Split Brain Project Summary

This summer I had the opportunity to explore a topic that I became interested in during my freshman year at William and Mary, which is the corpus callosotomy, more commonly known as split brain surgery. This is when the brain is surgically cut into two halves. In my freshman seminar, it was briefly mentioned as a rare option for treating patients with epilepsy, and I was curious to find out more about how this procedure works in the brain and how it can put a stop to debilitating seizures.

First I did some research to find out what exactly is happening in the brain that causes seizures, and I learned that it is a storm of abnormal electrical signaling in the brain that is displayed as physical convulsing or prolonged staring in one direction with complete loss of the ability to respond. Surgical techniques are used to take out the part of the brain that is initiating the faulty signals, or in the case of the corpus callosotomy, it severs the two hemispheres of the brain to keep the signals from passing between the two hemispheres.

To gain a more personal perspective on the topic, I talked to one of my cousins, whose son Joshua suffered from constant seizures for many years. When they became too frequent and violent for medication to contain, his doctor’s decided to perform a Temporoparietooccipital (TPO) resection. This was the removal of the temporal, occipital, and parietal lobes of the left hemisphere of the brain, which stopped the abnormal electrical signaling in those parts of his brain that were causing the seizures. Not only did I learn a lot about the science behind what his doctor’s were doing, but I got to hear how Joshua’s epilepsy took a toll on his and his mother’s lives, and how much his quality of life has improved since the operation. This was incredibly eye opening and gave me a new appreciation for modern medicine.

I then began my research on split-brain syndrome, which is the neurological effects that the corpus callosotomy has on the patient. This is the part that originally struck me as interesting, so I was excited to find out more. The intrigue in this topic revolves around the key idea that the brain only has a language processing center in the left hemisphere. In the average human, you would never notice this, but in a split brain patient, you can do certain tests with this. If you flash an image to the left eye of a split brain patient, that image will be transferred, like normal, to the right hemisphere of the brain. But if you ask the patient to tell you what they saw, they will not be able to. This is because without the two hemispheres being connected, the image cannot be sent to the language center in the left hemisphere, so the brain does not know what to say. In any other normal human, the image would simply be sent from the right brain to the left brain, and the word would be spoken. But what is really interesting, is if you then ask the split brain patient to draw what they saw with their left hand, they would be able to draw the image they were shown. This is because the left hand is controlled by the right brain, so it had the necessary information to identify the image. I also learned about how certain tasks are hard or impossible to learn for split-brain patients due to their inability of the two hemispheres to coordinate and work together.

I then looked back at the main points in the history of split brain research, including famous patients and experiments throughout the years. The charge was led by scientists Roger Sperry and Michael Gazzaniga, and the first corpus callosotomy was performed in the 1940’s. While the operation was being used to treat epilepsy, it became vital to learning more about how the brain is really two separate halves that talk to each other yet work independently. However in more recent times, better treatments for seizures have been invented and the corpus callosotomy is less common, so research on the topic has slowed down.

To go a little further, I also researched the procedure itself to see what exactly the surgeons are doing while the patient is on the table. This was incredibly interesting, as I have very little knowledge of how medical practices and procedures. From this I gathered that a patient can have a complete or partial callosotomy, which is based on how much of the corpus callosum is severed. In some cases, only the anterior portion needs to be cut.

I have thoroughly enjoyed my time exploring this intriguing topic, particularly the personal perspective I received from my cousin. This project has greatly heightened my interest in neuroscience and the medical field, and I plan to continue to broaden my knowledge on split brain surgery and similar topics in the future.


  1. sdevignierawad says:

    I think this project sounds absolutely fascinating, and it was really interesting to read about all of the research you did for it. I had never heard of this procedure before reading about your project, but it almost seems like something out of a science fiction movie that doctors can cut off communication between the two sides of your brain. The personal connection you had to the project made it even more well-rounded, and brought a more emotional side to the story. I am especially impressed with how much work was put into the project, and it really seems like you had a passion for the subject matter. All in all, this was a great project to read up on and I hope you had a great time doing it!


  2. What an interesting topic! I remember learning about the split brain surgery in Intro to Natural Psych.

    I had no idea that the surgery has been performed on patients since the 1940s. It seems like such an advanced surgery for the time. I mean in the 40s people still suffered from polio!

    I would love to hear more about your cousin’s experience after the surgery. It seems like having a piece of your brain removed would come with serious complications, but I’m glad that his overall quality of life has increased.

    Nice job on your project!

  3. Hello! I really enjoyed reading about your fascinating topic. Not going to lie, I have very little knowledge when it comes to the functions of our right and left sides of the brain. But I am curious if this line of research has any implications in treating mental illness as well. With people diagnosed with anxiety, there is no gray area. It is always black and white. When in reality, life is usually within that grey area. Do you think this has something to do with one side of the brain overpowering the other? If so, I wonder what implications this could have for other mental illness. Or maybe I’m completely off track and this has no relationship at all:) Curious about your thoughts….