V1 and v2b interneurons secure the alternating flexor-extensor motor activity mice require for limbed locomotion

Neuron. 2014 Apr 2;82(1):138-50. doi: 10.1016/j.neuron.2014.02.013.


Reciprocal activation of flexor and extensor muscles constitutes the fundamental mechanism that tetrapod vertebrates use for locomotion and limb-driven reflex behaviors. This aspect of motor coordination is controlled by inhibitory neurons in the spinal cord; however, the identity of the spinal interneurons that serve this function is not known. Here, we show that the production of an alternating flexor-extensor motor rhythm depends on the composite activities of two classes of ventrally located inhibitory neurons, V1 and V2b interneurons (INs). Abrogating V1 and V2b IN-derived neurotransmission in the isolated spinal cord results in a synchronous pattern of L2 flexor-related and L5 extensor-related locomotor activity. Mice lacking V1 and V2b inhibition are unable to articulate their limb joints and display marked deficits in limb-driven reflex movements. Taken together, these findings identify V1- and V2b-derived neurons as the core interneuronal components of the limb central pattern generator (CPG) that coordinate flexor-extensor motor activity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / drug effects
  • Action Potentials / genetics
  • Action Potentials / physiology
  • Animals
  • Animals, Newborn
  • Cholera Toxin / metabolism
  • Embryo, Mammalian
  • Extremities / physiology*
  • Functional Laterality / drug effects
  • Functional Laterality / genetics
  • Interneurons / physiology*
  • Locomotion / drug effects
  • Locomotion / genetics
  • Locomotion / physiology*
  • Mice
  • Mice, Transgenic
  • Motor Activity / drug effects
  • Motor Activity / genetics
  • Motor Activity / physiology*
  • Muscle, Skeletal / cytology
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / physiology
  • Mutation / genetics
  • Neural Inhibition / drug effects
  • Neural Inhibition / genetics
  • Neural Inhibition / physiology*
  • Neurotransmitter Agents / pharmacology
  • Reflex / drug effects
  • Reflex / physiology*
  • Spinal Cord / cytology
  • Tail / innervation


  • Neurotransmitter Agents
  • Cholera Toxin