Desynchronization of fronto-temporal networks during working memory processing in autism.
BACKGROUND
Mounting evidence suggests that autism is a network disorder, characterized by atypical brain connectivity, especially in the context of high level cognitive processes such as working memory (WM). Accordingly, atypical WM processes have been related to the social and cognitive deficits observed in children with autism spectrum disorder (ASD).


METHODS
We used magnetoencephalography (MEG) to investigate connectivity differences during a high memory load (2-back) WM task between 17 children with ASD and 20 age-, sex-, and IQ-matched controls.


RESULTS
We identified reduced inter-regional alpha-band (9-15 Hz) phase synchronization in children with ASD during the WM task. Reduced WM-related brain synchronization encompassed fronto-temporal networks (ps < 0.04 corrected) previously associated with challenging high-level conditions (i.e. the left insula and the anterior cingulate cortex (ACC)) and memory encoding and/or recognition (i.e. the right middle temporal gyrus and the right fusiform gyrus). Additionally, we found that reduced connectivity processes related to the right fusiform were correlated with the severity of symptoms in children with ASD, suggesting that such atypicalities could be directly related to the behavioural deficits observed.


CONCLUSIONS
This study provides new evidence of atypical long-range synchronization in children with ASD in fronto-temporal areas that crucially contribute to challenging WM tasks, but also emotion regulation and social cognition processes. Thus, these results support the network disorder hypothesis of ASD and argue for a specific pathophysiological contribution of brain processes related to working memory and executive functions on the symptomatology of autism.
Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Canada.|Neuroscience & Mental Health Program, The Hospital for Sick Children Research Institute, Toronto, Canada.
Charline
C
Urbain
Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Canada.|Neuroscience & Mental Health Program, The Hospital for Sick Children Research Institute, Toronto, Canada.
Vanessa M
VM
Vogan
Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Canada.|Neuroscience & Mental Health Program, The Hospital for Sick Children Research Institute, Toronto, Canada.
Annette X
AX
Ye
Neuroscience & Mental Health Program, The Hospital for Sick Children Research Institute, Toronto, Canada.|Division of Neurology, The Hospital for Sick Children, Toronto, Canada.
Elizabeth W
EW
Pang
Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada.
Sam M
SM
Doesburg
Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Canada.|Neuroscience & Mental Health Program, The Hospital for Sick Children Research Institute, Toronto, Canada.|Department of Psychology, University of Toronto, Toronto, Canada.
Margot J
MJ
Taylor
D000293:Adolescent; D000513:Alpha Rhythm / Q000502:physiology; D001321:Autistic Disorder / Q000150:complications* / Q000473:pathology*; D016022:Case-Control Studies; D002648:Child; D004569:Electroencephalography; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008569:Memory Disorders / Q000209:etiology*; D008570:Memory, Short-Term / Q000502:physiology*; D009415:Nerve Net / Q000503:physiopathology*; D011601:Psychophysics; D013223:Statistics as Topic; D013702:Temporal Lobe / Q000503:physiopathology*
MEG; alpha oscillations; children; executive functions; phase-locking values