title: Spatiotemporal characteristics of surround suppression in primary visual cortex and lateral geniculate nucleus of the cat.
abstract: In the primary visual cortex (V1), a neuronal response to stimulation of the classical receptive field (CRF) is predominantly suppressed by a stimulus presented outside the CRF (extraclassical receptive field, ECRF), a phenomenon referred to as ECRF suppression. To elucidate the neuronal mechanisms and origin of ECRF suppression in V1 of anesthetized cats, we examined the temporal properties of the spatial extent and orientation specificity of ECRF suppression in V1 and the lateral geniculate nucleus (LGN), using stationary-flashed sinusoidal grating. In V1, we found three components of ECRF suppression: (1) local and fast, (2) global and fast, and (3) global and late. The local and fast component, which resulted from within 2° of the boundary of the CRF, started no more than 10 ms after the onset of the CRF response and exhibited low specificity for the orientation of the ECRF stimulus. These spatiotemporal properties corresponded to those of geniculate ECRF suppression, suggesting that the local and fast component of V1 is inherited from the LGN. In contrast, the two global components showed rather large spatial extents ∼5° from the CRF boundary and high specificity for orientation, suggesting that their possible origin is the cortex, not the LGN. Correspondingly, the local component was observed in all neurons of the thalamocortical recipient layer, while the global component was biased toward other layers. Therefore, we conclude that both subcortical and cortical mechanisms with different spatiotemporal properties are involved in ECRF suppression.
authors.affiliation: Graduate School of Medicine, Osaka University, Toyonaka, Osaka, Japan; Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Osaka, Japan; and shimegi@vision.hss.osaka-u.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Shimegi
authors.affiliation: Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Osaka, Japan; and.
authors.forename: Ayako
authors.initials: A
authors.lastname: Ishikawa
authors.affiliation: Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kida
authors.affiliation: Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Osaka, Japan; and.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sakamoto
authors.affiliation: Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Osaka, Japan; and.
authors.forename: Sin-Ichiro
authors.initials: S
authors.lastname: Hara
authors.affiliation: Graduate School of Medicine, Osaka University, Toyonaka, Osaka, Japan; Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Osaka, Japan; and.
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Sato
mesh_terms: D000818:Animals; D002415:Cats; D005829:Geniculate Bodies / Q000502:physiology*; D008839:Microelectrodes; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D013997:Time Factors; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
keywords: contextual modulation; extraclassical receptive field; size tuning; surround suppression