a brain in which the two cerebral hemispheres have been separated by partial or complete destruction of the corpus callosum (see commissurotomy), thereby blocking direct communication between them. Split-brain surgery is used to treat otherwise intractable epilepsy, because it prevents cortical seizure activity from spreading between the hemispheres. Given the extensive communication between the two hemispheres in the intact brain, disruption of this activity in split-brain conditions is of considerable scientific interest. Also called divided brain.