title: The role of the visual cortex in response properties of lateral geniculate cells in rats.
abstract: Unitary discharges of the lateral geniculate nucleus (LGN) were analyzed in anesthetized and paralyzed rats after inactivation of visual cortical areas (VC) by cryoblockade or by depositing a cotton wick soaked in KCl (3 M). The receptive fields were mapped prior to and following the interruption of the cortico-geniculate feedback. The responsiveness of the VC was controlled by monitoring evoked potentials and the EEG. In most off-center and about half on-center cells the surround excitatory responses were markedly reduced and even totally abolished. In contrast, the center excitation remained unchanged or increased suggesting a parallel decline of the inhibitory surround. This differential influence of cortical blockade on on- or off-responses failed to appear in on-off cells whose receptive field was nonconcentrically organized. It is proposed that the VC exerts a complex influence upon geniculate physiology while the spatial center-surround relationships are under the control of the VC. The results of this investigation are comparable to those obtained in rabbits and cats.
mesh_terms: D000818:Animals; D002415:Cats; D013181:Cortical Spreading Depression / Q000187:drug effects; D005071:Evoked Potentials / Q000187:drug effects; D005829:Geniculate Bodies / Q000502:physiology*; D009897:Optic Chiasm / Q000502:physiology; D011189:Potassium Chloride / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D013045:Species Specificity; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception
chemical_list: D011189:Potassium Chloride