title: EM connectomics reveals axonal target variation in a sequence-generating network.
abstract: The sequential activation of neurons has been observed in various areas of the brain, but in no case is the underlying network structure well understood. Here we examined the circuit anatomy of zebra finch HVC, a cortical region that generates sequences underlying the temporal progression of the song. We combined serial block-face electron microscopy with light microscopy to determine the cell types targeted by HVC(RA)neurons, which control song timing. Close to their soma, axons almost exclusively targeted inhibitory interneurons, consistent with what had been found with electrical recordings from pairs of cells. Conversely, far from the soma the targets were mostly other excitatory neurons, about half of these being other HVC(RA)cells. Both observations are consistent with the notion that the neural sequences that pace the song are generated by global synaptic chains in HVC embedded within local inhibitory networks.
authors.affiliation: Max Planck Institute of Neurobiology, Martinsried, Germany.
authors.forename: Jörgen
authors.identifier: 0000-0002-2547-8700
authors.initials: J
authors.lastname: Kornfeld
authors.affiliation: NYU Neuroscience Institute and Department of Otolaryngology, New York University Langone Medical Center, New York, United States.|Center for Neural Science, New York University, New York, United States.
authors.forename: Sam E
authors.identifier: 0000-0001-7889-898X
authors.initials: SE
authors.lastname: Benezra
authors.affiliation: Computational Neuroanatomy Group, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.|Bernstein Center for Computational Neuroscience, Tübingen, Germany.|Center of Advanced European Studies and Research, Bonn, Germany.
authors.forename: Rajeevan T
authors.initials: RT
authors.lastname: Narayanan
authors.affiliation: Max Planck Institute of Neurobiology, Martinsried, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Svara
authors.affiliation: NYU Neuroscience Institute and Department of Otolaryngology, New York University Langone Medical Center, New York, United States.|Center for Neural Science, New York University, New York, United States.
authors.forename: Robert
authors.identifier: 0000-0003-0849-6904
authors.initials: R
authors.lastname: Egger
authors.affiliation: Computational Neuroanatomy Group, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.|Bernstein Center for Computational Neuroscience, Tübingen, Germany.|Center of Advanced European Studies and Research, Bonn, Germany.
authors.forename: Marcel
authors.initials: M
authors.lastname: Oberlaender
authors.affiliation: Max Planck Institute of Neurobiology, Martinsried, Germany.
authors.forename: Winfried
authors.identifier: 0000-0002-0704-6998
authors.initials: W
authors.lastname: Denk
authors.affiliation: NYU Neuroscience Institute and Department of Otolaryngology, New York University Langone Medical Center, New York, United States.|Center for Neural Science, New York University, New York, United States.
authors.forename: Michael A
authors.identifier: 0000-0002-9283-3741
authors.initials: MA
authors.lastname: Long
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000033:anatomy & histology*; D063132:Connectome; D008853:Microscopy; D009415:Nerve Net; D046109:Passeriformes / Q000033:anatomy & histology*
keywords: birdsong; connectomics; neural sequences; neuroscience; synfire chains; zebra finch