Stronger Neural Modulation by Visual Motion Intensity in Autism Spectrum Disorders

Abstract

Theories of autism spectrum disorders (ASD) have focused on altered perceptual integration of sensory features as a possible core deficit. Yet, there is little understanding of the neuronal processing of elementary sensory features in ASD. For typically developed individuals, we previously established a direct link between frequency-specific neural activity and the intensity of a specific sensory feature: Gamma-band activity in the visual cortex increased approximately linearly with the strength of visual motion. Using magnetoencephalography (MEG), we investigated whether in individuals with ASD neural activity reflect the coherence, and thus intensity, of visual motion in a similar fashion. Thirteen adult participants with ASD and 14 control participants performed a motion direction discrimination task with increasing levels of motion coherence. A polynomial regression analysis revealed that gamma-band power increased significantly stronger with motion coherence in ASD compared to controls, suggesting excessive visual activation with increasing stimulus intensity originating from motion-responsive visual areas V3, V6 and hMT/V5. Enhanced neural responses with increasing stimulus intensity suggest an enhanced response gain in ASD. Response gain is controlled by excitatory-inhibitory interactions, which also drive high-frequency oscillations in the gamma-band. Thus, our data suggest that a disturbed excitatory-inhibitory balance underlies enhanced neural responses to coherent motion in ASD.

Altered beta-band oscillations and connectivity underlie detail-oriented visual processing in autism

“…Interestingly, these visual and attentional mechanisms have all been reported to be anomalous in ASD in previous behavioral studies (for reviews see Dakin and Frith, 2005;Simmons et al, 2009;Keehn et al, 2013Robertson and Baron-Cohen, 2017). Overall, these results suggest that beta oscillations might be a relevant target for neurophysiological studies testing altered neural oscillations during visual processing in ASD, similarly to what have been recently shown for gamma band oscillations (Sun et al, 2012;Peiker et al, 2015) and alpha-gamma coupling (Seymour et al, 2019). and attentional tasks, including crowding, in the present study we employed high-density electroencephalography (EEG) in participants with ASD to investigate the neurophysiological (ERPs) and oscillatory correlates of local visual processing within a crowding regime, and to study the underlying network activity and connectivity pattern at the level of cortical sources.…”

Altered Onset Response Dynamics in Somatosensory Processing in Autism Spectrum Disorder

“…These results are also intriguing in the context of a recent finding of increased inter-trial variability in ASD (Dinstein et al, 2012 ). Unmodulated, i.e., inconsistently gain controlled, feedforward inputs, as observed previously in ASD (Peiker et al, 2015 ), would likely result in more variable trial to trial onset responses. Lastly, these results are also relevant in the context of the high prevalence of behavioral sensory hypo- and hyper- sensitivities in ASD (Tommerdahl et al, 2007 ; Marco et al, 2011 , 2012 ).…”

Dysregulated Oscillatory Connectivity in the Visual System in Autism Spectrum Disorder

“…Reduced gamma coherence in the visual cortex was also reported by Peiker et al (2015a), who utilised a paradigm requiring the identification of moving objects presented through a narrow slit, necessitating the integration of perceptual information across time. However, another study by the same group, reported greater modulation of total gamma power in response to visual motion intensity for ASD participants (Peiker, Schneider, et al, 2015b).…”