Nucleus · one in each half of the brain
Red nucleus
Also called Nucleus ruber
A rosy, iron-rich hub in the midbrain linking the cerebellum to movement.
The red nucleus is a small, rounded cluster of cells in the midbrain. In a fresh brain it has a pinkish-red tint, thanks to the iron it contains. It gets signals from the cerebellum and the cortex and helps coordinate movement. In humans, much of its work is in a loop that helps the cerebellum learn and correct movements.
Where it is
Deep in the upper midbrain, one on each side of the midline, close to the substantia nigra.
What it does
Cerebellum relay
It receives signals from the dentate and interposed nuclei of the cerebellum.
Limb movements
It sends a small pathway down the spinal cord that helps with simple limb movements like grasping.
A learning loop
It passes signals to the inferior olive in the medulla, which sends teaching signals back to the cerebellum.
A possible backup route
After damage to the main movement pathway from the cortex, it may help with some recovery.
Think of it as a relay runner, taking the baton from the cerebellum and passing it on down the line.
Works with
- Dentate nucleusThe dentate sends it signals from the cerebellum's big side halves.
- Interposed nucleusThis nucleus sends it limb-correcting signals to pass on toward the spinal cord.
- Spinal cordIts pathway crosses to the other side and runs down the spinal cord, helping to steer the limbs.
- Medulla oblongataIt signals the inferior olive in the medulla, part of a learning loop with the cerebellum.
- Primary motor cortexThe motor cortex also sends it commands.
When it goes wrong
Holmes tremor
Damage in or near it, for example from a stroke, can cause a slow, coarse shaking that shows up at rest, when holding a position, and when moving.
Mixed symptoms
The nerve that moves the eye passes right beside it, so a small stroke here can cause a droopy eyelid and weak eye muscles on one side, and shaking on the other side of the body.
For learning only, not medical advice. If you have a health concern, talk to a doctor.
Surprising facts
- In four-legged animals like cats, its pathway to the spinal cord is a major route for walking and reaching. In humans that pathway is small, because the cortex took over most of the job.
Where the name comes from
Named simply for its reddish color. In Latin it is called nucleus ruber, "red kernel".
Quick quiz
3 questions. Your answers are saved and come back in your daily review.
Which of these is a job of the red nucleus?
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Cerebellum relay. It receives signals from the dentate and interposed nuclei of the cerebellum.
Cerebellum relay. It receives signals from the dentate and interposed nuclei of the cerebellum.
The red nucleus is part of which larger structure?
Show the answer
Midbrain. It belongs to the midbrain.
Midbrain. It belongs to the midbrain.
Which part fits this description? "Like a relay runner, taking the baton from the cerebellum and passing it on down the line."
Show the answer
Red nucleus. It is the red nucleus. A rosy, iron-rich hub in the midbrain linking the cerebellum to movement.
Red nucleus. It is the red nucleus. A rosy, iron-rich hub in the midbrain linking the cerebellum to movement.
These parts now come back in your daily review, just before you would forget them.
Practice it and its neighbors in 3DSources
- Neuroanatomy, Red Nucleus, StatPearls, NCBI Bookshelf
- Holmes Tremor, StatPearls, NCBI Bookshelf
- The midbrain, Queensland Brain Institute, University of Queensland
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Explore the red nucleus in 3D
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