title: Predicted contextual modulation varies with distance from pinwheel centers in the orientation preference map.
abstract: In the primary visual cortex (V1) of some mammals, columns of neurons with the full range of orientation preferences converge at the center of a pinwheel-like arrangement, the 'pinwheel center' (PWC). Because a neuron receives abundant inputs from nearby neurons, the neuron's position on the cortical map likely has a significant impact on its responses to the layout of orientations inside and outside its classical receptive field (CRF). To understand the positional specificity of responses, we constructed a computational model based on orientation preference maps in monkey V1 and hypothetical neuronal connections. The model simulations showed that neurons near PWCs displayed weaker but detectable orientation selectivity within their CRFs, and strongly reduced contextual modulation from extra-CRF stimuli, than neurons distant from PWCs. We suggest that neurons near PWCs robustly extract local orientation within their CRF embedded in visual scenes, and that contextual information is processed in regions distant from PWCs.
authors.affiliation: Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan. okamoto@digital.med.kyushu-u.ac.jp
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Okamoto
authors.forename: Koji
authors.initials: K
authors.lastname: Ikezoe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tamura
authors.forename: Masataka
authors.initials: M
authors.lastname: Watanabe
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Aihara
authors.forename: Ichiro
authors.initials: I
authors.lastname: Fujita
mesh_terms: D000818:Animals; D001931:Brain Mapping; D008251:Macaca / Q000502:physiology; D008959:Models, Neurological; D009949:Orientation / Q000502:physiology; D010775:Photic Stimulation; D014793:Visual Cortex / Q000033:anatomy & histology* / Q000502:physiology*