title: Subthreshold membrane conductances enhance directional selectivity in vertebrate sensory neurons.
abstract: Directional selectivity, in which neurons respond preferentially to one "preferred" direction of movement over the opposite "null" direction, is a critical computation that is found in the central nervous systems of many animals. Such responses are generated using two mechanisms: spatiotemporal convergence via pathways that differ in the timing of information from different locations on the receptor array and the nonlinear integration of this information. Previous studies have showed that various mechanisms may act as nonlinear integrators by suppressing the response in the null direction. Here we show, through a combination of mathematical modeling and in vivo intracellular recordings, that subthreshold membrane conductances can act as a nonlinear integrator by increasing the response in the preferred direction of motion only, thereby enhancing the directional bias. Such subthreshold conductances are ubiquitous in the CNS and therefore may be used in a wide array of computations that involve the enhancement of an existing bias arising from differential spatiotemporal filtering.
authors.affiliation: Department of Physiology, Center for Nonlinear Dynamics, McGill University, Montreal, Quebec, Canada.
authors.forename: Maurice J
authors.initials: MJ
authors.lastname: Chacron
authors.forename: Eric S
authors.initials: ES
authors.lastname: Fortune
mesh_terms: D000465:Algorithms; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D018118:Chloride Channels / Q000037:antagonists & inhibitors; D004555:Electric Fish / Q000502:physiology; D004558:Electric Stimulation; D055724:Electrophysiological Phenomena; D007473:Ion Channels / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology; D008959:Models, Neurological; D015233:Models, Statistical; D009039:Motion Perception / Q000502:physiology; D009068:Movement / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology; D017711:Nonlinear Dynamics; D009949:Orientation / Q000502:physiology*; D011984:Sensory Receptor Cells / Q000502:physiology*; D026941:Sodium Channel Blockers / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D018118:Chloride Channels; D007473:Ion Channels; D026941:Sodium Channel Blockers
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