The Cerebellum

Introduction

• The cerebellum is a distinct part of the brain, separate from the cerebrum.
• It is located behind the brain stem and below the cerebrum.
• Divided into two hemispheres: left cerebellar hemisphere and right cerebellar hemisphere.

Position in the Brain

• Cerebrum is on top with right and left cerebral hemispheres.
• Brain stem connects to the spinal cord.
• Cerebellum is behind the brain stem, visible more from the back view.

Function

• Primary Function: Coordinates movement.
  • Smooths out and makes movements more accurate.
  • Plays a role in accuracy when touching objects.

Information Flow in Cerebellum

1. Motor Plan
   • Information about which muscles need to contract, how intensely, and for how long.
   • This information comes from cerebral hemispheres and is sent to the cerebellum.
2. Position Sense Information
   • Information on the actual movement happening.
   • Includes inputs from muscle spindles sensing muscle stretch.
   • This information is unconscious.
3. Feedback
   • Compares motor plan and actual movement.
   • Sends feedback to motor areas of the cerebrum to correct movements.

Anatomy Notes

• Middle cerebellum coordinates movements of the body’s center (e.g., walking).
• Side cerebellum coordinates limb movements.
• Involves in speech through coordination of muscles in lips, tongue, throat.
• Coordinates eye movements.

Conclusion

• The cerebellum is critical for movement coordination, using various types of information.
• Further anatomy details and pathways are more advanced topics beyond this introduction.