Texture-surround suppression of contour-shape coding in human vision.

Contextual influences on neurons in the primary visual cortex have largely been studied using simple visual stimuli and their functional role is still poorly understood. Using a novel visual after-effect of perceived shape we show psychophysically that the coding of a contour's shape is inhibited by nearby parallel, but not orthogonal texture orientations. This suggests that neurons in the visual cortex that are suppressed by parallel orientations feed their outputs into higher visual areas that are involved in the processing of contour shape and in the recognition of objects.