Our brains are divided into two hemispheres — the right and the left, and they are connected by millions of nerve fibers that are bundled together, allowing them to communicate with each other. Now, although they usually work together it is possible to disconnect them, by cutting the corpus callosum, they can work independently.
In the 1960’s a scientist named Roger Sperry and his colleagues did some experimenting and found that cutting the corpus callosum could cure patients who had severe epilepsy. By cutting the nerve connections, known as “split brain” they stopped the misfiring of the nerves that caused a “storm” in the brain, allowing the patient to function normally. In 1981 Sperry won the Noble Prize in Physiology or Medicine for his split-brain experiment.
When the doctors cut the nerves they discovered something else — the person was able to live a normal life, but the one side of the brain was not able to communicate with the other so that one side didn’t know what the other side had learned.
Since the first bundle cutting, researchers have found that it is not necessary to severe the complete set of nerves to eliminate the epileptic’s seizures, but only a few select connections need to be cut.
Sperry and his colleagues observed how each area of the brain was able to work independently, and they each specialized in different tasks. The left side of the brain completes the analytical and verbal tasks, but speech is best from the right side. The right half takes care of music and space perception tasks like reading a map, or giving directions on how to get to your office from home. The right hemisphere puts emotion into your speech, but can only put together basic words and phrases. Without the help from the right hemisphere, you would be able to read the word “cat” for instance, but you wouldn’t be able to visualize what a cat was.
Split-brain patients gave researchers real insight into the operation of each side of the brain. For example: one of their patients, Paul S., “was more developed in language skills before the operation. This helped researchers to interview both sides of the brain after the operation. When asking the right side what Paul wanted to be, he said an automobile racer. When asking the left side he said he wanted to be a draftsman.”
One split-brain patient exhibited strange behavior involving his hands. His right hand tried to pull up his pants while the left hand tried to pull them down. Another patient argued with his wife, one side attacking her with his left hand and the right hand defending her.
Sperry did an experiment where he flashed a word so the right hemisphere of the brain would interpret the information. The patient wrote down the correct word with his left hand, but when asked what he wrote done the patient did not know. The right side of the brain was able to write down the information, but the left side had no idea what the right side did.
These experiments on split-brain patients certainly indicate that both sides of the brain are independent of each other, but each side has an area it specializes and is more dominant in than the other side. What they do know is that we need both sides of our brain to function normally, even if they are not connected.
About the author:
Ron White is a two-time U.S.A. Memory Champion and memory training expert. As a memory keynote speaker he travels the world to speak before large groups or small company seminars, demonstrating his memory skills and teaching others how to improve their memory, and how important a good memory is in all phases of your life. His CDs and memory products are also available online at BrainAthlete.com.
Split-Brain Behavior, by Marsha Vasiliadis : http://serendip.brynmawr.edu/bb/neuro/neuro00/web1/Vasiliadis.html
Nobel Prize.org — The Split Brain Experiments: http://www.nobelprize.org/educational/medicine/split-brain/background.html