title: A new code for contrast in the primate visual pathway.
abstract: We characterize a hitherto undocumented type of neuron present in the regions bordering the principal layers of the macaque lateral geniculate nucleus. Neurons of this type were distinguished by a high and unusually regular maintained discharge that was suppressed by spatiotemporal modulation of luminance or chromaticity within the receptive field. The response to any effective stimulus was a reduction in discharge, reminiscent of the "suppressed-by-contrast" cells of the cat retina. To a counterphase-modulated grating, the response was a phase-insensitive suppression modulated at twice the stimulus frequency, implying a receptive field comprised of multiple mechanisms that generate rectifying responses. This distinctive nonlinearity makes the neurons well suited to computing a measure of contrast energy; such a signal might be important in regulating sensitivity early in visual cortex.
authors.affiliation: Center for Neural Science, New York University, New York, New York 10003, USA. ctailby@unimelb.edu.au
authors.forename: Chris
authors.initials: C
authors.lastname: Tailby
authors.forename: Samuel G
authors.initials: SG
authors.lastname: Solomon
authors.forename: Neel T
authors.initials: NT
authors.lastname: Dhruv
authors.forename: Najib J
authors.initials: NJ
authors.lastname: Majaj
authors.forename: Sach H
authors.initials: SH
authors.lastname: Sokol
authors.forename: Peter
authors.initials: P
authors.lastname: Lennie
mesh_terms: D000818:Animals; D015350:Contrast Sensitivity / Q000502:physiology*; D008252:Macaca fascicularis; D008297:Male; D010775:Photic Stimulation / Q000379:methods*; D014794:Visual Fields / Q000502:physiology; D014795:Visual Pathways / Q000502:physiology*