) and matched controls (n = 20) aged 8-12 years completed a simple, digitised task to objectively assess handwriting performance using advanced descriptive measures. Moderate to large associations were identified between handwriting performance and attention, ASD symptoms and motor proficiency. The ASD group demonstrated significantly less smooth movements and significantly greater sizing variability and peak velocity relative to controls. These findings provide a clearer indication of the specific nature of handwriting impairments in children with ASD, and suggest a relationship with core clinical symptom severity, attention and motor behaviours.
Publisher: Springer Science and Business Media LLC
Date: 22-10-2015
DOI: 10.1007/S10803-014-2289-1
Abstract: The present study examined the presentation of autistic traits in a large adult population s le (n = 2,343). Cluster analysis indicated two subgroups with clearly distinguishable trait profiles. One group (n = 1,059) reported greater social difficulties and lower detail orientation, while the second group (n = 1,284) reported lesser social difficulties and greater detail orientation. We also report a three-factor solution for the autism-spectrum quotient, with two, related, social-themed factors (Sociability and Mentalising) and a third non-social factor that varied independently (Detail Orientation). These results indicate that different profiles of autistic characteristics tend to occur in the adult nonclinical population. Research into nonclinical variance in autistic features may benefit by considering social- and detail-related trait domains independently.
Publisher: Elsevier BV
Date: 08-2022
Publisher: Springer Science and Business Media LLC
Date: 21-02-2018
DOI: 10.1007/S10803-018-3503-3
Abstract: Deficits in cognitive flexibility are thought to underpin the core symptom of repetitive and restricted patterns of behaviour in autism spectrum disorder (ASD). Studies investigating this relationship, however, report inconsistent results. This is partly due to the variable nature of measures used to assess the construct of flexibility. The main purpose of this study was to investigate whether ASD traits differentially predict cognitive flexibility performance on lab-based neurocognitive measures relative to behavioural self-reports in a non-clinical s le of young adults. Our results indicate that ASD traits exclusively predict performance on behavioural self-reports of cognitive flexibility. These findings highlight the possibility that behavioural self-reports are a better index than lab-based neurocognitive measures to capture cognitive flexibility impairments in in iduals with ASD.
Publisher: CRC Press
Date: 25-09-2017
Publisher: Elsevier BV
Date: 07-2008
DOI: 10.1016/J.SCHRES.2008.04.001
Abstract: Impairments in social cognitive functioning are well documented in schizophrenia, however the neural basis of these deficits is unclear. A recent explanatory model of social cognition centers upon the activity of mirror neurons, which are cortical brain cells that become active during both the performance and observation of behavior. Here, we test for the first time whether mirror neuron functioning is reduced in schizophrenia. Fifteen in iduals with schizophrenia or schizoaffective disorder and fifteen healthy controls completed a transcranial magnetic stimulation (TMS) experiment designed to assess mirror neuron activation. While patients demonstrated no abnormalities in cortical excitability, motor facilitation during action observation, putatively reflecting mirror neuron activity, was reduced in schizophrenia. Dysfunction within the mirror neuron system may contribute to the pathophysiology of schizophrenia.
Publisher: Elsevier BV
Date: 04-2016
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2016.01.033
Abstract: Recent neuroimaging studies have demonstrated that activation of the putative human mirror neuron system (MNS) can be elicited via visuomotor training. This is generally interpreted as supporting an associative learning account of the mirror neuron system (MNS) that argues against the ontogeny of the MNS to be an evolutionary adaptation for social cognition. The current study assessed whether a central component of social cognition, emotion processing, would influence the MNS activity to trained visuomotor associations, which could support a broader role of the MNS in social cognition. Using functional magnetic resonance imaging (fMRI), we assessed repetition suppression to the presentation of stimulus pairs involving a simple hand action and a geometric shape that was either congruent or incongruent with earlier association training. Each pair was preceded by an image of positive, negative, or neutral emotionality. In support of an associative learning account of the MNS, repetition suppression was greater for trained pairs compared with untrained pairs in several regions, primarily supplementary motor area (SMA) and right inferior frontal gyrus (rIFG). This response, however, was not modulated by the valence of the emotional images. These findings argue against a fundamental role of emotion processing in the mirror neuron response, and are inconsistent with theoretical accounts linking mirror neurons to social cognition.
Publisher: Elsevier BV
Date: 03-2010
DOI: 10.1016/J.NEUBIOREV.2009.10.007
Abstract: This paper reviews the current literature on "empathy for pain", the ability to understand pain observed in another person, in the context of a newly documented form of pain empathy "synaesthesia for pain". In synaesthesia for pain a person not only empathises with another's pain but experiences the observed or imagined pain as if it was their own. Neural mechanisms potentially involved in synaesthesia for pain include "mirror systems": neural systems active both when observing an action, or experiencing an emotion or sensation and when executing the same action, or personally experiencing the same emotion or sensation. For ex le, we may know that someone is in pain in part because observation activates similar neural networks as if we were experiencing that pain ourselves. We propose that synaesthesia for pain may be the result of painful and/or traumatic experiences causing disinhibition in the mirror system underlying empathy for pain. We will discuss this theory in the context of a documented group of utees who experience synaesthesia for pain in phantom limbs.
Publisher: Wiley
Date: 12-2021
DOI: 10.1002/AUR.2443
Publisher: Frontiers Media SA
Date: 2013
Publisher: Springer Science and Business Media LLC
Date: 18-09-2011
DOI: 10.1007/S10803-010-1101-0
Abstract: Key theories of autism implicate orbitofrontal cortex (OFC) compromise, while olfactory identification (OI) deficits are associated with OFC dysfunction. This study aimed to complete a 5-year follow-up of children with high-functioning autism (HFA) who previously lacked the normal age-OI association and compare unirhinal-OI in children with HFA, Asperger's disorder (ASP), and controls. While both HFA and controls had improved birhinal-OI at follow-up, reduced OI in some HFA participants suggested OFC deterioration and heterogeneous OFC development. Unirhinal-OI was impaired in HFA but not ASP relative to controls, suggesting orbitofrontal compromise in HFA but integrity in ASP. Differing IQ-OI relationships existed between HFA and ASP. Findings support the hypothesis of separate neurobiological underpinnings in ASP and HFA, specifically differential orbitofrontal functioning.
Publisher: Wiley
Date: 04-2006
Publisher: Elsevier BV
Date: 07-2010
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2010.05.014
Abstract: Putative measures of mirror neuron activity suggest that mirror neurons respond preferentially to biological motion, but it remains unclear whether enhanced cortical activity occurs during the observation of any behaviour, or whether that behaviour needs to be associated with a particular object or goal. Forty-three healthy adults completed a transcranial magnetic stimulation (TMS) experiment that assessed corticospinal excitability while viewing intransitive and transitive hand gestures (compared with the presentation of a static hand). Visual presentations were designed to control for motoric and stimulus properties. A significant increase in corticospinal excitability (putatively reflecting mirror neuron activation) was seen only during the observation of transitive behaviour. These findings are consistent with the notion that human hand-related mirror neurons are sensitive to object- and goal-directed behaviour, rather than biological motion per se.
Publisher: SAGE Publications
Date: 04-12-2014
Abstract: This study aimed to investigate the integrity of on-line control of reaching in congenital spastic hemiplegia in light of disparate evidence. Twelve children with and without spastic hemiplegia (11-17 years old) completed a double-step reaching task requiring them to reach and touch a target that remained stationary for most trials (viz nonjump trial) but unexpectedly displaced laterally at movement onset for a minority of trials (20%: known as jump trials). Although children with spastic hemiplegia were generally slower than age-matched controls, they could account for target perturbation at age-appropriate levels shown by a lack of interaction effect on movement time and nonsignificant group difference for time to reach trajectory correction on jump trials. Our data suggest that at a group level, on-line control of reaching may be age-appropriate in spastic hemiplegia. However, our data also highlight the need to experimentally acknowledge the considerable heterogeneity of the spastic hemiplegia population when investigating motor cognition.
Publisher: Springer Science and Business Media LLC
Date: 17-05-2016
DOI: 10.1007/S12311-016-0788-7
Abstract: The cerebellum appears to play a key role in the development of internal rules that allow fast, predictive adjustments to novel stimuli. This is crucial for adaptive motor processes, such as those involved in walking, where cerebellar dysfunction has been found to increase variability in gait parameters. Motor adaptation is a process that results in a progressive reduction in errors as movements are adjusted to meet demands, and within the cerebellum, this seems to be localised primarily within the right hemisphere. To examine the role of the right cerebellar hemisphere in adaptive gait, cathodal transcranial direct current stimulation (tDCS) was administered to the right cerebellar hemisphere of 14 healthy adults in a randomised, double-blind, crossover study. Adaptation to a series of distinct spatial and temporal templates was assessed across tDCS condition via a pressure-sensitive gait mat (ProtoKinetics Zeno walkway), on which participants walked with an induced 'limp' at a non-preferred pace. Variability was assessed across key spatial-temporal gait parameters. It was hypothesised that cathodal tDCS to the right cerebellar hemisphere would disrupt adaptation to the templates, reflected in a failure to reduce variability following stimulation. In partial support, adaptation was disrupted following tDCS on one of the four spatial-temporal templates used. However, there was no evidence for general effects on either the spatial or temporal domain. This suggests, under specific conditions, a coupling of spatial and temporal processing in the right cerebellar hemisphere and highlights the potential importance of task complexity in cerebellar function.
Publisher: Elsevier BV
Date: 05-2011
DOI: 10.1016/J.BRAINRESBULL.2011.03.018
Abstract: The observation of other's behaviour results in increased corticospinal excitability (CSE) within the primary motor cortex, a phenomenon that has typically been interpreted in the context of motor resonance and human "mirror systems". Mirror systems are implicated in empathy, and may therefore show a preferential response to the observation of interactive behaviour. Participants were administered transcranial magnetic stimulation (TMS) to the primary motor cortex while viewing matched hand movements with or without (1) an interactive context and (2) an interactive context with an implied heightened emotional aspect. CSE was not enhanced when viewing interactive (compared with in idual) hand movements. There was, however, some evidence for an enhanced response when viewing hand movements with an emotional component. There was no association between mirror systems and self-reported empathy. Mirror systems may not be more responsive to interactive behaviour, but the inclusion of a strong emotional element could be of significance to mirror neurons.
Publisher: Wiley
Date: 18-09-2006
Publisher: Elsevier BV
Date: 10-2015
DOI: 10.1016/J.RIDD.2015.07.027
Abstract: Recent evidence indicates that the ability to correct reaching movements in response to unexpected target changes (i.e., online control) is reduced in children with developmental coordination disorder (DCD). Recent computational modeling of human reaching suggests that these inefficiencies may result from difficulties generating and/or monitoring internal representations of movement. This study was the first to test this putative relationship empirically. We did so by investigating the degree to which the capacity to correct reaching mid-flight could be predicted by motor imagery (MI) proficiency in a s le of children with probable DCD (pDCD). Thirty-four children aged 8 to 12 years (17 children with pDCD and 17 age-matched controls) completed the hand rotation task, a well-validated measure of MI, and a double-step reaching task (DSRT), a protocol commonly adopted to infer one's capacity for correcting reaching online. As per previous research, children with pDCD demonstrated inefficiencies in their ability to generate internal action representations and correct their reaching online, demonstrated by inefficient hand rotation performance and slower correction to the reach trajectory following unexpected target perturbation during the DSRT compared to age-matched controls. Critically, hierarchical moderating regression demonstrated that even after general reaching ability was controlled for, MI efficiency was a significant predictor of reaching correction efficiency, a relationship that was constant across groups. Ours is the first study to provide direct pilot evidence in support of the view that a decreased capacity for online control of reaching typical of DCD may be associated with inefficiencies generating and/or using internal representations of action.
Publisher: Elsevier BV
Date: 07-2013
DOI: 10.1016/J.BBR.2013.04.027
Abstract: Research indicates that mirror neurons are important for social cognition, including emotion processing. Emerging evidence, however, also reveals that emotional stimuli might be capable of modulating human mirror neuron system (MNS) activity. The current study used transcranial magnetic stimulation (TMS) to assess putative mirror neuron function following emotionally evocative images in twenty healthy adults. Participants observed videos of either a transitive hand action or a static hand while undergoing TMS of the primary motor cortex. In order to examine the effect of emotion on the MNS, each video was preceded by an image of either a positive, negative or neutral valence. MNS activity was found to be augmented by both the positive and negative (relative to neutral) stimuli, thus providing empirical support for a bi-directional link between emotion and the MNS, whereby both positively and negatively valenced stimuli are capable of facilitating mirror neuron activity. The potential adaptive significance of this finding is discussed.
Publisher: Elsevier BV
Date: 09-2007
DOI: 10.1016/J.JNEUMETH.2007.06.002
Abstract: Various methods of application of repetitive transcranial magnetic stimulation (TMS) have been evaluated for their potential capacity to alter motor cortical excitability. Initial research suggests that the repetitive application of paired TMS pulses (repetitive paired pulse TMS (rppTMS)) may have greater effects on cortical excitability, perhaps through the facilitation of I-wave interaction. We aimed to compare the post-train effects of 15 min trains of rppTMS to investigate the potential therapeutic application of this technique as well as to compare it to a standard high frequency repetitive TMS paradigm. Ten normal subjects received three 15 min sessions of rppTMS, 5 Hz high frequency rTMS and sham TMS in randomised order. rppTMS consisted of a single train of 180 pulse pairs (0.2 Hz, 1.5 ms inter-stimulus interval, supra-threshold intensity) administered over 15 min. The rTMS condition involved 750 pulses provided in 5s 5 Hz trains with a 25s inter-train interval at 90% of the RMT. Motor evoked potential size and cortical silent period duration were assessed before and after each session. There were no significant changes in cortical excitability produced by any of the stimulation conditions. Five hertz rTMS produced an increase in cortical silent period duration (p=0.004) which was not affected by rppTMS. Fifteen minutes trains of 1.5ms rppTMS do not substantially increase post train cortical excitability. Repetitive brief trains of 5Hz rTMS also do not alter excitability but appear to effect cortical inhibition.
Publisher: Elsevier BV
Date: 11-2014
DOI: 10.1016/J.RIDD.2014.07.042
Abstract: The present study aimed to provide preliminary insight into the integrity of motor imagery (MI) in adults with probable developmental coordination disorder (pDCD). Based on a strong body of evidence indicating that paediatric s les of DCD often experience difficulties engaging MI, we hypothesised that young adults with pDCD would demonstrate similar difficulties. The performance of 12 young adults (19-35 years) with pDCD was compared to 47 age-matched controls on a traditional mental hand rotation task. Mean inverse efficiency scores were generated for each participant by iding each participant's mean RT by their proportion of correct responses at each of the stimuli presentation conditions. Preliminary analysis revealed that the performance profiles of in iduals with pDCD and age-matched controls showed evidence of being constrained by the biomechanical and postural constraints of real movement, suggesting that both groups engaged in an embodied (MI) strategy to complete the task. Despite engaging in a MI strategy, however, young adults with pDCD were nonetheless significantly less efficient when doing so, shown by significant main effects for group on all group efficiency comparisons. Based on the assumption that MI provides insight into the internal 'neural' action representation that precedes action, we argue that the less efficient MI performance demonstrated by young adults with pDCD may indicate inefficiencies engaging or implementing internal action representations. Implications and directions for future research are discussed.
Publisher: Elsevier BV
Date: 02-2012
DOI: 10.1016/J.NEULET.2011.12.018
Abstract: Mirror neurons are thought to facilitate emotion processing, but it is unclear whether the valence of an emotional presentation (positive or negative) can influence subsequent mirror neuron activity. Participants completed a transcranial magnetic stimulation experiment that involved stimulation of the primary motor cortex, and electromyography recording from contralateral hand muscles. This was performed while participants viewed videos of either a static hand or a transitive hand action preceded by either a positive or negative stimulus. Corticospinal excitability facilitation during action observation was significantly greater following the presentation of negative (relative to positive) stimuli this was evident for the first dorsal interosseous muscle (which was central to the observed grasp), but not for the abductor digiti minimi muscle. This study provides evidence that emotional valence can modulate mirror neuron activity, which may reflect an adaptive mechanism.
Publisher: Elsevier BV
Date: 10-2010
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2010.07.029
Abstract: Synaesthesia for pain is a phenomenon where a person experiences pain when observing or imagining another in pain. Anecdotal reports of this type of experience have most commonly occurred in in iduals who have lost a limb. Distinct from phantom pain, synaesthesia for pain is triggered specifically in response to pain in another. Here, we provide the first preliminary investigation into synaesthesia for pain in utees to determine the incidence and characteristics of this intriguing phenomenon. Self-referring utees (n=74) answered questions on synaesthesia for pain within a broader survey of phantom pain. Of the participants, 16.2% reported that observing or imagining pain in another person triggers their phantom pain. Further understanding of synaesthesia for pain may provide a greater insight to abnormal empathic function in clinical populations as well as therapeutic intervention for at risk groups.
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.BRS.2019.02.013
Abstract: The prefrontal cortex regulates behavioural adaptation in response to feedback. However, the causal role of different prefrontal regions remains unclear, based on indirect evidence derived from functional neuroimaging. Neuroimaging studies show dorsomedial prefrontal activation during feedback monitoring, whereas the ventrolateral prefrontal cortex engages during behavioural adaptation (shifting). We used high-definition transcranial direct current stimulation (HD-tDCS) to elucidate the roles of the ventrolateral prefrontal cortex (vlPFC) and the dorsomedial prefrontal cortex (dmPFC) in behaviour change, using a probabilistic reversal learning task (PRLT). Fifty-two healthy adults were randomly assigned to receive cathodal HD-tDCS to inhibit the vlPFC or the dmPFC versus sham stimulation, prior to completing the PRLT. The outcome measures were the number of perseverative errors and the electroencephalography (EEG) signals of feedback-related negativity (FRN) in the PRLT. We hypothesised that inhibition of the vlPFC would be specifically associated with more perseverative errors and weaker FRNs. We found that vlPFC inhibition was associated with higher perseverative errors compared to sham and dmPFC stimulation conditions. Although there were no statistically significant differences in FRN litudes, the effect sizes indicate an association between inhibition of the vlPFC and lower FRN litudes. Our findings support a causal role of the vlPFC on feedback-based behavioural adaptation, which is critical for adaptive goal-driven behaviour.
Publisher: Cold Spring Harbor Laboratory
Date: 08-01-2021
DOI: 10.1101/2021.01.06.425653
Abstract: There is evidence to suggest a disruption of gamma-aminobutyric acid (GABA) in autism spectrum disorder (ASD), but findings are mixed. Concurrent electroencephalography and transcranial magnetic stimulation (TMS-EEG) provides a novel method by which to probe GABA-mediated cortical inhibition. With a particular focus on GABAB-ergic mechanisms, we investigated the N100 peak of the TMS evoked potential (TEP), as well as long interval cortical inhibition (LICI EEG ) in adults with ASD (n = 23 12 female) without intellectual disability, and a neurotypical comparison group (n =22 12 female) matched for age, sex, and IQ. Seventy-five single-(spTMS) and 75 paired-(ppTMS 100 ms inter-stimulus-interval) pulses were applied to the right primary motor cortex (M1), right temporoparietal junction (TPJ), and right dorsolateral prefrontal cortex (DLPFC) while EEG was recorded from 20 scalp electrodes. Additionally, electromyography (EMG) was used to investigate corticospinal inhibition following ppTMS to M1 (LICI EMG ). There were no group differences in the N100 litude or latency following spTMS. LICI outcomes following ppTMS, as measured by either EEG or EMG, also did not differ between groups. These findings were further supported by Bayesian analyses, which provided weak-moderate support for the null hypothesis. Data presented here reflect adults without intellectual disability, and the generalisability of these results is therefore limited. The findings of this study argue against GABAB-ergic impairment in adults with ASD without intellectual disability, at least at the cortical regions examined. Further research investigating these mechanisms in ASD at various ages, with varying degrees of symptomatology, and at different brain sites is an important factor in understating the role of GABA in the neuropathophysiology of ASD.
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.NEUROPHARM.2012.06.017
Abstract: Mounting evidence suggests a possible role for γ-aminobutyric acid (GABA) in the neuropathophysiology of autism spectrum disorders (ASD), but the extent of this impairment is unclear. A non-invasive, in vivo measure of GABA involves transcranial magnetic stimulation (TMS) of the primary motor cortex to probe cortical inhibition. In iduals diagnosed with ASD (high-functioning autism or Asperger's disorder) (n = 36 [28 male] mean age: 26.00 years) and a group of healthy in iduals (n = 34 [23 male] mean age: 26.21 years) (matched for age, gender, and cognitive function) were administered motor cortical TMS paradigms putatively measuring activity at GABAA and GABAB receptors (i.e., short and long interval paired pulse TMS, cortical silent period). All cortical inhibition paradigms yielded no difference between ASD and control groups. There was, however, evidence for short interval cortical inhibition (SICI) deficits among those ASD participants who had experienced early language delay, suggesting that GABA may be implicated in an ASD subtype. The current findings do not support a broad role for GABA in the neuropathophysiology of ASD, but provide further indication that GABAA could be involved in ASD where there is a delay in language acquisition. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.
Publisher: Elsevier BV
Date: 06-2012
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2012.03.016
Abstract: Interpersonal motor resonance (IMR) is presumed to result from activity within the human mirror neuron system, which itself is thought to comprise the inferior parietal lobule (IPL) and inferior frontal gyrus (IFG). Twenty healthy adults underwent anodal, cathodal, and sham transcranial direct current stimulation (tDCS) to either IPL or IFG immediately before the assessment of IMR (using transcranial magnetic stimulation). IMR (i.e., motor-evoked potential litude during transitive action observation relative to static observation) was significantly reduced following both anodal and cathodal stimulation of IFG (relative to sham), but there was no effect of stimulation for IPL. These data support the role of IFG, a presumed mirror neuron region, in IMR.
Publisher: Elsevier BV
Date: 08-2013
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2013.06.020
Abstract: Recent research has begun to investigate sensory processing in relation to nonclinical variation in traits associated with the autism spectrum disorders (ASD). We propose that existing accounts of autistic perception can be augmented by considering a role for in idual differences in top-down expectations for the precision of sensory input, related to the processing of state-dependent levels of uncertainty. We therefore examined ASD-like traits in relation to the rubber-hand illusion: an experimental paradigm that typically elicits crossmodal integration of visual, tactile, and proprioceptive information in an unusual illusory context. In iduals with higher ASD-like traits showed reduced effects of the rubber-hand illusion on perceived arm position and reach-to-grasp movements, compared to in iduals with lower ASD-like traits. These differences occurred despite both groups reporting the typical subjective experience of the illusion concerning visuotactile integration and ownership for the rubber hand. Together these results suggest that the integration of proprioceptive information with cues for arm position derived from the illusory context differs between in iduals partly in relation to traits associated with ASD. We suggest that the observed differences in sensory integration can be best explained in terms of differing expectations regarding the precision of sensory estimates in contexts that suggest uncertainty.
Publisher: Elsevier BV
Date: 07-2015
DOI: 10.1016/J.PSCYCHRESNS.2015.05.003
Abstract: Abnormalities within white matter (WM) have been identified in autism spectrum disorder (ASD). Although there is some support for greater neurobiological deficits among females with ASD, there is little research investigating sex differences in WM in ASD. We used diffusion tensor imaging (DTI) to investigate WM aberration in 25 adults with high-functioning ASD and 24 age-, sex- and IQ-matched controls. Tract-based spatial statistics (TBSS) was used to explore differences in WM in major tract bundles. The effects of biological sex were also investigated. TBSS revealed no differences in fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), or axial diffusivity (AD) between groups. There were no effects of biological sex. We consider whether methodological differences between past studies have contributed to the highly heterogeneous findings in the literature. Finally, we suggest that, among a high-functioning s le of adults with ASD, differences in WM microstructure may not be related to clinical impairment.
Publisher: The Royal Society
Date: 07-03-2015
Abstract: Recent predictive processing accounts of perception and action point towards a key challenge for the nervous system in dynamically optimizing the balance between incoming sensory information and existing expectations regarding the state of the environment. Here, we report differences in the influence of the preceding sensory context on motor function, varying with respect to both clinical and subclinical features of autism spectrum disorder (ASD). Reach-to-grasp movements were recorded subsequent to an inactive period in which illusory ownership of a prosthetic limb was induced. We analysed the sub-components of reach trajectories derived using a minimum-jerk fitting procedure. Non-clinical adults low in autistic features showed disrupted movement execution following the illusion compared to a control condition. By contrast, in iduals higher in autistic features (both those with ASD and non-clinical in iduals high in autistic traits) showed reduced sensitivity to the presence of the illusion in their reaching movements while still exhibiting the typical perceptual effects of the illusion. Clinical in iduals were distinct from non-clinical in iduals scoring high in autistic features, however, in the early stages of movement. These results suggest that the influence of high-level representations of the environment differs between in iduals, contributing to clinical and subclinical differences in motor performance that manifest in a contextual manner. As high-level representations of context help to explain fluctuations in sensory input over relatively longer time scales, more circumscribed sensitivity to prior or contextual information in autistic sensory processing could contribute more generally to reduced social comprehension, sensory impairments and a stronger desire for predictability and routine.
Publisher: Elsevier BV
Date: 11-2012
DOI: 10.1016/J.NEULET.2012.09.036
Abstract: 'Mirror pain' describes when the observation of another's pain experience induces a personal experience of pain. It has been suggested that mirror pain could result from changes in neural excitability or inhibition. In this study we used transcranial magnetic stimulation (TMS) to investigate motor cortical excitability in lower-limb utees who experience mirror pain. Using paired-pulse TMS to assess motor cortical inhibition (CI) and cortical facilitation (CF), recordings were taken from the right first dorsal interosseus in lower-limb utees who experience mirror pain (MP+), lower-limb utees who do not experience mirror pain (MP-), and non- utee controls. No differences in CI or CF were observed between the MP+ and both control groups. Thus, when not paired with a pain-related stimulus, changes in motor cortical excitability do not appear to contribute to the experience of mirror pain in lower-limb utees.
Publisher: Springer Science and Business Media LLC
Date: 23-03-2013
DOI: 10.1007/S10803-013-1811-1
Abstract: This paper reviews the literature exploring gender differences associated with the clinical presentation of autism spectrum disorders (ASD). The potentially mediating effect of comorbid psychopathology, biological and neurodevelopmental implications on these gender differences is also discussed. A vastly heterogeneous condition, while females on the lower-functioning end of the spectrum appear to be more severely affected, an altered clinical manifestation of the disorder among high-functioning females may consequently result in many being un- or mis-diagnosed. To date, there is strong bias in the literature towards the clinical presentation of ASD in males. It is imperative that future research explores gender differences across the autism spectrum, in order to improve researchers', clinicians' and the public's understanding of this debilitating disorder.
Publisher: Elsevier BV
Date: 03-2014
DOI: 10.1016/J.BRS.2013.10.004
Abstract: Biomedical treatment options for autism spectrum disorder (ASD) are extremely limited. Repetitive transcranial magnetic stimulation (rTMS) is a safe and efficacious technique when targeting specific areas of cortical dysfunction in major depressive disorder, and a similar approach could yield therapeutic benefits in ASD, if applied to relevant cortical regions. The aim of this study was to examine whether deep rTMS to bilateral dorsomedial prefrontal cortex improves social relating in ASD. 28 adults diagnosed with either autistic disorder (high-functioning) or Asperger's disorder completed a prospective, double-blind, randomized, placebo-controlled design with 2 weeks of daily weekday treatment. This involved deep rTMS to bilateral dorsomedial prefrontal cortex (5 Hz, 10-s train duration, 20-s inter-train interval) for 15 min (1500 pulses per session) using a HAUT-Coil. The sham rTMS coil was encased in the same helmet of the active deep rTMS coil, but no effective field was delivered into the brain. Assessments were conducted before, after, and one month following treatment. Participants in the active condition showed a near significant reduction in self-reported social relating symptoms from pre-treatment to one month follow-up, and a significant reduction in social relating symptoms (relative to sham participants) for both post-treatment assessments. Those in the active condition also showed a reduction in self-oriented anxiety during difficult and emotional social situations from pre-treatment to one month follow-up. There were no changes for those in the sham condition. Deep rTMS to bilateral dorsomedial prefrontal cortex yielded a reduction in social relating impairment and socially-related anxiety. Further research in this area should employ extended rTMS protocols that approximate those used in depression in an attempt to replicate and lify the clinical response.
Publisher: Elsevier
Date: 2018
Publisher: Informa UK Limited
Date: 22-01-2008
DOI: 10.1080/13803390701290055
Abstract: There is evidence for reduced cognitive inhibitory control in schizophrenia, but associated behavioral consequences are unclear. In an investigation of the link between cognitive inhibition and impulsive behavior, violent offenders with schizophrenia (n=18) and healthy adults completed spatial Stroop and negative priming tasks and the Barratt Impulsiveness Scale (a self-report impulsivity measure). Negative priming (but not Stroop) was impaired among violent offenders with schizophrenia, but there was no association between reduced inhibition and impulsivity. While these findings should be interpreted with caution, cognitive inhibition in schizophrenia may be unrelated to impulsive behaviors that are commonly linked to violent offending.
Publisher: Elsevier BV
Date: 05-2017
Publisher: Wiley
Date: 10-04-2018
DOI: 10.1002/EJP.1213
Abstract: Fibromyalgia is a complex chronic disorder with few effective treatments currently available. One promising treatment option is repetitive transcranial magnetic stimulation (rTMS), a non-invasive brain stimulation technique that has shown promise in disorders effecting the central nervous system. We assessed the efficacy of a course of high-frequency (10 Hz) left-hemisphere dorsolateral prefrontal cortex (DLPFC) rTMS in 26 patients (14 active 12 sham) with a diagnosis of fibromyalgia. Participants underwent a double-blind stimulation protocol of daily (Monday-Friday) rTMS sessions over four consecutive weeks (total of 20 sessions 75 × 4-s 10 Hz trains at 120% resting motor threshold). Assessments were conducted at baseline, 4 weeks and at 1-month follow-up. Using mixed-model analysis we did not identify a group difference for our primary outcome measures. However, we found that patients in the active group compared to sham treatment group had significantly greater improvement in the Physical Fatigue (p = 0.045) and General Fatigue (p = 0.023) scales of the Multidimensional Fatigue Inventory-20 at the 1 month follow-up. In a responder analysis, we also found the active group was significantly more likely (2.84 times) to achieve a minimum 30% improvement in pain intensity ratings. (p = 0.024). High-frequency rTMS applied daily for 4 weeks to the left DLPFC induces significant relief from fatigue and a greater chance of clinically meaningful improvement in pain intensity in patients with fibromyalgia. These results suggest DLPFC rTMS may be a relevant therapy for fibromyalgia. This study provides evidence that 4-weeks of daily rTMS to the left DLPFC is able to improve fatigue in fibromyalgia. This novel finding provides impetus for the further investigation of the utility of TMS approaches for the relief of fatigue, an otherwise difficult-to-treat symptom, in fibromyalgia and related disorders.
Publisher: Elsevier BV
Date: 09-2020
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.NEUROPSYCHOLOGIA.2014.02.018
Abstract: The adaptation account of mirror neurons in humans proposes that mirror systems have been selected for in evolution to facilitate social cognition. By contrast, a recent "association" account of mirror neurons in humans argues that mirror systems are not the result of a specific adaptation, but of sensorimotor learning arising from concurrent visual and motor activity. Here, we used transcranial magnetic stimulation (TMS) and electromyography (EMG) to evaluate whether visuomotor associations affect interpersonal motor resonance, a putative measure of mirror system activity. 18 participants underwent two TMS sessions exploring whether visuomotor associations established throughout one׳s lifespan, namely common movements and movements generated from one׳s own perspective, are associated with increased putative mirror system activity. Our results showed no overall difference in interpersonal motor resonance to common versus uncommon actions, or actions presented from an egocentric (self) versus an allocentric (other) perspective. We did, however, observe increased interpersonal motor resonance within the abductor digiti minimi (ADM) muscle in response to allocentric compared to egocentric movements. As the association model predicts stronger mirror system response to actions with stronger visuomotor associations, such as common movements and those presented from an egocentric perspective, our findings provide little evidence to support the association model.
Publisher: Cambridge University Press (CUP)
Date: 03-03-2012
DOI: 10.1016/J.EURPSY.2012.02.006
Abstract: Deep transcranial magnetic stimulation (TMS) is a technique of neuromodulation and neurostimulation based on the principle of electromagnetic induction of an electric field in the brain. The coil (H-coil) used in deep TMS is able to modulate cortical excitability up to a maximum depth of 6 cm and is therefore able not only to modulate the activity of the cerebral cortex but also the activity of deeper neural circuits. Deep TMS is largely used for the treatment of drug-resistant major depressive disorder (MDD) and is being tested to treat a very wide range of neurological, psychiatric and medical conditions. The aim of this review is to illustrate the biophysical principles of deep TMS, to explain the pathophysiological basis for its utilization in each psychiatric disorder (major depression, autism, bipolar depression, auditory hallucinations, negative symptoms of schizophrenia), to summarize the results presented thus far in the international scientific literature regarding the use of deep TMS in psychiatry, its side effects and its effects on cognitive functions.
Publisher: Wiley
Date: 27-09-2018
DOI: 10.1111/EJN.13675
Abstract: The temporoparietal junction (TPJ) is implicated in mental and emotional state attribution, processes associated with autism-relevant traits. Transcranial direct current stimulation (tDCS) to the TPJ can influence social-cognitive performance. However, associations with electrophysiology and autism-relevant traits remain relatively unexamined. This study had two aims: first, exploring links between Autism-Spectrum Quotient (AQ) scores and social-cognitive performance second, examining interactions between AQ scores and high-definition-tDCS (HD-tDCS) applied to the right TPJ in terms of mental/emotional state attribution and neurophysiological outcomes. Fifty-three participants completed mental/emotional state attribution tasks before and after HD-tDCS. Pre-stimulation mental state attribution accuracy was reduced in participants with higher AQ Switching scores. Cathodal stimulation was associated with reduced emotion attribution performance in participants with higher AQ Switching and AQ Social scores (the latter at trend-level). Anodal stimulation more frequently interacted with AQ Social scores in terms of neurophysiology, in particular regarding reduced delta power in the left compared to right TPJ, and trend-level positive interactions with P100 and P300 latencies during the emotion recognition task. Elements of attention/switching (AQ Switching) may subserve or underpin elements of social cognition (AQ Social), and cathodal and anodal stimulation may have differing effects depending on trait levels in these domains. This study makes an important and original contribution in terms of increasing understanding of how such trait-level variation might interact with the effects of tDCS and also extending previous studies with regard to understanding potential roles of the rTPJ in both attention and social cognition and how autism-relevant traits might influence TPJ function.
Publisher: Public Library of Science (PLoS)
Date: 12-06-2014
Publisher: Wiley
Date: 12-05-2017
DOI: 10.1111/PSYP.12888
Abstract: This study compared the performance of a low-cost wireless EEG system to a research-grade EEG system on an auditory oddball task designed to elicit N200 and P300 ERP components. Participants were 15 healthy adults (6 female) aged between 19 and 40 (M = 28.56 SD = 6.38). An auditory oddball task was presented comprising 1,200 presentations of a standard tone interspersed by 300 trials comprising a deviant tone. EEG was simultaneously recorded from a modified Emotiv EPOC and a NeuroScan SynAmps RT EEG system. The modifications made to the Emotiv system included attaching research grade electrodes to the Bluetooth transmitter. Additional modifications enabled the Emotiv system to connect to a portable impedance meter. The cost of these modifications and portable impedance meter approached the purchase value of the Emotiv system. Preliminary analyses revealed significantly more trials were rejected from data acquired by the modified Emotiv compared to the SynAmps system. However, the ERP waveforms captured by the Emotiv system were found to be highly similar to the corresponding waveform from the SynAmps system. The latency and peak litude of N200 and P300 components were also found to be similar between systems. Overall, the results indicate that, in the context of an oddball task, the ERP acquired by a low-cost wireless EEG system can be of comparable quality to research-grade EEG acquisition equipment.
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.NEURON.2019.01.004
Abstract: Neuroethics is central to the Australian Brain Initiative's aim to sustain a thriving and responsible neurotechnology industry. Diverse and inclusive community and stakeholder engagement and a trans-disciplinary approach to neuroethics will be key to the success of the Australian Brain Initiative.
Publisher: Informa UK Limited
Date: 11-2013
DOI: 10.1080/13546805.2012.758878
Abstract: This paper reviews the literature as it relates to perceptual processes in body dysmorphic disorder (BDD). A narrative-style review of the literature was undertaken to explore the relationship between BDD and obsessive-compulsive disorder, the empirical evidence for aberrant own-body perception in BDD, and the possible role of the parietal cortex in the disorder. The extant literature appears to support the postulation that BDD is underpinned by a dysfunction in somatoperception-the process by which in iduals formulate a sense of what they look like. Investigation of somatoperceptive processes in BDD and related brain structures would provide important insight about the development and maintenance of this complex and often neglected psychiatric condition, and, in turn, help improve its treatment.
Publisher: Psychology Press
Date: 14-04-0384
Publisher: Elsevier BV
Date: 07-2013
DOI: 10.1016/J.CORTEX.2012.08.019
Abstract: Apart from tics, echopraxia or echophenomena (EP), i.e., automatic imitation of observed movements, are common in patients with Gilles de la Tourette syndrome (TS). The supplementary motor area (SMA) has been shown to be overactive before the onset of tics in these patients, and it is possible that this area might also play a key role in the generation of echopraxia. We wondered whether EP can also be evoked in healthy controls (HC) by modifying neural activity of this cortical region. To this end, we modulated activity of the SMA in 30 HC by repetitive transcranial magnetic stimulation (rTMS) in an attempt to induce EP. We used both 5 Hz (which can temporarily increase neural activity) and 1 Hz (which disrupts or reduces cortical activity) rTMS. Video clips were presented to 30 HC before and after stimulation. Each clip showed one single movement, either a tic of a TS patient or a spontaneous movement of a HC. During the whole presentation, participants were videotaped in order to detect EP. Video films of participants' responses were rated by two independent raters with respect to EP frequency. Our results reveal an increase of EP following 5 Hz stimulation but no effect following 1 Hz stimulation. This finding implies that the SMA is a relay mediating EP.
Publisher: Elsevier BV
Date: 2020
Publisher: Wiley
Date: 08-07-2010
DOI: 10.1111/J.1469-8749.2010.03665.X
Abstract: Controversy surrounds the distinction between high-functioning autism (HFA) and Asperger disorder, but motor abnormalities are associated features of both conditions. This study examined motor cortical inhibition and excitability in HFA and Asperger disorder using transcranial magnetic stimulation (TMS). Participants were diagnosed by experienced clinicians strictly according to DSM-IV criteria. Participants with HFA (nine males, two females mean age 16y 8mo, SD 4y 5mo) or Asperger disorder (11 males, three females mean age 19y 1mo, SD 4y 2mo) and neurotypical participants (eight males, three females mean age 19y 0mo, SD 3y 1mo) were administered a paired-pulse TMS paradigm intended to assess motor cortical inhibition and excitability. Responses to TMS were recorded by electromyography. Cortical inhibition was significantly reduced in the HFA group compared with both the Asperger disorder (p<0.001) and neurotypical (p<0.001) groups, suggesting disruption of activity at gamma-aminobutyric acid A (GABA(A)) receptors. There was no group difference in cortical excitability. Cortical inhibition deficits may underlie motor dysfunction in autism, and perhaps even relate to specific clinical symptoms (e.g. repetitive behaviours). These findings provide novel evidence for a possible neurobiological dissociation between HFA and Asperger disorder based on GABAergic function.
Publisher: BMJ
Date: 07-2021
DOI: 10.1136/BMJOPEN-2020-046830
Abstract: There are no well-established biomedical treatments for the core symptoms of autism spectrum disorder (ASD). A small number of studies suggest that repetitive transcranial magnetic stimulation (rTMS), a non-invasive brain stimulation technique, may improve clinical and cognitive outcomes in ASD. We describe here the protocol for a funded multicentre randomised controlled clinical trial to investigate whether a course of rTMS to the right temporoparietal junction (rTPJ), which has demonstrated abnormal brain activation in ASD, can improve social communication in adolescents and young adults with ASD. This study will evaluate the safety and efficacy of a 4-week course of intermittent theta burst stimulation (iTBS, a variant of rTMS) in ASD. Participants meeting criteria for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition ASD (n=150, aged 14–40 years) will receive 20 sessions of either active iTBS (600 pulses) or sham iTBS (in which a sham coil mimics the sensation of iTBS, but no active stimulation is delivered) to the rTPJ. Participants will undergo a range of clinical, cognitive, epi/genetic, and neurophysiological assessments before and at multiple time points up to 6 months after iTBS. Safety will be assessed via a structured questionnaire and adverse event reporting. The study will be conducted from November 2020 to October 2024. The study was approved by the Human Research Ethics Committee of Monash Health (Melbourne, Australia) under Australia’s National Mutual Acceptance scheme. The trial will be conducted according to Good Clinical Practice, and findings will be written up for scholarly publication. Australian New Zealand Clinical Trials Registry (ACTRN12620000890932).
Publisher: Springer Science and Business Media LLC
Date: 02-08-2017
DOI: 10.1007/S00429-017-1484-1
Abstract: Often, during daily experiences, hearing peers' actions can activate motor regions of the CNS. This activation is termed auditory-motor resonance (AMR) and is thought to represent an internal simulation of one's motor memories. Currently, AMR is demonstrated at the neuronal level in the Macaque and songbird, in conjunction with evidence on a systems level in humans. Here, we review evidence of AMR development from a motor control perspective. In the context of internal modelling, we consider data that demonstrates sensory-guided motor learning and action maintenance, particularly the notion of sensory comparison seen during songbird vocalisation. We suggest that these comparisons generate accurate sensory-to-motor inverse mappings. Furthermore, given reports of mapping decay after songbird learning, we highlight the proposal that the maintenance of these sensorimotor maps potentially explains why frontoparietal regions are activated upon hearing known sounds (i.e., AMR). In addition, we also recommend that activation of these types of internal models outside of action execution may provide an ecological advantage when encountering known stimuli in ambiguous conditions.
Publisher: Springer Science and Business Media LLC
Date: 19-07-2016
Publisher: Wiley
Date: 07-09-2009
DOI: 10.1111/J.1469-8749.2009.03270.X
Abstract: Motor dysfunction is common to both autism and Asperger syndrome, but the underlying neurophysiological impairments are unclear. Neurophysiological examinations of motor dysfunction can provide information about likely sites of functional impairment and can contribute to the debate about whether autism and Asperger syndrome are variants of the same disorder or fundamentally distinct neurodevelopmental conditions. We investigated the neurophysiology of internally determined motor activity in autism and Asperger syndrome via examination of movement-related potentials (MRPs). We used electroencephalography to investigate MRPs, via an internally cued movement paradigm, in the following three groups: (1) in iduals with high-functioning autism (14 males, one female mean age 13 y 1 mo, SD 4 y 2 mo, range 7 y 8 mo to 20 y 9 mo mean Full-scale IQ 93.40, SD 20.72) (2) in iduals with Asperger syndrome (10 males, two females mean age 13 y 7 mo, SD 3 y 9 mo, range 8 y 11 mo to 20 y 4 mo mean Full-scale IQ 103.25, SD 19.37), and (3) a healthy control group (13 males, seven females mean age 14 y 0 mo, SD 3 y 11 mo range 8 y 4 mo to 21 y 0 mo mean Full-scale IQ 114.25, SD 11.29). Abnormal MRPs can reflect disruption of motor-related neural networks involving the basal ganglia, thalamus, and supplementary motor area. There was evidence for abnormal MRPs in autism (e.g. increased post-movement cortical activity, abnormal peak time) but not in Asperger syndrome. The results support basal ganglia, thalamus, and supplementary motor area involvement as a likely source of motor dysfunction in autism, and provide further evidence for the neurobiological separateness of autism and Asperger syndrome.
Publisher: Springer Science and Business Media LLC
Date: 28-09-2010
DOI: 10.1007/S00221-010-2369-1
Abstract: Several studies have found that response inhibition in the stop signal task is associated with a delay in subsequent response speed, which may result from the automatic retrieval of a conflicting stimulus-goal association. This study investigated the neurophysiological correlates of this sequence effect using event related potentials (ERPs). ERPs were recorded in 17 healthy people while they performed the stop signal task. We found reduced P3b litude for responses following successful inhibition, but only when the stimulus was repeated from the previous trial (repetition-after-effects). For responses following failed inhibition, P3b litude was reduced regardless of stimulus repetition status. We also found a general increase in frontal N2 litude on response trials following inhibition, regardless of stimulus repetition or behavioural slowing. The complex pattern of ERP findings, dependent on stimulus repetition and success of inhibition, suggests multiple sources of behavioural slowing in the present data. ERP findings suggest that a memory retrieval processes underlies the repetition component of inhibition after effects. These findings are considered within the broader context of ERP findings in the negative priming literature.
Publisher: Elsevier BV
Date: 03-2020
Publisher: Informa UK Limited
Date: 02-04-2016
Publisher: Oxford University Press (OUP)
Date: 26-10-2010
Publisher: Elsevier BV
Date: 03-2012
DOI: 10.1016/J.BIOPSYCH.2011.09.001
Abstract: The neurobiology of autism spectrum disorder (ASD) is not particularly well understood, and biomedical treatment approaches are therefore extremely limited. A prominent explanatory model suggests that social-relating symptoms may arise from dysfunction within the mirror neuron system, while a recent neuroimaging study suggests that these impairments in ASD might reduce with age. Participants with autism spectrum disorder (i.e., DSM-IV autistic disorder or Asperger's disorder) (n = 34) and matched control subjects (n = 36) completed a transcranial magnetic stimulation study in which corticospinal excitability was assessed during the observation of hand gestures. Regression analyses revealed that the ASD group presented with significantly reduced corticospinal excitability during the observation of a transitive hand gesture (relative to observation of a static hand) (p < .05), which indicates reduced putative mirror neuron system activity within ventral premotor cortex/inferior frontal gyrus. Among the ASD group, there was also a negative association between putative mirror neuron activity and self-reported social-relating impairments, but there was no indication that mirror neuron impairments in ASD decrease with age. These data provide general support for the mirror neuron hypothesis of autism researchers now must clarify the precise functional significance of mirror neurons to truly understand their role in the neuropathophysiology of ASD and to determine whether they should be used as targets for the treatment of ASD.
Publisher: Elsevier BV
Date: 03-2012
DOI: 10.1016/J.BBR.2011.11.037
Abstract: Neuroimaging studies suggest that the medial prefrontal cortex (mPFC) plays a central role in cognitive theory of mind (ToM). This can be assessed more definitively, however, using repetitive transcranial magnetic stimulation (rTMS). Sixteen healthy participants (10 females, 6 males) completed tasks assessing cognitive and affective ToM following low-frequency deep rTMS to bilateral mPFC in active-stimulation and placebo-stimulation sessions. There was no effect of deep rTMS on either cognitive or affective ToM performance. When examining self-reported empathy, however, there was evidence for a double dissociation: deep rTMS disrupted affective ToM performance for those with high self-reported empathy, but improved affective ToM performance for those with low self-reported empathy. mPFC appears to play a role in affective ToM processing, but the present study suggest that stimulation outcomes are dependent on baseline empathic abilities.
Publisher: Elsevier BV
Date: 08-2015
Publisher: Frontiers Media SA
Date: 13-08-2020
Start Date: 01-2013
End Date: 12-2015
Amount: $150,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2020
End Date: 12-2024
Amount: $469,871.00
Funder: Australian Research Council
View Funded Activity