Amputees sometimes experience phantom limb sensations, feeling pain, itching or other impulses coming from limbs that no longer exist. Neuroscientist Vilayanur S. Ramachandran worked with patients who had so-called phantom limbs, including Tom, a man who had lost one of his arms.
Ramachandran discovered that if he stroked Tom’s face, Tom felt like his missing fingers were also being touched. Each part of the body is represented by a different region of the somatosensory cortex, and, as it happens, the region for the hand is adjacent to the region for the face. The neuroscientist deduced that a remarkable change had taken place in Tom’s somatosensory cortex.