title: Visual surround suppression in schizophrenia.
abstract: Compared to unaffected observers patients with schizophrenia (SZ) show characteristic differences in visual perception, including a reduced susceptibility to the influence of context on judgments of contrast - a manifestation of weaker surround suppression (SS). To examine the generality of this phenomenon we measured the ability of 24 individuals with SZ to judge the luminance, contrast, orientation, and size of targets embedded in contextual surrounds that would typically influence the target's appearance. Individuals with SZ demonstrated weaker SS compared to matched controls for stimuli defined by contrast or size, but not for those defined by luminance or orientation. As perceived luminance is thought to be regulated at the earliest stages of visual processing our findings are consistent with a suppression deficit that is predominantly cortical in origin. In addition, we propose that preserved orientation SS in SZ may reflect the sparing of broadly tuned mechanisms of suppression. We attempt to reconcile these data with findings from previous studies.
authors: Institute of Ophthalmology, University College London London, UK ; NIHR Biomedical Research Centre at Moorfields Eye Hospital London, UK.
authors: Marc S
authors: MS
authors: Tibber
authors: Elaine J
authors: EJ
authors: Anderson
authors: Tracy
authors: T
authors: Bobin
authors: Elena
authors: E
authors: Antonova
authors: Alice
authors: A
authors: Seabright
authors: Bernice
authors: B
authors: Wright
authors: Patricia
authors: P
authors: Carlin
authors: Sukhwinder S
authors: SS
authors: Shergill
authors: Steven C
authors: SC
authors: Dakin
keywords: contrast; cortex; luminance; orientation; perception; schizophrenia; size; surround suppression