title: Electrical synaptic input to ganglion cells underlies differences in the output and absolute sensitivity of parallel retinal circuits.
abstract: Parallel circuits throughout the CNS exhibit distinct sensitivities and responses to sensory stimuli. Ambiguities in the source and properties of signals elicited by physiological stimuli, however, frequently obscure the mechanisms underlying these distinctions. We found that differences in the degree to which activity in two classes of Off retinal ganglion cell (RGC) encode information about light stimuli near detection threshold were not due to obvious differences in the cells' intrinsic properties or the chemical synaptic input the cells received; indeed, differences in the cells' light responses were largely insensitive to block of fast ionotropic glutamate receptors. Instead, the distinct responses of the two types of RGCs likely reflect differences in light-evoked electrical synaptic input. These results highlight a surprising strategy by which the retina differentially processes and routes visual information and provide new insight into the circuits that underlie responses to stimuli near detection threshold.
authors.affiliation: Howard Hughes Medical Institute and Department of Physiology & Biophysics, University of Washington, Seattle, Washington 98195-7290, USA. murphyg@janelia.hhmi.org
authors.forename: Gabe J
authors.initials: GJ
authors.lastname: Murphy
authors.forename: Fred
authors.initials: F
authors.lastname: Rieke
mesh_terms: D000818:Animals; D002450:Cell Communication / Q000502:physiology; D054351:Electrical Synapses / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009434:Neural Pathways / Q000502:physiology; D009924:Organ Culture Techniques; D010775:Photic Stimulation / Q000379:methods; D058468:Receptors, Ionotropic Glutamate / Q000037:antagonists & inhibitors / Q000502:physiology; D012160:Retina / Q000166:cytology / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000502:physiology* / Q000648:ultrastructure; D012680:Sensitivity and Specificity; D012684:Sensory Thresholds / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*; D014785:Vision, Ocular / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology
chemical_list: D058468:Receptors, Ionotropic Glutamate