Orientation Contrast Sensitivity from Long-range Interactions in Visual Cortex

Part of Advances in Neural Information Processing Systems 9 (NIPS 1996)

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Klaus Pawelzik, Udo Ernst, Fred Wolf, Theo Geisel


Recently Sill ito and coworkers (Nature 378, pp. 492,1995) demon(cid:173) strated that stimulation beyond the classical receptive field (cRF) can not only modulate, but radically change a neuron's response to oriented stimuli. They revealed that patch-suppressed cells when stimulated with contrasting orientations inside and outside their cRF can strongly respond to stimuli oriented orthogonal to their nominal preferred orientation. Here we analyze the emergence of such complex response patterns in a simple model of primary vi(cid:173) sual cortex. We show that the observed sensitivity for orientation contrast can be explained by a delicate interplay between local isotropic interactions and patchy long-range connectivity between distant iso-orientation domains. In particular we demonstrate that the observed properties might arise without specific connections be(cid:173) tween sites with cross-oriented cRFs.