inferior colliculus
Summary
The inferior colliculus is a midbrain structure that relays auditory information from the brainstem up to the thalamus and helps orient the head toward sounds. Most testable point: it is for hearing, while the superior colliculus is for vision.
Detail
Meaning: The inferior colliculus is one of a pair of bumps on the dorsal midbrain (the tectum). It receives auditory input from lower brainstem nuclei and relays it to the medial geniculate nucleus of the thalamus, which projects to the auditory cortex in the temporal lobe. It also helps locate sounds and supports reflexive turning toward a sudden noise.
On the MCAT: Expect questions that ask you to order the auditory pathway: cochlea → auditory nerve → cochlear nucleus → superior olive → inferior colliculus → medial geniculate nucleus → auditory cortex. Another format describes damage to a midbrain region and asks which function is impaired, or asks you to pair each structure with its sense.
Common confusion: Students swap the colliculi and the geniculate nuclei. The colliculi sit in the midbrain; the geniculate nuclei sit in the thalamus. The inferior colliculus and medial geniculate nucleus serve hearing. The superior colliculus and lateral geniculate nucleus serve vision, with the superior colliculus mainly driving reflexive eye and head movements toward visual stimuli. Memory aid: superior goes with sight, medial goes with sound.
Sources
- Psychology (Myers)
- Biological Psychology (Kalat)
- Neuroscience (Purves)
Written for the MCAT and checked before it was published. For study reference only. Spotted an error? Let us know.