Cochlear nuclei

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The cochlear nuclei are a group of two small special sensory nuclei in the upper medulla for the cochlear nerve component of the vestibulocochlear nerve. They are part of the extensive cranial nerve nuclei within the brainstem.

Gross Anatomy

The dorsal and ventral nuclei are located in the dorsolateral upper medulla and are separated by the fibers of the inferior cerebellar peduncle:

  • the ventral cochlear nucleus is ventral and lateral to the dorsal cochlear nucleus and separates the cochlear and vestibular fibers of the vestibulocochlear nerve
  • the dorsal cochlear nucleus is dorsal to the inferior cerebellar peduncle and ventral nucleus and forms the auditory tubercle which is a small bulge on the dorsal aspect of the restiform body

From both nuclei, second-order sensory neurons project superiorly into the pons as part of the ascending auditory pathway.

Cochlear afferent fibers enter the brainstem at the pontomedullary junction lateral to the facial nerve as part of the vestibulocochlear nerve.

Innervation

The nucleus houses the sensory cell bodies of the cochlear nerve which relay auditory information to the auditory components of the brainstem.