Contextual effects by short range connections in a mean-field model of V1

In this paper, we derive a model for analyzing the influence of local corti cal connections on the activities of neurons in V1. A set of orientation co lumns is arranged according to a measured orientation map. Orientation colu mns are connected by local excitatory and slightly more distributed inhibit ory fibers. Based on this geometrical model we demonstrate that (i) sharp a nd contrast-invariant orientation tuning curves are combined with contrast saturation, (ii) the strength of cortical amplification can be localized in orientation space and (iii) anisotropic contextual suppression by iso-orie nted flanking stimuli arises as an emergent property and can be mediated by local connections. (C) 2001 Published by Elsevier Science B.V.