Inferior colliculus

The inferior colliculus (IC) (Latin for lower hill) is the principal midbrain nucleus of the auditory pathway and receives input from several peripheral brainstem nuclei in the auditory pathway, as well as inputs from the auditory cortex. The inferior colliculus has three subdivisions: the central nucleus, a dorsal cortex by which it is surrounded, and an external cortex which is located laterally. Its bimodal neurons are implicated in auditory-somatosensory interaction, receiving projections from somatosensory nuclei. This multisensory integration may underlie a filtering of self-effected sounds from vocalization, chewing, or respiration activities.Superficial dissection of brain-stem. Lateral view.Deep dissection of brain-stem. Lateral view.Dissection of brain-stem. Dorsal view.Hind- and mid-brains; postero-lateral view.Posterior dissection of brainstem with colliculi visible.Fourth ventricle. Posterior view.Deep dissection.Brainstem. Posterior view. The inferior colliculus (IC) (Latin for lower hill) is the principal midbrain nucleus of the auditory pathway and receives input from several peripheral brainstem nuclei in the auditory pathway, as well as inputs from the auditory cortex. The inferior colliculus has three subdivisions: the central nucleus, a dorsal cortex by which it is surrounded, and an external cortex which is located laterally. Its bimodal neurons are implicated in auditory-somatosensory interaction, receiving projections from somatosensory nuclei. This multisensory integration may underlie a filtering of self-effected sounds from vocalization, chewing, or respiration activities. The inferior colliculi together with the superior colliculi form the eminences of the corpora quadrigemina, and also part of the tectal region of the midbrain. The inferior colliculus lies caudal to its counterpart – the superior colliculus – above the trochlear nerve, and at the base of the projection of the medial geniculate nucleus and the lateral geniculate nucleus. The inferior colliculi of the midbrain are located just below the visual processing centers known as the superior colliculi. The inferior colliculus is the first place where vertically orienting data from the fusiform cells in the dorsal cochlear nucleus can finally synapse with horizontally orienting data. Sound location data thus becomes fully integrated by the inferior colliculus.