Dysregulated Oscillatory Connectivity in the Visual System in Autism Spectrum Disorder

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Autism Spectrum Disorder (ASD) is increasingly associated with atypical perceptual and sensory symptoms. Here we explore the hypothesis that aberrant sensory processing in ASD could be linked to atypical intra- (local) and inter-regional (global) brain connectivity. To elucidate oscillatory dynamics and connectivity in the visual domain we used magnetoencephalography (MEG) and a simple visual grating paradigm with a group of 18 adolescent autistic participants and 18 typically developing controls. Both groups showed similar increases in gamma (40-80Hz) and decreases in alpha (8-13Hz) frequency power in occipital cortex. However, systematic group differences emerged when analysing local and global connectivity in detail. Firstly, directed connectivity was estimated using non-parametric Granger causality between visual areas V1 and V4. Feedforward V1-to-V4 connectivity, mediated by gamma oscillations, was equivalent between ASD and control groups, but importantly, feedback V4-to-V1 connectivity, mediated by alpha (8-14Hz) oscillations, was significantly reduced in the ASD group. This reduction was correlated with autistic traits, indicating an atypical visual hierarchy in autism, with reduced top-down modulation of visual input via alpha-band oscillations. Secondly, at the local level in V1, coupling of alpha-phase to gamma amplitude (alpha-gamma PAC) was reduced in the ASD group. This implies dysregulated local visual processing, with gamma oscillations decoupled from patterns of wider alpha-band phase synchrony, possibly due to an excitation-inhibition imbalance. More generally, these results are in agreement with predictive coding accounts of neurotypical perception and indicate that visual processes in autism are less modulated by contextual feedback information.


  • Dysregulated Oscillatory Connectivity in the Visual System in Autism Spectrum Disorder

    Accepted author manuscript, 7 MB, PDF-document

    Embargo ends: 1/01/50


Original languageEnglish
Publication statusAccepted/In press - 20 May 2019

Bibliographic note

Funding: Wellcome Trust, Dr Hadwen Trust and Tommy’s Fund, The Netherlands Organisation for Scientific Research (NWO Vidi: 864.14.011), PhD studentship from Aston University and Macquarie University.


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