title: Dense distributed processing in a hindlimb scratch motor network.
abstract: In reduced preparations, hindlimb movements can be generated by a minimal network of neurons in the limb innervating spinal segments. The network of neurons that generates real movements is less well delineated. In an ex vivo carapace-spinal cord preparation from adult turtles (Trachemys scripta elegans), we show that ventral horn interneurons in mid-thoracic spinal segments are functionally integrated in the hindlimb scratch network. First, mid-thoracic interneurons receive intense synaptic input during scratching and behave like neurons in the hindlimb enlargement. Second, some mid-thoracic interneurons activated during scratching project descending axons toward the hindlimb enlargement. Third, elimination of mid-thoracic segments leads to a weakening of scratch rhythmicity. We conclude that densely innervated interneurons in mid-thoracic segments contribute to hindlimb scratching and may be part of a distributed motor network that secures motor coherence.
authors.affiliation: University of Copenhagen, Department of Neuroscience and Pharmacology, Copenhagen DK 2200, Denmark, and Vilnius University, Faculty of Natural Sciences, Department of Neurobiology and Biophysics, Vilnius LT 03101, Lithuania r.guzulaitis@gmail.com.
authors.forename: Robertas
authors.initials: R
authors.lastname: Guzulaitis
authors.affiliation: Vilnius University, Faculty of Natural Sciences, Department of Neurobiology and Biophysics, Vilnius LT 03101, Lithuania.
authors.forename: Aidas
authors.initials: A
authors.lastname: Alaburda
authors.affiliation: University of Copenhagen, Department of Neuroscience and Pharmacology, Copenhagen DK 2200, Denmark, and.
authors.forename: Jorn
authors.initials: J
authors.lastname: Hounsgaard
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D001703:Biophysics; D004558:Electric Stimulation; D005260:Female; D007839:Functional Laterality; D006614:Hindlimb / Q000502:physiology*; D066298:In Vitro Techniques; D007395:Interneurons / Q000502:physiology*; D008239:Lysine / Q000031:analogs & derivatives; D008297:Male; D009046:Motor Neurons / Q000502:physiology*; D009068:Movement / Q000187:drug effects; D009415:Nerve Net / Q000502:physiology*; D010507:Periodicity; D011597:Psychomotor Performance / Q000502:physiology*; D013116:Spinal Cord / Q000166:cytology*; D014426:Turtles
chemical_list: C013411:biocytin; D008239:Lysine
keywords: dense coding; distributed neural network; scratch reflex; spinal cord; thoracic segments
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