cell, but each inner hair cell is innervated by up to 30 such nerve fibers, depending on species and location within the cochlea. Type II neurons make up the remaining 5-10% of the neurons and innervate the outer hair cells. They have relatively small diameters, are unipolar, and are unmyelinated. Cochlear nuclear complex In mammals, the axons from each cochlear nerve terminate in the cochlear nuclear complex that is ipsilaterally located in the medulla of the brainstem. The cochlear nucleus is the first 'relay station' of the central auditory system and receives mainly ipsilateral afferent input. The three major components of the cochlear nuclear complex are (see figure below): the dorsal cochlear nucleus (DCN) the anteroventral cochlear nucleus (AVCN) the posteroventral cochlear nucleus (PVCN) Each of the three cochlear nuclei are tonotopically organized. The axons from the low-frequency region of the cochlea project to the ventral portion of the dorsal cochlear nucleus and the ventrolateral portions of the anteroventral cochlear nucleus. The axons from the high-frequency region project to the dorsal portion of the anteroventral cochlear nucleus and the uppermost dorsal portions of the dorsal cochlear nucleus. The axons from the intermediate frequency region project to intermediate targets, such that tonotopy is preserved between the cochlea and the cochlear nuclei. See also Cochlear implant Auditory Brainstem Response References Additional images External links Illustration at cytochemistry.net Auditory system Otology Audiology