Origin and Segmental Diversity of Spinal Inhibitory Interneurons

Lora B. Sweeney, Jay B. Bikoff, Mariano I. Gabitto, Susan Brenner-Morton, Myungin Baek, Jerry H. Yang, Esteban G. Tabak, Jeremy S. Dasen, Christopher R. Kintner, Thomas M. Jessell

Research output: Contribution to journalArticlepeer-review


Motor output varies along the rostro-caudal axis of the tetrapod spinal cord. At limb levels, ∼60 motor pools control the alternation of flexor and extensor muscles about each joint, whereas at thoracic levels as few as 10 motor pools supply muscle groups that support posture, inspiration, and expiration. Whether such differences in motor neuron identity and muscle number are associated with segmental distinctions in interneuron diversity has not been resolved. We show that select combinations of nineteen transcription factors that specify lumbar V1 inhibitory interneurons generate subpopulations enriched at limb and thoracic levels. Specification of limb and thoracic V1 interneurons involves the Hox gene Hoxc9 independently of motor neurons. Thus, early Hox patterning of the spinal cord determines the identity of V1 interneurons and motor neurons. These studies reveal a developmental program of V1 interneuron diversity, providing insight into the organization of inhibitory interneurons associated with differential motor output. Sweeney et al. show that the diversity of spinal inhibitory interneurons, defined by combinatorial transcription factor expression, differs along the body axis in correspondence with limb and thoracic motor output. Hox genes, not motor neurons, specify segmental differences in inhibitory interneuron identity.

Original languageEnglish (US)
Pages (from-to)341-355.e3
Issue number2
StatePublished - Jan 17 2018


  • Hox proteins
  • cell identity
  • development
  • inhibitory interneurons
  • motor circuit
  • spinal cord patterning
  • transcription factor

ASJC Scopus subject areas

  • General Neuroscience


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