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

Highlights • Local visual processing in ASD were investigated with EEG during a crowding task. • Target discrimination in presence of interfering flankers predicted ASD symptoms. • ASD group did not show beta desynchronization for resolving visual crowding scenes. • Altered beta response reflected atypical occipital–inferotemporal connectivity. • Altered beta connectivity in ASD may reflect abnormal long-range interactions.
Sensory and perceptual anomalies may have a major impact on basic cognitive and social skills in humans. Autism Spectrum Disorder (ASD) represents a special perspective to explore this relationship, being characterized by both these features. The present study employed electroencephalography (EEG) to test whether detail-oriented visual perception, a recognized hallmark of ASD, is associated with altered neural oscillations and functional connectivity in the beta frequency band, considering its role in feedback and top-down reentrant signalling in the typical population. Using a visual crowding task, where participants had to discriminate a peripheral target letter surrounded by flankers at different distances, we found that detail-oriented processing in children with ASD, as compared to typically developing peers, could be attributed to anomalous oscillatory activity in the beta band (15–30 Hz), while no differences emerged in the alpha band (8–12 Hz). Altered beta oscillatory response reflected in turn atypical functional connectivity between occipital areas, where the initial stimulus analysis is accomplished, and infero-temporal regions, where objects identity is extracted. Such atypical beta connectivity predicted both ASD symptomatology and their detail-oriented processing. Overall, these results might be explained by an altered feedback connectivity within the visual system, with potential cascade effects in visual scene parsing and higher order functions.