In this meme, I am showing the common misperception that people have when learning about split-brained patients. Often, we are confused by this concept of being split-brained which causes us to jump to conclusions. We instantly see a brain that is a bit abnormal compared to what we usually see and assume that this abnormality can be applied to us. We forget that in order to relate to the different concepts of being split-brained, you must have a severed corpus callosum. Today, the surgery that had previously caused this severing of the corpus callosum is no longer done. This surgery was done in the past to try and treat epilepsy, but after seeing all of the different side effects that came along with the surgery and how it affected the brain, this surgery is no longer conducted.
As we know and have learned throughout this course, our left hand and left visual field are controlled by our right hemisphere. With that being said, our right hand and right visual field are controlled by our left hemisphere. When we conduct an experiment with a split-brain patient, we use different combinations of their left and right hands with their left and right visual fields. By alternating these factors, we are able to see what sorts of things that split-brain patients can and can’t do without the use of their corpus callosum. The corpus callosum is what passes information between the left and right hemispheres, so without this link the left and right hemispheres are much more limited in what they can accomplish. The left hemisphere and right hemisphere are now independently responsible for what they produce, rather than being able to access information from both sides and working together to help brain functioning.
While conducting the experiment, we found quite a bit of different data. When the left hand and left visual field are paired, the split-brain patient does not know what word they saw, but they are able to retrieve the object. When the left hand and right visual field are paired, the split-brain patient is able to see the word, but unable to retrieve the object. When the right hand and left visual field are paired, the split brain-patient did not know what word they saw and were unable to retrieve the object. Finally, when the right hand and right visual field are paired, the split-brain patient is able to both see the word and retrieve the object.
When reviewing this data, we are able to notice some key points about the left and right hemispheres. We notice that when the right hemisphere is working on its own by using the left hand and left visual field, they are unable to remember what they saw. This is the opposite for when the left hemisphere works on its own by using the right hand and right visual field. This is because the left hemisphere is superior in dealing with language. You could expect the right hemisphere to be better at grabbing or touching what they saw, even though they couldn’t recall seeing it. The split-brain patient could even draw the word that they saw, but this may be difficult if the patient is usually right-handed.
In conclusion, I made this meme to address the issue we see with people who learn about split-brain patients. We tend to believe that these things can happen to our brain, when in reality our corpus callosum is intact. Thankfully, this surgery can no longer be conducted, so we do not need to worry about our corpus callosum being severed and halting the flow of information between our two hemispheres.
Cognitive Neuroscience Class Lecture