Nucleus · one in each half of the brain
Medial geniculate nucleus
Also called MGN, Medial geniculate body
The hearing relay: the sounds you hear pass through this little bent knee.
The medial geniculate nucleus is the thalamus's station for hearing. Sound signals travel from the ear through several stops in the brainstem to the inferior colliculus, then here, and then up to the hearing cortex in the temporal lobe. It is arranged by pitch, from low to high, like the keys of a piano. Part of it also sends sounds to the amygdala, linking what you hear to emotion.
Where it is
On the underside of the back of the thalamus, just inward from the lateral geniculate nucleus and below the pulvinar.
What it does
Hearing relay
It passes sound signals from the inferior colliculus up to the hearing cortex.
A map of pitch
It is laid out by pitch, from low to high, like the keys of a piano.
Timing and patterns
It helps track the timing and patterns in sound, which matter for understanding speech.
Alarm sounds
It also passes sounds to the amygdala, which can set off a fear reaction automatically, before you have had time to think about what you heard.
Think of it as a switchboard for sound, sorting every incoming call by pitch before passing it upstairs.
Works with
- Inferior colliculusThe midbrain hearing station that sends it sound signals.
- Acoustic radiationThe fiber bundle that carries its output to the hearing cortex.
- Primary auditory cortexThe primary hearing cortex that receives its signals.
- Superior temporal gyrusA larger hearing area that helps make sense of sounds and speech.
- AmygdalaGets sound signals from it, useful for alarm reactions.
When it goes wrong
Damage on one side
Most of the hearing pathway gets input from both ears, so losing one MGN is unlikely to cause deafness, though it may make it harder to tell where sounds come from.
For learning only, not medical advice. If you have a health concern, talk to a doctor.
Surprising facts
- Like its neighbor for vision, it is named for its knee-like bend.
Where the name comes from
"Geniculate" comes from Latin "genu", meaning "knee", after its bent shape. "Medial" means toward the middle.
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 medial geniculate nucleus?
Show the answer
Hearing relay. It passes sound signals from the inferior colliculus up to the hearing cortex.
Hearing relay. It passes sound signals from the inferior colliculus up to the hearing cortex.
The medial geniculate nucleus is part of which larger structure?
Show the answer
Thalamus. It belongs to the thalamus.
Thalamus. It belongs to the thalamus.
Which part fits this description? "Like a switchboard for sound, sorting every incoming call by pitch before passing it upstairs."
Show the answer
Medial geniculate nucleus. It is the medial geniculate nucleus. The hearing relay: the sounds you hear pass through this little bent knee.
Medial geniculate nucleus. It is the medial geniculate nucleus. The hearing relay: the sounds you hear pass through this little bent knee.
These parts now come back in your daily review, just before you would forget them.
Practice it and its neighbors in 3DSources
- The Auditory Thalamus, Neuroscience (Purves et al.), NCBI Bookshelf
- Auditory Pathway, StatPearls, NCBI Bookshelf
- 13.3 What Is the Contribution of Brain Structures in Emotional States?, OpenStax, Introduction to Behavioral Neuroscience
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Explore the medial geniculate nucleus in 3D
Turn it around, zoom inside and see how it connects to the rest of the brain, then test yourself with quick quizzes.
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