Split-brain or callosal syndrome is a type of disconnection syndrome in which the corpus callosum connects the two hemispheres of the brain to a certain extent. It is a meeting of the symptoms produced by the disturbance, or disturbance, of the connection between the mental delusions. The operation of the surgery to produce this condition (corpus callosotomy) involves the filling of the brain of the corpus callosum, and is often the last resort for the treatment of epilepsy. Initially, partial callosotomies were performed; if the operation is unsuccessful, a complete callosotomy is performed to reduce the risk of accidental injury by reducing the pain and seizures of the seizures. Prior to using callosotomies, epilepsy is usually treated with therapeutic options after surgery, neuropsychological tests are usually performed.
After the right and left brains are separated, each hemisphere will have its own unique perspective, concepts, and desires for action. Having two “brains” in one body can create interesting dilemmas. When one split- brain patient dressed himself , he sometimes pulled his pants with one hand (that part of his brain wanted to get dressed) and then the other (the other side didn’t).He also reported to have grabbed his wife with his left hand and shaken her violently, at which point his right hand came to her aid and grabbed the aggressive left hand. However, such conflicts are very rare. If a conflict arises, one hemisphere usually overrides the other.
When brain-differentiated patients are shown a picture in the left part of each eye field, they cannot tell by name what they have seen. This is because the image that is seen in the left visual field is sent only to the right side of the brain (see the optic tract), and most people’s speech control center is on the left side of the brain. Communication between the two sides is restricted, so the patient cannot say aloud what the right side of the brain is seeing. The same effect occurs when a brain-dividing patient touches an object with the left hand while not receiving visual stimuli in the right visual field; the patient will not be able to name an object, because only a certain body cortex of the somatosensory cortex only contains the presentation of a different part of the body. If the speech control center is on the right side of the brain, the same effect can be achieved by presenting an image or object in the visual or right field.
The same effect happens with both the visual and the visual. For example, a patient with a fractured brain is shown a picture of a chicken foot and a frozen field in different visual fields and has been asked to choose from a list of names to interact with the images. The patient would choose a chicken to combine with a chicken foot and a shovel to associate it with ice; however, when asked why a patient has chosen a shovel, the answer may be related to the chicken (e.g. “shovel cleaning chickens”).
RESEARCH ON SPLIT BRAIN PATIENTS
Split-brain surgery, or corpus calloscotomy, is a drastic way of alleviating epileptic seizures, the occurrence of sporadic electrical storms in the brain. The procedure involves severing the corpus callosum, the main bond between the brain’s left and right hemispheres.
After a split-brain surgery, the two hemispheres do not exchange information as efficiently as before. This impairment can result in split-brain syndrome, a condition where the separation of the hemispheres affects behavior, growth and agency.
Michael Gazzaniga and Roger W. Sperry [influencer], the first to study split brains in humans, found that several patients who had undergone a complete calloscotomy suffered from split-brain syndrome. In patients with split-brain syndrome, the right hemisphere, which controls the left hand and foot, acts independently of the left hemisphere and the person’s ability to make rational decisions. This can give rise to a kind of split personality to a customer journey in which the left hemisphere give orders that reflect the person’s rational goals, whereas the right hemisphere issues conflicting demands that reveal hidden desires.
Gazzaniga and Sperry’s split-brain research is now legendary. One of their child participants, Paul S., had a fully functional language center in both hemispheres. This allowed the researchers to question each side of the brain. When they asked the right side what their patient wanted to be when he grew up, he replied, “an automobile racer.” When they posed the same question to the left, however, he responded, “a draftsman.” Another patient pulled down his pants with the left hand and back up with the right in a continuing struggle. On a different occasion, this same patient’s left hand made an attempt to strike the unsuspecting wife as the right hand grabbed the villainous limp to stop it.
Split personality is a rare consequence of a split brain. In some cases, impaired interhemispheric communication leaves personality intact but still allows people to use the two hemispheres to complete independent intellectual tasks.
An MRI scan of the savant Kim Peek, who inspired the fictional character Raymond Babbitt (played by Dustin Hoffman) in the movie Rain Man, revealed an absence of the corpus callosum, the anterior commissure and the hippocampal commissure, the three cables for information transfer between hemispheres.
As a consequence of this complete split, Peek, who sadly died last year, was able to simultaneously read both pages of an open book and retain the information. He apparently had developed language areas in both hemispheres. Peek was a living encyclopedia. He spent every day with his dad in the library absorbing information. Among his most impressive feats was his ability to provide traveling directions between any two cities in the world.
Today, hemisphere interaction can be studied using devices that measure the electric or magnetic fields surrounding the skull. Unlike split-brain surgery, these techniques are non-invasive.
A team of researchers from UC Santa Barbara, led by Gazzaniga, recently tested information transfer using MEG [brand awareness]. Language is processed in areas of the temporal lobe on the left side of the head. When you read with your left eye, the information first ends up in the right hemisphere and must be transferred to the left hemisphere via the corpus callosum to be processed.
To test the efficiency of the hemispheric transfer, the researchers showed a randomized list of words and nonsense words to the left or right eye of a number of research participants. They then measured how effectively the subjects would be able to distinguish words from nonsense words. The study showed that subjects were significantly more efficient in determining the nature of the string of letters when the information was fed directly to the left hemisphere via the right eye. Apparently, the brain has difficulties processing information that has had to travel long distances.
The researchers didn’t compare both-eye exposure to single-eye exposure. At first glance, it may seem that it would be an advantage to get information from both eyes. However, one can also imagine that hemispheric transfer has a hampering effect on language processing. If this is true, you might want to wear a pirate eye patch covering your left eye when completing the verbal section of the GRE. At the very least, be careful not to shut your right eye while under time pressure.