THE ROLE OF THE PRIMARY VISUAL-CORTEX IN HIGHER-LEVEL VISION

In the classical feed-forward, modular view of visual processing, the primary visual cortex (area V1) is a module that serves to extract loc al features such as edges and bars. Representation and recognition of objects are thought to be functions of higher extrastriate cortical ar eas. This paper presents neurophysiological data that show the later p art of V1 neurons' responses reflecting higher order perceptual comput ations related to Ullman's (Cognition 1984;18:97-159) visual routines and Marr's (Vision NJ: Freeman 1982) full primal sketch, 21/2D sketch and 3D model. Based on theoretical reasoning and the experimental evid ence, we propose a possible reinterpretation of the functional role of V1. In this framework, because of V1 neurons' precise encoding of ori entation and spatial information, higher level perceptual computations and representations that involve high resolution details, fine geomet ry and spatial precision would necessarily involve V1 and be reflected in the later part of its neurons' activities. (C) 1998 Elsevier Scien ce Ltd. All rights reserved.