The cerebral hemispheres are connected by fiber tracts which permit the hemispheres to communicate with one another. The major connection is the corpus callosum, a second is the fornix. The hemispheres normally divide up the tasks with one hemisphere, usually the left, being dominant. This is the principle of lateralization and dominance. In most people (90 to 95%) the left hemisphere is dominant and responsible for logic, mathematics, and language. The right hemisphere is the center for emotions and artistic endeavors. However, when one hemisphere is damaged the other may be capable of performing the lost functions.