Split-Brain Syndrome and Kim Peek Quiz

Split-Brain Syndrome: Understanding the Condition and its Implications

• Split-brain or callosal syndrome is a type of disconnection syndrome caused by severing the corpus callosum connecting the two hemispheres of the brain.

• Corpus callosotomy is a surgical operation that involves transection of the corpus callosum and is usually performed as a last resort to treat refractory epilepsy.

• After the right and left brain are separated, each hemisphere will have its own separate perception, concepts, and impulses to act.

• Split-brain patients cannot vocally name what they have seen when an image is shown only in the left half of each eye's visual field.

• Split-brain patients are unable to name an object if it is touched with only the left hand while receiving no visual cues in the right visual field.

• Early anatomists identified the corpus callosum as a structure holding together the two halves of the brain, while in 1892, Joseph Jules Dejerine reported symptoms in a person who had destruction of part of the corpus callosum.

• Roger Sperry and his colleagues pioneered research showing that the right hemisphere can allow people to read, understand speech, and say some simple words.

• Sperry's research showed that the disconnected right hemisphere is superior to the disconnected left hemisphere in allowing people to understand spatial information, music, and emotions, whereas the disconnected left hemisphere is superior in allowing analytical thinking, talking, reading, and understanding speech.

• Sperry and Gazzaniga's research showed that each hemisphere of the brain has its own functions, with the left hemisphere being better at writing, speaking, mathematical calculation, reading, and primary language, while the right hemisphere possesses capabilities for problem-solving, recognizing faces, symbolic reasoning, art, and spatial relationships.

• The corpus callosum, which carries signals between the left-brain hemisphere and the right-brain hemisphere, is essential for communication and coordination between the two hemispheres of the cerebral cortex.

• The right hemisphere of the cortex excels at nonverbal and spatial tasks, whereas the left hemisphere is more dominant in verbal tasks, such as speaking and writing.

• The corpus callosum is a structure in the brain along the longitudinal fissure that facilitates much of the communication between the two hemispheres, but there is evidence that it may also have some inhibitory functions.Split-Brain Patients: Understanding Interhemispheric Communication

• The splenium transfers visual information and there is a redundancy gain in simple reaction time in split-brained patients.

• Functional deficiencies are common after a stroke or brain injury, and recovery is generally thought not to continue past 6 months.

• Little functional plasticity is observed in partial and complete callosotomies on adults, but more plasticity can be seen in infant patients receiving a hemispherectomy.

• Corpus callosotomy is a surgical procedure that sections the corpus callosum, resulting in either the partial or complete disconnection between the two hemispheres.

• The right and left hemisphere have different functions when it comes to memory, which can lead to confusion in split-brained patients.

• Split-brained patients behave in a coordinated, purposeful and consistent manner, despite the independent, parallel, usually different and occasionally conflicting processing of the same information from the environment by the two disconnected hemispheres.

• Experiments on covert orienting of spatial attention using the Posner paradigm confirm the existence of two different attentional systems in the two hemispheres.

• Patient WJ was the first patient to undergo a full corpus callosotomy in 1962, and his operation was a success.

• Patient JW showed that the left hemisphere was highly accurate in performing simple addition, subtraction, multiplication and division, while the right hemisphere was at chance for most.

• Patient VP had callosal sparing and showed no evidence for transfer of colour, shape or size, but there was evidence for transfer of word information.

• Kim Peek, a savant, was born without a corpus callosum, an anterior commissure, or a posterior commissure, and was able to memorize over 9,000 books and information from approximately 15 subject areas.

• Peek had developed language areas in both hemispheres, something very uncommon in split-brain patients, which led to his extremely fast reading ability.The Life and Brain of Kim Peek

• Kim Peek was born with macrocephaly and suffered from developmental disabilities.

• Despite his disabilities, Peek had an incredible memory and could memorize books, phone books, and maps.

• Peek was not diagnosed with savant syndrome, but his abilities were similar to those of savants.

• Peek's brain was studied by scientists, and they discovered that he had a lack of connection between the left and right hemispheres.

• Peek's lack of connection between hemispheres was due to a failure in the development of the corpus callosum, which normally connects the two.

• Peek's lack of corpus callosum allowed each hemisphere to function independently, leading to his extraordinary memory and other abilities.

• Peek's brain was also found to have abnormalities in other areas, such as the cerebellum and the hippocampus.

• Peek's life and abilities were the inspiration for the character Raymond Babbitt in the movie Rain Man.

• Peek was not always able to perform tasks that required abstract thinking or problem-solving.

• Peek's abilities were not due to photographic memory, but rather a unique way of processing and storing information in his brain.

• Peek's life and brain have been studied extensively, providing insights into the functioning of the brain and the role of the corpus callosum.

• Peek passed away in 2009 at the age of 58.