Somatosensory influence on the cochlear nucleus and beyond

Hear Res. Jun-Jul 2006;216-217:90-9. doi: 10.1016/j.heares.2006.01.006. Epub 2006 Mar 2.

Abstract

Interactions between somatosensory and auditory systems occur at peripheral levels in the central nervous system. The cochlear nucleus (CN) receives innervation from trigeminal sensory structures: the ophthalmic division of the trigeminal ganglion and the caudal and interpolar regions of the spinal trigeminal nucleus (Sp5I and Sp5C). These projections terminate primarily in the granule cell domain, but also in magnocellular regions of the ventral and dorsal CN. Additionally, new evidence is presented demonstrating that cells in the lateral paragiganticular regions of the reticular formation (RF) also project to the CN. Not unlike the responses obtained from electrically stimulating the trigeminal system, stimulating RF regions can also result in excitation/inhibition of dorsal CN neurons. The origins and central connections of these projection neurons are associated with systems controlling vocalization and respiration. Electrical stimulation of trigeminal and RF projection neurons can suppress acoustically driven activity of not only CN neurons, but also neurons in the inferior colliculus. Together with the anatomical observations, these physiological observations suggest that one function of somatosensory input to the auditory system is to suppress responses to "expected" body-generated sounds such as vocalization or respiration. This would serve to enhance responses to "unexpected" externally-generated sounds, such as the vocalizations of other animals.

Publication types

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

MeSH terms

  • Acoustic Stimulation
  • Animals
  • Auditory Pathways / anatomy & histology
  • Auditory Pathways / physiology*
  • Cochlear Nucleus / anatomy & histology
  • Cochlear Nucleus / cytology
  • Cochlear Nucleus / physiology*
  • Electric Stimulation
  • Humans
  • Inferior Colliculi / cytology
  • Inferior Colliculi / physiology
  • Neurons / physiology
  • Reticular Formation / cytology
  • Reticular Formation / physiology
  • Somatosensory Cortex / anatomy & histology
  • Somatosensory Cortex / physiology*
  • Trigeminal Ganglion / anatomy & histology
  • Trigeminal Ganglion / physiology
  • Trigeminal Nerve / anatomy & histology
  • Trigeminal Nerve / physiology*