Experiment Gives Phantom Limb Syndrome To People Who Have All Of Their Limbs
A simple illusion caused subjects to mentally process an extra hand. You've probably heard of phantom limb syndrome. Because of odd wiring in the brain, a majority of amputees get the (frequently painful) sensation of having a limb, even after it's gone. But a team has shown that you don't have to be an amputee to have this feeling. Neuroscientists at the Karolinska Institutet in Sweden created the illusion of a phantom limb in non-amputees like this. First, they had subjects sit down and place their arm behind a screen, so it was out of view. Next, behind the screen, the scientists tickled the unseen hand with a paintbrush. While they did that, the scientists waved a second paintbrush in front of the subjects, in full view. The two paintbrushes--the invisible one tickling the hand and the other just brushing the air in front of the subject--made the same movements. The scientists...