title: Distinct roles for inhibition in spatial and temporal tuning of local edge detectors in the rabbit retina.
abstract: This paper examines the role of inhibition in generating the receptive-field properties of local edge detector (LED) ganglion cells in the rabbit retina. We confirm that the feed-forward inhibition is largely glycinergic but, contrary to a recent report, our data demonstrate that the glycinergic inhibition contributes to temporal tuning for the OFF and ON inputs to the LEDs by delaying the onset of spiking; this delay was more pronounced for the ON inputs (∼ 340 ms) than the OFF inputs (∼ 12 ms). Blocking glycinergic transmission reduced the delay to spike onset and increased the responses to flickering stimuli at high frequencies. Analysis of the synaptic conductances indicates that glycinergic amacrine cells affect temporal tuning through both postsynaptic inhibition of the LEDs and presynaptic modulation of the bipolar cells that drive the LEDs. The results also confirm that presynaptic GABAergic transmission contributes significantly to the concentric surround antagonism in LEDs; however, unlike presumed LEDs in the mouse retina, the surround is only partly generated by spiking amacrine cells.
authors.affiliation: Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, United States of America.
authors.forename: Sowmya
authors.initials: S
authors.lastname: Venkataramani
authors.affiliation: Institute of Animal Pathology, University of Bern, Bern, Switzerland.
authors.forename: Michiel
authors.initials: M
authors.lastname: Van Wyk
authors.affiliation: Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, United States of America.
authors.forename: Ilya
authors.initials: I
authors.lastname: Buldyrev
authors.affiliation: Australian Research Council Centre of Excellence in Vision Science, Queensland Brain Institute, The University of Queensland, Brisbane, Australia.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Sivyer
authors.affiliation: Australian Research Council Centre of Excellence in Vision Science, Queensland Brain Institute, The University of Queensland, Brisbane, Australia.
authors.forename: David I
authors.initials: DI
authors.lastname: Vaney
authors.affiliation: Department of Ophthalmology, Oregon Health and Science University, Portland, Oregon, United States of America.
authors.forename: W Rowland
authors.initials: WR
authors.lastname: Taylor
mesh_terms: D000200:Action Potentials / Q000502:physiology; D025042:Amacrine Cells / Q000378:metabolism; D000818:Animals; D018684:Glycine Agents / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011817:Rabbits; D012160:Retina / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000502:physiology*; D013331:Strychnine / Q000494:pharmacology; D009435:Synaptic Transmission / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D018684:Glycine Agents; D013779:Tetrodotoxin; D013331:Strychnine