ABSTRACT
Primary auditory afferents bifurcate to form terminals in both the ventral and dorsal cochlear nuclei. From the ventral cochlear nucleus axons run to the superior olivary complex (SOC) on both sides and the contralateral inferior colliculus (IC). Central auditory pathways process three features of sound input in parallel: tone, loudness and timing. From the last two the brain calculates the location of the sound in space. Parallel processing begins in the cochlear nuclei. Some regions of auditory cortex are less well tonotopically organized and contain cells that respond to a wider range of frequencies. The IC connects extensively with the deep layers of the superior colliculus to form an auditory space map in register with the retinotopic map. Hence the superior colliculus is implicated in the auditory reflexes organizing gaze and head rotation towards the sound source.
