Macaque striate cortex: pattern, movement and colour processing.

Simple cells in the primate visual cortex provide a form of generalized, pre-cognitive mapping of visual scenes. One point in space is represented by several orientation-specific cells capable of signalling both standing contrast and contrast changes in the scene. The arrangement of simple receptive fields (with a few antagonistic subregions) suggest analysis of scenes both in terms of symmetrical and antisymmetrical spatial components (i.e. lines and edges) and spatial-frequency contents. There is no evidence that this analysis is carried out within fixed areas (or patches) since a diversity of receptive field sizes was observed. A chromatic content is probably analysed by a different class of cells with concentric, cone-opponent receptive fields.