The science of my topic surrounds a part of the brain called the corpus callosum. The corpus callosum is a set of nerve fibers located between the two hemispheres of the brain and allows the two halves of the brain to communicate with each other. In 1939, the chief surgeon at the University of Rochester Medical Center, William Van Wagenen, performed a surgery on ten patients which cut their corpus callosum in hopes of treating epilepsy. He thought this would work after seeing an epilepsy patient stop having seizures after a cancerous tumor destroyed their corpus callosum. This surgery resulted in an obvious reduction in seizures in seven of the ten patients.
Through split brain patients and experiments done by other surgeons, much has been learned about what happens when the two sides of the brain cannot communicate with each other after developing with a functioning corpus callosum. Roger Sperry ran an experiment on split brain cats where he covered one eye of the cat while teaching them the difference between two shapes. When the eye was uncovered and the other eye was then blindfolded, the cats could no longer tell the difference between the shapes without relearning. This shows how in split brains, each side of the body works independently. Each hemisphere of the brain only controls half the body. The right hemisphere controls the left side of the body while the left hemisphere controls the right.
Sperry later worked with human subjects with the help of Michael Gazzaniga and Joseph Bogen. They performed a split brain surgery on William Jenkins, a WWII veteran that suffered from seizures, in 1962. After the surgery, they ran experiments on Jenkins. In one, a dot was in the center of a screen while another picture was shown to the left or right. If the photo was to the right, Jenkins said he saw it, but if it was on the left, he claimed to see nothing. When asked to point to the object on either side, he could. This showed only one side of the brain could communicate information through words in split brains. In addition, Gazzaniga found by working with a patient referred to as P.S. that the left brain made excuses for mistakes made by the right brain pointing to a photo when it would not make sense to instead of saying they did not know why they were pointing.
In another experiment, Jenkins had to arrange blocks with one hand. The right side of the brain is good with motor skills, and his left hand was, therefore, able to arrange blocks easily. Meanwhile, his right hand not only struggled, but his left hand would start helping subconsciously. The sides of the brain can disagree in split brain patients or get in the way of each other. For example, Jenkin’s left hand would undo what his right did when allowed to use both hands. This work won Gazzaniga and Sperry a Nobel Prize in 1981.
This is important to society because it challenges ideas of individualism and self. If the two halves of the brain can work separately, it questions whether a person can be one or two conscious beings in one body. One way the theory of two beings in one body is being tested is through the current research of Michael Miller. In his experiments, the split brain patient is told a character trait while the word “me” is on one side of a screen and “not me” on the other side to the left and right. Then, they must point to the screen when a word corresponding to how they were told they are appears. If each hand points to opposing words, that proves each hemisphere in split brains can have its own unique emotional state. However, this research is ongoing. Split brains also build on Sigmund Freud’s idea that psychologically, humans have three parts fighting within them (the ego, the super-ego, and the ID). Multiple personalities in one body can also be seen in stories, such as Dr. Jekyll and Mr. Hyde, or an angel on one shoulder and a devil on the other.
As far as myself, I was drawn to this topic after watching a YouTube video, and I am a YouTuber. I also like being able to debate things that have no clear answer, like split brains being either one person still or two beings. I think it would be cool to imagine two beings in the brain, but that also makes little sense. I have been raised with the idea people can change over time, and we are multiple people over the course of a lifetime, but not two people at any one time. I suggest people stay open to any possibilities science can later present, but not worry about split brains too much right now.
I do not think the original video I watched was reliable since CGP Grey does not list their sources or even give their own name. However, I was able to find my own reliable sources to backup the video. The Nobel Prize’s website talks about split brains since Gazzaniga and Sperry shared a Nobel Prize. I was also able to find a large amount of information from an article published in The Atlantic. I found information on Sigmund Freud’s theory on a site written by a college professor of psychology. I learned more about Wagenen from The Society of Neurological Surgeons. While I found this topic from a questionable source, I was able to verify the science of split brains with trustworthy websites.
References
The Split Brain Experiments. (n.d.). Retrieved December 17, 2016, from https://www.nobelprize.org/educational/medicine/split-brain/background.html
Smith, E. E. (n.d.). One Head, Two Brains. Retrieved December 17, 2016, from http://www.theatlantic.com/health/archive/2015/07/split-brain-research-sperry-gazzaniga/399290/
William P. Van Wagenen, MD. (n.d.). Retrieved December 17, 2016, from https://www.societyns.org/society/bio.aspx?MemberID=99178
McLeod, S. (n.d.). Id, Ego and Superego. Retrieved December 17, 2016, from http://www.simplypsychology.org/psyche.html
You Are Two. (n.d.). Retrieved December 17, 2016, from https://www.youtube.com/watch?v=wfYbgdo8e-8
