I missed class last Monday, and while I know you watched a movie about Ramachandran I am not sure what one. So, I just chose one that happened to be “Ramachandran on your mind”. In it he talked about how the brain processes visual information. He was explaining how you can learn about how the brain processes visual information by studying patients who have very specific damage to particular parts of the brain. If the damage is limited to specific regions than it gives you an opportunity to see what that specific area contributes to processing of information.
He gave three examples. The first was of patients who have damage to the fusiform gyrus, a specific area in the temporal lobes. These patients have a disorder called Capgras Syndrom. It’s really weird because they can’t identify faces. So they look at someone very familiar but can’t tell you who it is. No, what’s really remarkable is these patients don’t have a memory problem; they can identify the same person using other senses. For example if they hear their voice (hearing) or if the person wears a specific perfume (sense of smell), or if they have a distinctive rhythm to their walk (hearing).
The second example is Capgras Delusion. These patients have damage to a fiber pathway that comes out of the fusiform gyrus. Because the fusiform gyrus is ok they can identify faces but what happens is the patient will say, “that looks just like whoever, but its not them, its an imposter.” So this fiber pathway links the parts of the brain that recognize familiar faces with the part of the brain that links emotion to what you are seeing. Because this link is broken the patient knows the face looks like someone they know, but since that face doesn’t cause them to have an emotional response they think it can’t be that person.
The third example—interestingly was on an episode of House—is phantom limb. About half of the people who have a limb amputated will feel extreme pain and it feels like the pain is in the missing limb with the sensation that they can’t move the missing limb. Really weird. Well, what this Ramachandran figured out was that these patients all had paralysis for some amount of time before the limb was cut off. What he thought might be happening was that during the time before the limb was cut off, they learned that the limb couldn’t move, then when it was cut off, their brains still thought the limb was paralyzed and stuck in a very painful position. So what he did was see if he could trick the brain to think differently. So what he did was have the patient stick their good arm into a box with a mirror so when the patient looked in it looked like there were two arms (a right and left). Then he had them watch as they moved their real limb and what the brain saw was that the phantom limb was moving too. Well this experience taught the brain that the missing limb actually could move, and when the brain learned this, the pain from thinking it was paralyzed in a painful position went away!
Personally, I was really interested in Capgras Syndrom because I have always had a hard time recognizing people. Naturally, I don’t suffer from anything as extreme as Capgras Syndrom, and I don’t have damage to my fusiform gyrus that I know of. What I wonder, is weather or not the people with Capgras Syndrom get heightened senses in the same way blind people do. For example, while I have problems recognizing people’s faces, I also could never identify someone by smell in the same way a person suffering from Capgras Syndrom could. I looked into it however, and found nothing that could answer my question, and as Ramachandran explains, the mind is a crazy thing that we still don’t really understand.