The inferior colliculus is a part of the midbrain that serves as a main auditory (sound) center for the body. It acts as the channel for almost all auditory signals in the human body. Its primary roles are signal integration, frequency recognition, and pitch discrimination. It also processes sensory signals from the superior colliculi, located above it.
The inferior colliculus is made up of two lobes, which process sound signals from both ears. It is sub-divided into the external cortex, lateral cortex, and central cortex. It also performs the function of integrating multiple audio signals that help to filter out sounds from vocalizing, breathing, and chewing activities.
This part of the brain shows a comparatively higher rate of metabolic activity than several other areas of the brain. Metabolic activity is the name given to the chemical reactions that are necessary to maintain life.
A range of brain stem nuclei — collections of neurons, or gray matter — connect to the inferior colliculus. All of them attach to the core nucleus bilaterally (at both lobes) with the exception of the lateral lemniscus, a bundle of sensory nerve fibers that comes from the cochlear nucleus of the brain stem. Some of the lateral lemniscus nerves run into the thalamus and the temporal lobe cortex, where the integration of cognitive and sensory signals occurs.