title: Direction-selective dendritic action potentials in rabbit retina.
abstract: Dendritic spikes that propagate toward the soma are well documented, but their physiological role remains uncertain. Our in vitro patch-clamp recordings and two-photon calcium imaging show that direction-selective retinal ganglion cells (DSGCs) utilize orthograde dendritic spikes during physiological activity. DSGCs signal the direction of image motion. Excitatory subthreshold postsynaptic potentials are observed in DSGCs for motion in all directions and provide a weakly tuned directional signal. However, spikes are generated over only a narrow range of motion angles, indicating that spike generation greatly enhances directional tuning. Our results indicate that spikes are initiated at multiple sites within the dendritic arbors of DSGCs and that each dendritic spike initiates a somatic spike. We propose that dendritic spike failure, produced by local inhibitory inputs, might be a critical factor that enhances directional tuning of somatic spikes.
authors.affiliation: Neurological Sciences Institute, Oregon Health and Sciences University, Beaverton, Oregon 97006, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Oesch
authors.forename: Thomas
authors.initials: T
authors.lastname: Euler
authors.forename: W Rowland
authors.initials: WR
authors.lastname: Taylor
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D003712:Dendrites / Q000502:physiology*; D003952:Diagnostic Imaging; D004594:Electrophysiology; D066298:In Vitro Techniques; D009039:Motion Perception / Q000502:physiology*; D009949:Orientation / Q000502:physiology; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D011817:Rabbits; D012160:Retina / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D000779:Anesthetics, Local; D013779:Tetrodotoxin; D002118:Calcium