Is texture-density contrast an inhibition or an adaptation?

Abstract

MACKAY'S recent experiments on texture-density contrast¹ are an interesting contribution to the current, rapidly-growing literature on ‘feature-specific inhibition’ in the visual system. There have been suggestions, based mainly on psychophysical evidence, that there is mutual inhibition between ‘channels’ selective for binocular disparity², orientation^3,4 and spatial frequency^5,6. It is known that many neurones in the visual cortex respond selectively to particular values on these three dimensions^7–9 (as well as others, such as direction and velocity). Our knowledge of lateral inhibition at earlier levels in the visual pathway indicates that mutual inhibition between such multi-channel neurons would account for a wide range of visual effects.