Corpus Callosum

About the Corpus Callosum

The corpus callosum is a broad, flat band of nerve fibers lying beneath the cerebral cortex at the midline of the brain, and it is the largest white matter structure in the brain, containing on the order of 200 million axons. It connects corresponding areas of the left and right cerebral hemispheres, allowing them to share sensory, motor, and cognitive information and to work together. It is divided anatomically into the rostrum, genu, body, and splenium. In the mid twentieth century, surgeons cut the corpus callosum in some people with severe epilepsy to stop seizures from spreading between hemispheres, and research on these split brain patients by Roger Sperry and Michael Gazzaniga revealed specialized functions of each hemisphere, work recognized by a Nobel Prize in 1981. Agenesis of the corpus callosum, in which the structure fails to develop, is one of the more common brain malformations and has highly variable effects.