Mean { Field Model of V 1

In this paper, we derive a model for analyzing the innuence of local cortical connections on the activities of neurons in V1. A set of orientation columns is arranged according to a measured orientation map. Orientation columns are connected by local excitatory and slightly more distributed inhibitory bers. Based on this geometrical model we demonstrate that (i) sharp and contrast{invariant orientation tuning curves are combined with contrast saturation, (ii) the strength of cortical ampliication can be localized in orientation space and (iii) anisotropic contextual suppression by iso{oriented anking stimuli arises as an emergent property and can be mediated by local connections.