Processing of Real-World, Dynamic Natural Stimuli in Autism is Linked to Corticobasal Function.

Many individuals with autism spectrum disorder (ASD) have been shown to perceive everyday sensory information differently compared to peers without autism. Research examining these sensory differences has primarily utilized nonnatural stimuli or natural stimuli using static photos with few having utilized dynamic, real-world nonverbal stimuli. Therefore, in this study, we used functional magnetic resonance imaging to characterize brain activation of individuals with high-functioning autism when viewing and listening to a video of a real-world scene (a person bouncing a ball) and anticipating the bounce. We investigated both multisensory and unisensory processing and hypothesized that individuals with ASD would show differential activation in (a) primary auditory and visual sensory cortical and association areas, and in (b) cortical and subcortical regions where auditory and visual information is integrated (e.g. temporal-parietal junction, pulvinar, superior colliculus). Contrary to our hypotheses, the whole-brain analysis revealed similar activation between the groups in these brain regions. However, compared to controls the ASD group showed significant hypoactivation in the left intraparietal sulcus and left putamen/globus pallidus. We theorize that this hypoactivation reflected underconnectivity for mediating spatiotemporal processing of the visual biological motion stimuli with the task demands of anticipating the timing of the bounce event. The paradigm thus may have tapped into a specific left-lateralized aberrant corticobasal circuit or loop involved in initiating or inhibiting motor responses. This was consistent with a dual "when versus where" psychophysical model of corticobasal function, which may reflect core differences in sensory processing of real-world, nonverbal natural stimuli in ASD. Autism Res 2020, 13: 539-549.