Cerebellum

There's very little information that I want you to learn about the cerebellum from your book. I only want you to learn about the FUNCTION of the cerebellum here, and your book spends quite a bit of time on the anatomy of the cerebellum. Basically, there's on paragraph on page 405 about the cerebellum that actually talks about its function, and that's the only one you need to read for lecture. The rest is stuff that you'll be learning about in lab.

The cerebellum helps us coordinate our motor skills. It receives tons of proprioceptive (sensory) information from our bodies. It also receives a copy of the motor commands coming down from higher centers in the brain. Let's put these two together with an example:

	if your brain wants you to throw a ball that is in your hand, it is going to have to command your arm muscles to do that by sending a signal down to your cervical spinal cord regions.
	however, if your arm is not in a good throwing position, and you throw the ball anyway, you won't be very successful.
	proprioceptive information about your arm position gets sent to the cerebellum
	a copy of the motor command that is going down to the cervical spinal cord also gets sent to your cerebellum.
	your cerebellum compares what you want to do and the position of your body
	your cerebellum modifies the descending command so that even though your arm position is a little off, your throwing command reflects that odd position so that the throw is OK.

What happens if there's damage to the cerebellum? An example of damage that could occur is when a tumor grows within the cerebellum. The entire brain has to fit within the skull, so if a tumor starts to grow, it squeezes the brain region in which it is growing to remain fitting within the skull. If this happens in the cerebellum, the cerebellum gets damaged.

Movements become much less coordinated after any cerebellar damage. The best example of this is seen in precision movements, like end-point-contact movements. If you are asked to touch your finger to your nose, as your finger is being brought toward your nose your cerebellum normally makes corrections to the movement command so that you contact your nose (the end point) with no problem. When someone has a cerebellar lesion, the corrections are not made properly, and the person ends up shaking so much that they cannot ever touch their nose.

All movements are perturbed with cerebellar lesion. This shows just how important the cerebellum is.