Monday, March 8, 2010

Phantom Limb

I never fully thought about the complexity and abilities the brain holds. Vilayanur Ramachandran is a neurologist that explores many fields in behavioral neurology including the "Phantom Limb" syndrome which is completely fascinating. In some cases, when a patient has a body limb amputated (or even organs removed) they can still feel the sensation of the missing body part as if it is still there - so even though the eye can see that there is nothing there and the brain knows it is not there, a part of the brain forces the body to feel as if it is still there. In a fair amount of cases, some patients has complained about having excruciating pain from a clenching fist coming from their phantom arm. This is an odd phenomenon because since it is so conflicting. How can one organ of the body, tell us two different things? Ramachandran has found that if you create a mirror box and place both the existing hand and phantom hand inside and look at the reflection of the real hand moving about as if it was the phantom hand, the brain sends signals causing the sensation of the phantom hand moving - the excruciating pain of the previously paralyzed clench fist has been released. In these cases, it occurs when the the nerve of the limb is damaged and results in a "learned paralysis" causing the brain feel that their phantom limb is paralyzed and unable to move it. I find this extremely fascinating because of the complexity of the signals and how one signal can override others; how there are other routes in the brain to get around a direct connection that has been lost.

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