title: Feedback connections and operation of the outer plexiform layer of the retina.
abstract: The primary feedback control apparatus in the outer retina is the sign-inverting feedback synapse between horizontal cells and cones. In many lower vertebrates horizontal cells release GABA in darkness, which opens Cl- channels in cones. Input-output relations of the feedback synapse reveal that the synaptic gain is light-dependent with the highest negative gain near the dark horizontal cell potential. The horizontal cell-cone feedback synapse improves the reliability of the photoreceptor output synapses. It also modulates the dynamic range and mediates color opponency and surround responses in second-order retinal neurons.
authors.affiliation: Baylor College of Medicine, Houston, Texas.
authors.forename: S M
authors.initials: SM
authors.lastname: Wu
mesh_terms: D000818:Animals; D005246:Feedback / Q000502:physiology; D006801:Humans; D010786:Photoreceptor Cells / Q000166:cytology / Q000502:physiology; D012160:Retina / Q000166:cytology / Q000502:physiology*