The cerebral cortex is made up of two hemispheres. Thus there is a “right half brain” and “a left half brain”. These two halves are directly connected by a thick, ribbon like band across the bottom called corpus callosum. The left half of the brain receives messages from and sends messages to the right side of the body. The right half of the brain does this for the left side of the body.
Normally the two hemispheres work together as a co-ordinate unit and corpus callosum acts as a part of both the hem
ispheres. But studies since the earlier part of 20th century reveal that the cerebral hemispheres are not really equivalent. For example, damage to the left hemisphere often seems to result in severe language problems. Similar damage to the right hemisphere seldom has that effect.
ispheres. But studies since the earlier part of 20th century reveal that the cerebral hemispheres are not really equivalent. For example, damage to the left hemisphere often seems to result in severe language problems. Similar damage to the right hemisphere seldom has that effect.In the early 1960s, Sperry and his colleagues at the California Institute of Technology started treating epileptics by cutting the corpus callosum. The intent was to stop the spread of seizures from one hemisphere to the other. These operations cut the direct communication between the two hemispheres. Results based on the studies done on these split brain patients had been startling.
The subjects were asked to stare at a spot on a projection screen while pictures of various objects were projected to the right of the spot. They were able to identify the objects verbally. They were able to pick them out of a group of h
idden objects using their right hands to feel each object. When pictures of objects were shown on the left side of the projections screen, they could pick out the objects by feeling with their left hands, but they were unable to say what the objects were! When objects were projected on the left side of the screen, split brain patients reported that they had seen ‘nothing’ on the screen, even though they could accurately identify the objects when given a chance to touch and feel them with their left hands.
idden objects using their right hands to feel each object. When pictures of objects were shown on the left side of the projections screen, they could pick out the objects by feeling with their left hands, but they were unable to say what the objects were! When objects were projected on the left side of the screen, split brain patients reported that they had seen ‘nothing’ on the screen, even though they could accurately identify the objects when given a chance to touch and feel them with their left hands. In short, the two hemispheres differs in the receiving the information from and sending it to the different sides of the body. They also differ in performing mental functions. In most people, the left hemisphere is dominant in verbal tasks, such as identifying spoken and printed words. However, there are some recent evidence that right hemisphere too has some role in verbal skills.
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