While split-brain patients could be manipulated into displaying two independent cognitive styles, the underlying opinions, memories and emotions were the same. This can be explained anatomically. There are deeper structures of the brain that are critical to emotion and physiological regulation that remain connected. Split brains, actually, are not really split into two but instead form a Y. The fact that basic responses (such as the fear-conditioned responses like the heart rate increase to a visual conditioned stimulus) do cross from one hemisphere to the other even when the corpus callosum has been cut, showing that it crosses in lower pathways in the brain, might indicate the evolution of human consciousness.

s, and later proceeded to study monkeys. In nineteen sixty-one the first human patient was subject to this new procedure. The surgery worked well as a cure for patients who suffered from severe epilepsy and did not respond to anti-epileptic drugs. It was soon realized that patients who had a commissurotomy had some interesting difficulties. Patients were not able to communicate information from one hemisphere to the other, almost as thought now had two distinct separate brains. Several experiments were done to test perception in the "split-brain" patients. In one experiment, a word (for example"fork") was flashed so only the right hemisphere could receive the information. The patient would not be able to say what the word was. However, if the subjet was asked to write what he saw his left hand would begin to write the word "fork". If asked what he had written, the patient would have no idea. He would know that he had written something, because he could feel his hand going through the motion. Yet he could not tell the observers what the word was. Because there was no longer a connection between the two hemispheres, information presented to the right half of the brain can not convey this information to the left half. Interestingly enough, the centers for speech interpretation and production are located in the left hemisphere

Some topics in this essay:
PJ Vogel, Ronald Myers, Human Brain, Jekyll Hyde, split-brain patients, left hemisphere, left hand, corpus callosum, noted patients, human brain, procedure involves, surgical procedure, jekyll-hyde effect, trying pull,