title: Controlling gain one photon at a time.
abstract: Adaptation is a salient property of sensory processing. All adaptational or gain control mechanisms face the challenge of obtaining a reliable estimate of the property of the input to be adapted to and obtaining this estimate sufficiently rapidly to be useful. Here, we explore how the primate retina balances the need to change gain rapidly and reliably when photons arrive rarely at individual rod photoreceptors. We find that the weakest backgrounds that decrease the gain of the retinal output signals are similar to those that increase human behavioral threshold, and identify a novel site of gain control in the retinal circuitry. Thus, surprisingly, the gain of retinal signals begins to decrease essentially as soon as background lights are detectable; under these conditions, gain control does not rely on a highly averaged estimate of the photon count, but instead signals from individual photon absorptions trigger changes in gain. DOI:http://dx.doi.org/10.7554/eLife.00467.001.
authors.affiliation: Department of Physiology and Biophysics , University of Washington , Seattle , United States ; Howard Hughes Medical Institute, University of Washington , Seattle , United States.
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Schwartz
authors.forename: Fred
authors.initials: F
authors.lastname: Rieke
mesh_terms: D000221:Adaptation, Ocular; D000222:Adaptation, Physiological; D000818:Animals; D001522:Behavior, Animal; D008251:Macaca; D010470:Perceptual Masking; D010775:Photic Stimulation; D017785:Photons; D017948:Retinal Rod Photoreceptor Cells / Q000528:radiation effects*; D012684:Sensory Thresholds; D013997:Time Factors; D014785:Vision, Ocular; D014795:Visual Pathways / Q000502:physiology / Q000528:radiation effects; D014796:Visual Perception
keywords: Other; adaptation; macaque; neural computation; retinal signal processing