Sometimes a person's corpus callosum is split, which separates the two hemispheres completely. this is done to

a. study the effects of a split brain.

b. change a person's personality.

c. determine the precise area of cognitive functioning.

d. control epilepsy.

The corpus callosom is a bundle/band of nerve fibers found deep inside the brain. This connects the right and left hemisphere. Corpus Callosotomy or otherwise known as "Split-Brain" surgery is a procedure where the corpus callosum is cut. This is done to control epilepsy but only as a last resort.

The surgeon can partially or completely cut the corpus callosom. If a partial dissection is enough to control seizures, they would stop there. However, if the seizures goes uncontrolled, it is completely dissected.