Atypical spatiotemporal signatures of working memory brain processes in autism.
Working memory (WM) impairments may contribute to the profound behavioural manifestations in children with autism spectrum disorder (ASD). However, previous behavioural results are discrepant as are the few functional magnetic resonance imaging (fMRI) results collected in adults and adolescents with ASD. Here we investigate the precise temporal dynamics of WM-related brain activity using magnetoencephalography (MEG) in 20 children with ASD and matched controls during an n-back WM task across different load levels (1-back vs 2-back). Although behavioural results were similar between ASD and typically developing (TD) children, the between-group comparison performed on functional brain activity showed atypical WM-related brain processes in children with ASD compared with TD children. These atypical responses were observed in the ASD group from 200 to 600 ms post stimulus in both the low- (1-back) and high- (2-back) memory load conditions. During the 1-back condition, children with ASD showed reduced WM-related activations in the right hippocampus and the cingulate gyrus compared with TD children who showed more activation in the left dorso-lateral prefrontal cortex and the insulae. In the 2-back condition, children with ASD showed less activity in the left insula and midcingulate gyrus and more activity in the left precuneus than TD children. In addition, reduced activity in the anterior cingulate cortex was correlated with symptom severity in children with ASD. Thus, this MEG study identified the precise timing and sources of atypical WM-related activity in frontal, temporal and parietal regions in children with ASD. The potential impacts of such atypicalities on social deficits of autism are discussed.
1] Department of Diagnostic Imaging-Research, The Hospital for Sick Children, Toronto, ON, Canada [2] Neuroscience & Mental Health Program, The Hospital for Sick Children Research Institute, Toronto, ON, Canada [3] Neuropsychology and Functional Neuroimaging Research Unit at CRCN-Center for Research in Cognition and Neurosciences and UNI-ULB Neurosciences Institute, Université Libre de Bruxelles (ULB), Brussels, Belgium.
C M
CM
Urbain
1] Neuroscience & Mental Health Program, The Hospital for Sick Children Research Institute, Toronto, ON, Canada [2] Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada.
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EW
Pang
1] Department of Diagnostic Imaging-Research, The Hospital for Sick Children, Toronto, ON, Canada [2] Neuroscience & Mental Health Program, The Hospital for Sick Children Research Institute, Toronto, ON, Canada [3] Department of Psychology, University of Toronto, Toronto, ON, Canada.
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MJ
Taylor
D001321:Autistic Disorder / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods*; D002648:Child; D005260:Female; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009434:Neural Pathways / Q000503:physiopathology; D013647:Task Performance and Analysis; D013995:Time