title: Nonlinear dendritic integration of electrical and chemical synaptic inputs drives fine-scale correlations.
abstract: Throughout the CNS, gap junction-mediated electrical signals synchronize neural activity on millisecond timescales via cooperative interactions with chemical synapses. However, gap junction-mediated synchrony has rarely been studied in the context of varying spatiotemporal patterns of electrical and chemical synaptic activity. Thus, the mechanism underlying fine-scale synchrony and its relationship to neural coding remain unclear. We examined spike synchrony in pairs of genetically identified, electrically coupled ganglion cells in mouse retina. We found that coincident electrical and chemical synaptic inputs, but not electrical inputs alone, elicited synchronized dendritic spikes in subregions of coupled dendritic trees. The resulting nonlinear integration produced fine-scale synchrony in the cells' spike output, specifically for light stimuli driving input to the regions of dendritic overlap. In addition, the strength of synchrony varied inversely with spike rate. Together, these features may allow synchronized activity to encode information about the spatial distribution of light that is ambiguous on the basis of spike rate alone.
authors.affiliation: Department of Biology, University of Victoria, Victoria, British Columbia, Canada.
authors.forename: Stuart
authors.initials: S
authors.lastname: Trenholm
authors.affiliation: Department of Biology, University of Victoria, Victoria, British Columbia, Canada.
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: McLaughlin
authors.affiliation: Department of Physics, Princeton University, Princeton, New Jersey, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Schwab
authors.affiliation: Department of Physiology and Biophysics, University of Washington, Seattle, Washington, USA.
authors.forename: Maxwell H
authors.identifier: 0000000241649995
authors.initials: MH
authors.lastname: Turner
authors.affiliation: Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Smith
authors.affiliation: Department of Physiology and Biophysics, University of Washington, Seattle, Washington, USA.
authors.forename: Fred
authors.initials: F
authors.lastname: Rieke
authors.affiliation: Department of Biology, University of Victoria, Victoria, British Columbia, Canada.
authors.forename: Gautam B
authors.initials: GB
authors.lastname: Awatramani
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D003712:Dendrites / Q000187:drug effects / Q000502:physiology*; D005260:Female; D017629:Gap Junctions / Q000187:drug effects / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D017711:Nonlinear Dynamics; D010775:Photic Stimulation / Q000379:methods*; D010852:Picrotoxin / Q000494:pharmacology; D013569:Synapses / Q000187:drug effects / Q000502:physiology*
chemical_list: D010852:Picrotoxin