title: A retinal source of spatial contrast gain control.
abstract: Sensory cortex is able to encode a broad range of stimulus features despite a great variation in signal strength. In cat primary visual cortex (V1), for example, neurons are able to extract stimulus features like orientation or spatial configuration over a wide range of stimulus contrasts. The contrast-invariant spatial tuning found in V1 neuron responses has been modeled as a gain control mechanism, but at which stage of the visual pathway it emerges has remained unclear. Here we describe our findings that contrast-invariant spatial tuning occurs not only in the responses of lateral geniculate nucleus (LGN) relay cells but also in their afferent retinal input. Our evidence suggests that a similar contrast-invariant mechanism is found throughout the stages of the early visual pathway, and that the contrast-invariant spatial selectivity is evident in both retinal ganglion cell and LGN cell responses.
authors: Center for Perceptual Systems, Section of Neurobiology, School of Biological Sciences, College of Natural Sciences, The University of Texas at Austin, Austin, Texas 78712, USA.
authors: Benjamin
authors: B
authors: Scholl
authors: Kenneth W
authors: KW
authors: Latimer
authors: Nicholas J
authors: NJ
authors: Priebe
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002415:Cats; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D005829:Geniculate Bodies / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000502:physiology*; D009949:Orientation / Q000502:physiology; D010775:Photic Stimulation; D012160:Retina / Q000502:physiology*; D013028:Space Perception / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology