Split Brain Consciousness

"It started when Paul awoke from surgery. He was immediately able to understand many kinds of language in his right hemisphere. This ability was most unusual; all other patients had been able to comprehend language only with their dominant left hemisphere. Only patients SB and NG in the California series had shown evidence of right-hemisphere language, and then only sometime after the operation. Moreover, Paul's language was a richer kind. His right hemisphere could not only understand the meanings of nouns (a skill the California patients had finally achieved), but he could also carry out verbal commands presented exclusively to his mute right half-brain. Even more startling was Paul's ability to write answers to questions asked of his right half-brain. Instead of wondering whether or not Paul's right hemisphere was sufficiently powerful to be dubbed conscious, we were now in a position to ask Paul's right side about its views on matters of friendship, love, hate, and aspirations. 'Who are you?' He writes: 'Paul.' 'Where are you?' He writes: 'Vermont.' 'What do you want to be?' He writes: 'Automobile racer.' When the left hemisphere was asked this same question, he wrote (with his right hand), 'Draftsman.'"(1)

In those of us with healthy, intact brains, information presented to our right hemisphere is quickly sent to our left hemisphere. What happens when the right and left hemispheres of your brain can no longer communicate? This is what a spit-brain patient experiences, and in talking with one of these patients you probably wouldn't notice anything unusual. The patient appears completely intact and unchanged when observed by family and friends. If there are no other brain illnesses present, then cognitive functions are usually within the normal range. It is only when specific tests are administered do the symptoms of disconnection emerge.

This web page explores the function of the brain's hemispheres, how information is shared between them via the largest of the interhemispheric commissures, and what symptoms result as a consequence of a split brain operation in which the commissure is severed.

What is a Split Brain Operation?

Hemispheric Specialization

How the Brain and Body Communicate

History of the Split Brain

Current "Stuff"

Behavior of Split Brain Patients



If you have any questions or comments please feel free to contact any of us, asenders@macalester.edu, cgarman@macalester.edu, eanderson@macalester.edu, and tbjohnson@macalester.edu