The cerebellum is located behind the top part of the brain stem (where the spinal cord meets the brain) and is made of two hemispheres (halves).
The cerebellum isn’t unique to humans. Evolutionarily speaking, it’s an older portion of the brain. It’s present in animals, such as apes, that scientists believe existed before humans.
It’s a relatively small portion of the brain — about 10 percent of the total weight — but it contains over half (and maybe as much as 80 percent) of the brain’s neurons. Neurons are specialized cells that transmit information via electrical signals.
The cerebellum receives information from the sensory systems, the spinal cord, and other parts of the brain and then regulates control of movements.
The cerebellum controls voluntary movements such as:
- eye movements
This control results in smooth and balanced muscular activity. The cerebellum is also important for learning motor behaviors.
Damage to the cerebellum, while not causing paralysis or intellectual impairment, might lead to:
Complex movements can become unsteady or uncontrolled. Learn more about conditions that affect the cerebellum.