Mind and Brain
Learning about mind and brain is one of the most interesting things I have found in my life. The fact that everything we are and everything we do is controlled by a biological organ in our skull is so fascinating and at the same time hard to understand. We sometimes get so used to it that we forget to ask questions about its most simple tasks. We still do not know the answer to most of our questions about mind and brain and cognitive thoughts and behaviors. A wise person once said that neuroscience stands where physics was ~100 years ago. This sounds very true to me. One hundred years ago marked the era that simplest particles like proton and neutron were just discovered or about to be discovered (proton was studied and named by Rutherford sometimes between 1917-1920; neutron was discovered by Chadwick in 1932) and Einstein had just come up with his general theory of relativity (which described how gravity really worked!).
Last summer, I read a (relatively old) neuroscience book by Dr. Ramachandran entitled “Phantoms in the Brain”. There are several interesting case studies in this book, among which I have been fascinated by the weird behavior of the brain in “Arthur’s case”, so I decided to bring it up in my class and ask my students to place themselves in Dr. Ramachandran’s shoes and try to understand what was going on with Arthur’s brain. The syndrome discussed in Arthur’s case is called Capgras syndrome (or delusion) or imposter syndrome. Arthur was a 30-year-old guy who suffered from imposter syndrome after a car accident: he thought his parents were imposters and that was the only symptom that arose after the accident. Dr. Ramachandran visited Arthur for a long time and finally discovered the reason.
Here is the case in more details: Arthur thinks his parents are imposters. He even wonders why anyone would want to pretend to be his parents. He claims they are not his real parents only when he sees them face to face. He has no problem when hearing them on the phone; they seem real to him while being heard. With this information, what would be your first guess what could have gone wrong in Arthur’s brain?
You might think maybe his visual recognition (the part of temporal lobes that specializes in face and object recognition: the “what pathway”) is damaged. But he recognizes people from past, such as elementary school friends and ex-girlfriend. He also recognizes different objects. So you might ask how about his feelings and emotions? Are they damaged? The answer is no! He laughs and cries, he has a sense of humor and he makes jokes. He even shows emotions when talking to his parents on the phone! But how about when he sees his parents? One can use a Galvanic Skin Response (GSR), like what they use in the famous lie detector test to see if he has reactions to emotions when he sees his parents. Doctors used GSR to see if his level increases when he sees e.g. his mom. The result was that Arthur’s skin conductance did not change in this experiment compared to the control group. So now what would you think the problem would be if neither Arthur’s visual recognition is damaged nor his limbic system, his amygdala and parts related to generating emotion? What could be damaged then?
If neither of these two regions of the brain are damaged maybe they are disconnected, so Arthur cannot generate emotions when seeing his loved ones. Normally the face recognition areas relay information to the limbic system, found deep in the middle of the brain, which can help to generate emotional responses to particular faces. In Arthur’s case this does not happen due to the disconnection between the two areas. So he sees two people identical to his parents but he does not feel anything seeing them, so he concludes they are imposters. However, there are separate pathways from the auditory cortex, the hearing areas of the temporal lobes to the amygdala, therefore Arthur generates emotions while hearing his parents but not in case of seeing them.