Ch. 2 Split- Brain Research

-controls writing and movements of the right side of the body Write in the left margin: -controls writing and movements of the right side of the body -verbal tasks

-nonverbal, spatial and visual tasks Write in the right margin: -controls touch and the movement of the left side of the body -nonverbal, spatial and visual tasks

“Split-brain”- A surgical procedure where the corpus callosum is severed- causing the two hemispheres to function in isolation. -Used to treat severe cases of Epileptic seizures.

Each hemisphere is still able to learn after the split brain operation but one hemisphere has no idea about what the other hemisphere has experienced or learned. Today, new methods and technology in split brain operation make it possible to cut off only a tiny portion and not the whole of the corpus callosum of patients.

 The studies demonstrated that the left and right hemispheres are specialized in different tasks. The left side of the brain is normally specialized in taking care of the analytical and verbal tasks. The left side speaks much better than the right side, while the right half takes care of the space perception tasks and music, for example.

The right hemisphere is involved when you are making a map or giving directions on how to get to your home from the bus station. The right hemisphere can only produce rudimentary words and phrases, but contributes emotional context to language.

The final evidence for this, however, came from the famous studies carried out in the 1960s by Roger Sperry and his colleagues. The results of these studies later led to Roger Sperry being awarded the Nobel Prize in Physiology or Medicine in 1981. Sperry received the prize for his discoveries concerning the functional specialization of the cerebral hemispheres. With the help of so called "split brain" patients, he carried out experiments, and for the first time in history, knowledge about the left and right hemispheres was revealed.

"The great pleasure and feeling in my right brain is more than my left brain can find the words to tell you." Roger Sperry

Michael Gazzaniga, who did his graduate work in Sperry's laboratory, carried out the psychological tests on patients. The very first, a middle-aged World War II veteran, gave the surgeons a scare. He couldn't talk after the operation. But, happily, his speech returned a month later. Over the years, this loss of speech has not been typical at all. As a matter of fact, the second patient coming out of anesthesia complain, "I have a splitting headache!" And when his nurse asked him how well he could talk, he smiled and answered: "Peter Piper picked a peck of pickle peppers!" To the casual observer, the early split brain patients appeared perfectly normal. They could talk and read and had no problems recognizing the world about them. The seizures gone, they seemed happy, alert and healthy.

Then Gazzaniga made a startling discovery Then Gazzaniga made a startling discovery. If the patient held up something like a comb or a coffee cup in his left hand, he couldn't speak its name. Transferred to the right hand -- no trouble at all. The same happened with words. If Gazzaniga held up a card with a printed word like HOUSE visible only in the patient's left visual field, he couldn't read it. Yet the left eye was fine. But Gazzaniga knew that the left visual field flashes only to the right side of the brain. And when Gazzaniga put the HOUSE in the right field, guess what happened. The patient immediately recognized it.

Language: French physician, Paul Broca- -Research in 1860’s on stroke victims -believed language is controlled in the left hemisphere of the brain Broca’s Area: -essential to our ability to talk -found in the frontal lobe

Scientist Karl Wernicke- -continued Broca’s research a decade later. Wernicke’s Area: -located in the left side of the temporal lobe -crucial in processing and understanding what others are saying.

Over Simplifying the Point: Wernicke’s Area seems to be important for listening, and Broca’s area seems to be important for talking.

Hemispheric Theory Review your score from the chart. In your note packet is a list of “typical” descriptors for each hemisphere- Do you agree?