Making connections in the inner ear: recent insights into the development of spiral ganglion neurons and their connectivity with sensory hair cells

Semin Cell Dev Biol. 2013 May;24(5):460-9. doi: 10.1016/j.semcdb.2013.04.003. Epub 2013 May 6.


In mammals, auditory information is processed by the hair cells (HCs) located in the cochlea and then rapidly transmitted to the CNS via a specialized cluster of bipolar afferent connections known as the spiral ganglion neurons (SGNs). Although many anatomical aspects of SGNs are well described, the molecular and cellular mechanisms underlying their genesis, how they are precisely arranged along the cochlear duct, and the guidance mechanisms that promote the innervation of their hair cell targets are only now being understood. Building upon foundational studies of neurogenesis and neurotrophins, we review here new concepts and technologies that are helping to enrich our understanding of the development of the nervous system within the inner ear.

Publication types

  • Review

MeSH terms

  • Animals
  • Cell Movement
  • Cochlear Duct / cytology
  • Cochlear Duct / growth & development
  • Cochlear Duct / innervation
  • Cochlear Duct / physiology*
  • Gene Expression Regulation, Developmental
  • Hair Cells, Auditory / cytology
  • Hair Cells, Auditory / physiology*
  • Humans
  • Ion Channels / genetics
  • Ion Channels / metabolism
  • Mechanotransduction, Cellular
  • Nerve Growth Factors / genetics*
  • Nerve Growth Factors / metabolism
  • Neurogenesis / physiology*
  • Sensory Receptor Cells / cytology
  • Sensory Receptor Cells / physiology*
  • Spiral Ganglion / cytology
  • Spiral Ganglion / growth & development
  • Spiral Ganglion / innervation
  • Spiral Ganglion / physiology*
  • Synapses / physiology
  • Synaptic Transmission


  • Ion Channels
  • Nerve Growth Factors