Deficits in the processing of visual context associated with schizophrenia S C Dakin1, M S Tibber1, E Anderson2, V Robol3 |
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1Institute of Ophthalmology, University College London, United Kingdom |
| There is now emerging consensus that poorer processing of context is a significant contributor to visual deficits associated with schizophrenia. I will review evidence relating to the nature and neural locus of the context-processing deficit and how it can produce performance deficits that can be misattributed to a failure to integrate visual information. Specifically I will report: (1) Reduced surround suppression in SZ extends across some visual dimensions (e.g. contrast, size) but not others (e.g. luminance) suggesting a cortical locus for this deficit. (2) Patients show a reduced susceptibility to the influence of a disruptive-context both (a) when detecting contours (so that people with SZ produce relatively better performance) and (b) when judging orientation of contour-elements (i.e. patients show proportionally less crowding) (3) Poor contour-context processing and generally noisier representation of local orientation explain deficits in contour detection associated with SZ (rather than an integration deficit per se). (4) fMRI reveals smaller population receptive fields (pRF) in early visual cortical areas of people with SZ which could explain these perceptual differences. |
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