Cognition

In a short but interesting interview in Walk the Talk by Shekhar Gupta, Dr V S Ramchandran talks about the rapid growth in comprehending the workings of human mind. Here's an excerpt:

What is your book Phantoms of the Brain about?

If you close your eyes, you have a very vivid image of your body parts—it’s called your body image. When you amputate somebody’s arm, the astonishing thing is that even after the operation the patient continues to vividly feel the presence of that arm. He himself is very surprised by this—he’s not stupid, he knows that his arm has been amputated. But he says, You’ve removed the arm, I don’t see an arm, but I vividly feel my fingers, my wrist, my elbow. This is called a phantom arm. It’s important clinically because many people feel excruciating pain in this phantom arm. Chronic pain in a real arm is hard enough to treat; how do you treat a patient who has pain in a non-existent arm?

It turns out that there’s a complete map of the body surface on the surface of the brain. When you amputate a person’s arm, a gap remains, corresponding to the hand, but which doesn’t receive any signals. Instead, the signals from the face invade that territory. It shows that there’s a great deal of malleability of connections in the brain—what we call plasticity. People didn’t realise it before we’d done that. That was the breakthrough. When you amputate the arm and you touch the patient’s face, the patient says, Oh, you’re touching my fingers. It’s a very simple clinical observation, but we said that the reason this happens is because the signal is now going to the wrong part of the brain. There’s been a cross-wiring, and it’s now invaded the vacated territory corresponding to the missing arm. This happens astonishingly fast, in clinical terms. In a couple of weeks, the face skin starts sending its sensory input to a new brain area. It’s radical because it shows that brain maps can change over distances of seven centimetres, even in the adult brain, challenging the clinical dogma that new connections cannot form in the adult brain.

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Going back to metaphor, it’s a big question. When Shakespeare says, It is the east and Juliet is the sun; when Tagore says of the Taj, It is a teardrop on the cheek of time—how do these people do it? Can you begin to approach this as a neuroscientist?

Another fascinating thing for me is human ability to spot, create and understand humor and humorous situations. What happens in the human brain, when someone says "This is funny !" And why does good laughter feel good ?