Page 56 - MEGIN Book Of Abstracts - 2023

Cortical excitation-inhibition ratio mediates the were themselves correlated (p = .035). Two mediation
effect of pre-attentive auditory processing deficits models were investigated, with right MMN latency as
on interpersonal difficulties (2020) predictor and SPQ-interpersonal and AQ-communica-
tion as outcome variables. Right STC glutamate/GABA
Ford, Talitha C; Woods, Will; Enticott, Peter G; Crewther, ratios significantly mediated the relationship between
David P MMN latency and SPQ-interpersonal scores, but only
partially mediated the relationship between MMN
Cognitive Neuroscience Unit, School of Psychology, Deakin latency and AQ-communication scores. These findings
University, Geelong, Victoria, Australia; Centre for Human support the growing body of literature pointing toward
Psychopharmacology, Faculty of Heath, Arts and Design, an excitation-inhibition imbalance that is central to
Swinburne University of Technology, Melbourne, Victoria, psychosocial functioning across multi-dimensional
Australia. Electronic address: [email protected]; spectrum disorders, such as autism and schizophrenia,
Centre for Mental Health, Faculty of Heath, Arts and Design, and provides neurochemical indicators of the processes
Swinburne University of Technology, Melbourne, Victoria, that underlie psychosocial dysfunction.
Australia
Keywords: Autism, GABA, Glutamate, Mismatch negativity,
ABSTRACT Several lines of evidence identify aberrant Schizophrenia, Social cognition
excitatory-inhibitory neural processes across autism
and schizophrenia spectrum disorders, particularly Progress in neuro-psychopharmacology & biological
within the psychosocial domain. Such neural processes psychiatry (2020), Vol. 98 (31676468) (2 citations)
include increased excitatory glutamate and reduced
inhibitory GABA concentrations, which may affect
auditory pre-attentive processing as indexed by the Emotional face processing in autism spectrum
mismatch negativity (MMN); thus, an excitation-inhi- disorder: Effects in gamma connectivity (2020)
bition imbalance might lead to aberrant MMN, which
might in turn drive the relationship between the MMN Safar, Kristina; Yuk, Veronica; Wong, Simeon M; Leung,
and psychosocial difficulties. This research has the Rachel C; Anagnostou, Evdokia; Taylor, Margot J
potential to enhance the neurochemical understand-
ing of the relationship between electrophysiology Diagnostic Imaging, Hospital for Sick Children, Toronto,
(MMN) and behavioural/clinical measures (psychosocial Canada; Neurosciences and Mental Health Program, Re-
difficulties). Thirty-eight adults (18 male, 18-40 years) search Institute, Hospital for Sick Children, Toronto, Canada.
completed the Schizotypal Personality Questionnaire Electronic address: [email protected]; Diagnostic
(SPQ) and Autism-Spectrum Quotient (AQ). Glutamate Imaging, Hospital for Sick Children, Toronto, Canada; Neu-
and GABA concentrations in bilateral superior temporal rosciences and Mental Health Program, Research Institute,
cortex (STC) were quantified using proton magnetic Hospital for Sick Children, Toronto, Canada; Department of
resonance spectroscopy (1H-MRS) while auditory MMN Psychology, University of Toronto, Toronto, Canada; Insti-
to a duration deviant was measured with magneto- tute of Biomaterials and Biomedical Engineering, University
encephalography. Spearman correlations probed the of Toronto, Toronto, Canada; University Health Network,
relationships between STC glutamate/GABA ratios, Toronto Western Hospital, Toronto, Canada; Autism Research
MMN amplitude and latency, and AQ and SPQ dimen- Centre, Bloorview Research Institute, Holland Bloorview Kids
sions. Mediation effects of glutamate/GABA ratios on Rehabilitation Hospital, Toronto, Canada
the relationship between MMN and AQ-SPQ dimen-
sions were probed using causal mediation analysis. ABSTRACT Impairments in social functioning are char-
Only SPQ-interpersonal and AQ-communication were acteristic of autism spectrum disorder (ASD). Differenc-
significantly correlated with right hemisphere gluta- es in functional networks during face processing in ASD
mate/GABA ratios and MMN latency (ps < 0.05), which compared to controls have been reported; however,

 ontents  Index 35
C