Nucleus · one in each half of the brain

Inferior colliculus

The hearing hub of the midbrain, a key relay for sound signals on their way up.

The inferior colliculi are two small bumps on the back of the midbrain, just below the superior colliculi. Sound signals from your ears pass through them on their way to the thalamus and the hearing cortex. Here, clues from both ears are combined to help work out where a sound is coming from. They also help you jump and turn at sudden noises.

Where it is

On the back of the midbrain, just below the superior colliculi. It is the lower pair of four small bumps.

What it does

Hearing relay

It is a key relay stop for sound signals heading up to the cortex.

Locating sounds

It combines tiny differences in timing and loudness between your two ears to pinpoint where a sound comes from.

Sorting pitch

Its cells are laid out like the keys of a piano, in order from low notes to high notes.

Startle and turn

It helps trigger your jump at a sudden bang and turn your head toward it.

Think of it as a central train station for sound: signals from the ears change trains here before heading up to the cortex.

Works with

Vestibulocochlear nerve (VIII)Sound signals start in this nerve and climb through the brainstem to reach it.
Medial geniculate nucleusIts next stop is this hearing relay in the thalamus.
Primary auditory cortexFrom the thalamus, its signals reach the primary hearing cortex.
Superior colliculusIt shares sound-location information with its neighbor above, helping you turn toward sounds.

When it goes wrong

Hearing problems

Damage here can make it hard to hear clearly or to tell where sounds are coming from.

Ringing in the ears

Research suggests that changes in activity here may play a part in tinnitus, a constant ringing or buzzing in the ears.

For learning only, not medical advice. If you have a health concern, talk to a doctor.

Surprising facts

It helps filter out sounds you make yourself, like chewing and breathing.

Where the name comes from

Latin for "lower little hill". It is the lower pair of small hills on the back of the midbrain.

Learn it in a lesson

Hearing and balanceFrom the inner ear to the cortex. A short guided lesson in 3D.

Quick quiz

3 questions. Your answers are saved and come back in your daily review.

Which of these is a job of the inferior colliculus?
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Hearing relay. It is a key relay stop for sound signals heading up to the cortex.
The inferior colliculus is part of which larger structure?
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Midbrain. It belongs to the midbrain.
Which part fits this description? "Like a central train station for sound: signals from the ears change trains here before heading up to the cortex."
Show the answer
Inferior colliculus. It is the inferior colliculus. The hearing hub of the midbrain, a key relay for sound signals on their way up.

Sources

Neuroanatomy, Inferior Colliculus, StatPearls, NCBI Bookshelf
The midbrain, Queensland Brain Institute, University of Queensland

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Explore the inferior colliculus in 3D

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