User:Birdie2324/Split-brain

The corpus callosum, highlighted in red, is the main neural pathway between the two hemispheres.

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Corpus callosotomy

A corpus callosotomy usually involves the cutting of the front part of the corpus callosum in order to reduce the frequency and intensity of the seizures. In cases where the seizures continue in frequency and severity, a second surgery may be needed. The concept of the split brain raises questions about the level of consciousness left. This makes first person accounts difficult to asses as researchers don't know if the consciousness was split as well.

Although much of the inter-hemispheric transfer occurs at the corpus callosum, there are trace amounts of transfer via commissural pathways, such as the anterior commissure, posterior commissure, habenular commissure, and the hippocampal commissure.

Memory

It is known that the right and the left hemisphere have different functions when it comes to memory. The right hemisphere is better at recognizing objects and faces, recalling knowledge that the individual has already learned, or recalling images already seen. The left hemisphere is better at mental manipulation, language production, and semantic priming but was more susceptible to memory confusion than the right hemisphere. The main issue for individuals that have undergone a callosotomy is that because the function of memory is split into two major systems, the individual is more likely to become confused between knowledge they already know and information that they have only inferred.

In tests, memory in either hemisphere of split-brained patients is generally lower than normal, though better than in patients with amnesia, suggesting that the forebrain commissures are important for the formation of some kinds of memory. This suggests that posterior callosal sections that include the hippocampal commissures cause a mild memory deficit (in standardized free-field testing) involving recognition. This makes first person accounts hard to consider and assess as scientists don't know if the consciousness was split as well.

Surgery procedure

The surgical operation to produce this condition (corpucallosotomy) involves transection of the corpus callosum, and is usually a last resort to treat refractory epilepsy. To lower the degree and ferocity of epileptic convulsions, partial callosotomies are first done; if these are unsuccessful, a callosotomy is next carried out to reduce the risk of unintentional bodily harm. Epilepsy is first managed with medications rather than callosotomies. Neuropsychological evaluations following surgery are frequently carried out.

Lifestyle

What a normal brain looks like compared to someone who has a split brain

When split-brain patients are shown an image only in the left half of each eye's visual field, they cannot vocally name what they have seen. This is because the image seen in the left visual field is sent only to the right side of the brain (see optic tract), and most people's speech-control center is on the left side of the brain. Communication between the two sides is inhibited, so the patient cannot say out loud the name of that which the right side of the brain is seeing. A similar effect occurs if a split-brain patient touches an object with only the left hand while receiving no visual cues in the right visual field; the patient will be unable to name the object, as each cerebral hemisphere of the primary somatosensory cortex only contains a tactile representation of the opposite side of the body. If the speech-control center is on the right side of the brain, the same effect can be achieved by presenting the image or object to only the right visual field or hand.

The same effect occurs for visual pairs and reasoning. For example, a patient with split brain is shown a picture of a chicken foot and a snowy field in separate visual fields and asked to choose from a list of words the best association with the pictures. The patient would choose a chicken to associate with the chicken foot and a shovel to associate with the snow; however, when asked to reason why the patient chose the shovel, the response would relate to the chicken (e.g. "the shovel is for cleaning out the chicken coop").

Roger Sperry and Michael Gazzaniga went on to conduct other tests to shed light on the language processing abilities of the right hemisphere as well as auditory and emotional reactions as well. The significance of the findings of these tests by Sperry and Gazzaniga was extremely telling and important to the psychology world. Their findings showed that the two halves of the brain have numerous functions and specialized skills. They concluded that each hemisphere has its own functions. The left hemisphere is thought to be better at writing, speaking, mathematical calculation, reading, and is the primary area for language. The right hemisphere is seen to possess capabilities for problem solving, recognizing faces, symbolic reasoning, art, and spatial relationships.

Seizures damages

Usually used as a last option to treat resistant epilepsy, the surgical procedure known as a corpus callosotomy includes transection of the corpus callosum. To reduce the danger of accidental damage to the body by lessening the intensity and violence of epileptic seizures, partial callosotomies are first attempted. If this procedure is unsuccessful, a total callosotomy is next carried out.