title: Synchronous spikes are necessary but not sufficient for a synchrony code in populations of spiking neurons.
abstract: Synchronous activity in populations of neurons potentially encodes special stimulus features. Selective readout of either synchronous or asynchronous activity allows formation of two streams of information processing. Theoretical work predicts that such a synchrony code is a fundamental feature of populations of spiking neurons if they operate in specific noise and stimulus regimes. Here we experimentally test the theoretical predictions by quantifying and comparing neuronal response properties in tuberous and ampullary electroreceptor afferents of the weakly electric fishApteronotus leptorhynchusThese related systems show similar levels of synchronous activity, but only in the more irregularly firing tuberous afferents a synchrony code is established, whereas in the more regularly firing ampullary afferents it is not. The mere existence of synchronous activity is thus not sufficient for a synchrony code. Single-cell features such as the irregularity of spiking and the frequency dependence of the neuron's transfer function determine whether synchronous spikes possess a distinct meaning for the encoding of time-dependent signals.
authors.affiliation: Institute for Neurobiology, Eberhard Karls Universität, 72076 Tuebingen, Germany; jan.grewe@uni-tuebingen.de.
authors.forename: Jan
authors.initials: J
authors.lastname: Grewe
authors.affiliation: Bernstein Center for Computational Neuroscience, 10115 Berlin, Germany.|Department of Physics, Humboldt Universität zu Berlin, 12489 Berlin, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kruscha
authors.affiliation: Bernstein Center for Computational Neuroscience, 10115 Berlin, Germany.|Department of Physics, Humboldt Universität zu Berlin, 12489 Berlin, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Lindner
authors.affiliation: Institute for Neurobiology, Eberhard Karls Universität, 72076 Tuebingen, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Benda
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D004558:Electric Stimulation; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods; D023702:Gymnotiformes / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D059010:Single-Cell Analysis / Q000295:instrumentation / Q000379:methods
keywords: electric fish; mutual information; oscillations; population code; synchrony