Weaker visual surround suppression in both autism spectrum and psychosis spectrum disorders

Issues with sensory functioning and attention are common in both autism spectrum and psychosis spectrum disorders. Despite important differences in symptoms and developmental time course, these conditions share a number of common features with regard to visual perception. One such phenomenon that we and others have observed in both populations is a reduced effect of surrounding spatial context during the perception of basic visual features such as contrast or motion. In this talk, we will consider whether these differences in visual function may have a common source. In a series of psychophysical, and brain imaging experiments, we found that young adults with ASD showed weaker visual surround suppression during motion perception, as compared to neurotypical individuals. This was reflected by differences in behavioral task performance and fMRI responses from area MT. Likewise, across multiple experiments in people with psychosis, we have found that individuals with schizophrenia show weaker behavioral and neural surround suppression during visual contrast perception. Recently, we used a divisive normalization model to show that narrower spatial attention may be sufficient to explain weaker surround suppression in ASD. This theory was subsequently given support by another group who showed weaker suppression for narrow vs. broad attention conditions in healthy adults. Previous studies have also found narrower spatial attention both in people with ASD and in schizophrenia. Thus, we suggest narrower attention may be a common sensory difference that is sufficient to account for weaker surround suppression across both ASD and schizophrenia, versus neurotypicals.