inferior colliculus

Predominantly grey matter elevations on the dorsal aspect of the midbrain make up the inferior colliculus, a paired part of the midbrain tectum. Its position is defined by three neighbours: it lies caudal to the superior colliculus, dorsal to the periaqueductal grey of the cerebral aqueduct, and rostral to the cerebellum. Its internal organisation comprises three nuclei, the central, pericentral, and external nuclei, together with two structures that are predominantly white matter, the brachium of the inferior colliculus and the commissure of the inferior colliculus. It is also designated the caudal colliculus, a name distinguishing it from its rostral counterpart, and it is classified within the nervous system as a regional part of the brain.