Split-brain is a lay term to describe the result when the corpus callosum connecting the two hemispheres of the brain is severed to some degree. The corpus callosum is a structure of the Mammalian Brain in the longitudinal fissure that connects the left and right Cerebral hemispheres It also facilitates The brain is the center of the Nervous system in animals All Vertebrates and the majority of Invertebrates have a brain The surgical operation to produce this condition is called corpus callosotomy. Corpus callosotomy (or less frequently callotomy) is a Surgical procedure that disconnects the Cerebral hemispheres resulting in a condition called It is performed rarely, usually as a last resort in otherwise intractable epilepsy: to mitigate the risk of accidental physical injury by reducing the severity and violence of epileptic seizures. Epilepsy is a common chronic Neurological disorder that is characterized by recurrent unprovoked seizures.
A patient with a split brain, when shown an image in his or her left visual field (that is, the left half of what both eyes see), will be unable to name what he or she has seen. This is because the speech-control center is in the left side of the brain in most people, and the image from the left visual field is sent only to the right side of the brain. Since communication between the two sides of the brain is inhibited, the patient cannot name what the right side of the brain is seeing. The person can, however, pick up and show recognition of an object (one within the left overall visual field) with their left hand, since that hand is controlled by the right side of the brain.
Some of the earliest split-brain research was carried out by Roger Wolcott Sperry, and continued when he was joined by Michael Gazzaniga. Roger Wolcott Sperry ( August 20, 1913 – April 17, 1994) was a neuropsychologist, neurobiologist and Nobel laureate who Michael S Gazzaniga (born December 12 1939) is a professor of Psychology at the University of California Santa Barbara, where he heads the Results from this research have led to important theories on the lateralization of brain function. A Longitudinal fissure separates the Human brain into two distinct Cerebral hemispheres connected by the Corpus callosum.
Split-brain patients may sometimes confabulate a rational account of their behavior, if the true motivations cannot be reported since they may depend on processing in the linguistically inaccessible right side of the brain. Confabulation, also known as false memory is the confusion of Imagination with Memory, and/or the confusion of true memories with false memories
There are some theories that the different hemispheres may have different "personalities" and contradictory goals.
External links
- Detail on the callosotomy procedure from epilepsy. com
- Interesting summary with further links to follow
- An animated game that illustrates the split-brain experiments.
- Split Brain Demonstration Video