commissurotomy
n. a surgical procedure involving a partial cutting of a commissure or fiber bridge, especially the great fiber bridge between the two cerebral hemispheres, the corpus callosum. A complete sectioning of the corpus callosum is called a callosectomy; this also severs its large forward portion, the anterior commissure. Complete callosectomies are now avoided if possible, in favor of partial transections. This surgery has been used to treat severe and intractable epilepsy, and it has also enabled researchers to study the isolated functions of each hemisphere. Research in this area was pioneered by Roger Sperry (see chimeric stimulation). Also called callosotomy; split-brain procedure; split-brain technique. See split brain.