title: Activity Regulates the Incidence of Heteronymous Sensory-Motor Connections.
abstract: The construction of spinal sensory-motor circuits involves the selection of appropriate synaptic partners and the allocation of precise synaptic input densities. Many aspects of spinal sensory-motor selectivity appear to be preserved when peripheral sensory activation is blocked, which has led to a view that sensory-motor circuits are assembled in an activity-independent manner. Yet it remains unclear whether activity-dependent refinement has a role in the establishment of connections between sensory afferents and those motor pools that have synergistic biomechanical functions. We show here that genetically abolishing central sensory-motor neurotransmission leads to a selective enhancement in the number and density of such "heteronymous" connections, whereas other aspects of sensory-motor connectivity are preserved. Spike-timing-dependent synaptic refinement represents one possible mechanism for the changes in connectivity observed after activity blockade. Our findings therefore reveal that sensory activity does have a limited and selective role in the establishment of patterned monosynaptic sensory-motor connections.
authors.affiliation: Howard Hughes Medical Institute, Kavli Institute for Brain Science, Zuckerman Mind Brain Behavior Institute, Departments of Neuroscience and Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.
authors.forename: Alana I
authors.initials: AI
authors.lastname: Mendelsohn
authors.affiliation: Center for Motor Neuron Biology and Disease, Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA.
authors.forename: Christian M
authors.initials: CM
authors.lastname: Simon
authors.affiliation: Center for Theoretical Neuroscience, Departments of Physiology and Neuroscience, Columbia University, New York, NY 10032, USA.
authors.forename: L F
authors.initials: LF
authors.lastname: Abbott
authors.affiliation: Center for Motor Neuron Biology and Disease, Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA.
authors.forename: George Z
authors.initials: GZ
authors.lastname: Mentis
authors.affiliation: Howard Hughes Medical Institute, Kavli Institute for Brain Science, Zuckerman Mind Brain Behavior Institute, Departments of Neuroscience and Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA. Electronic address: tmj1@columbia.edu.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Jessell
mesh_terms: D000818:Animals; D008666:Metalloendopeptidases / Q000494:pharmacology; D051379:Mice; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation* / Q000502:physiology; D009466:Neuromuscular Blocking Agents / Q000494:pharmacology; D009475:Neurons, Afferent / Q000187:drug effects / Q000502:physiology*; D011434:Proprioception / Q000187:drug effects / Q000502:physiology*; D013116:Spinal Cord / Q000187:drug effects / Q000502:physiology*; D013569:Synapses / Q000187:drug effects / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D013744:Tetanus Toxin / Q000494:pharmacology
chemical_list: D009466:Neuromuscular Blocking Agents; D013744:Tetanus Toxin; D008666:Metalloendopeptidases; C093556:zinc-endopeptidase, tetanus neurotoxin