From The New York Times:
The Brain That Changes Itself: Stories of Personal Triumph From the Frontiers of Brain Science. By Norman Doidge
An amputee has a bizarre itch in his missing hand: unscratchable, it torments him. A neuroscientist finds that the brain cells that once received input from the hand are now devoted to the man’s face; a good scratch on the cheek relieves the itch. Another amputee has 10 years of excruciating “phantom” pain in his missing elbow. When he puts his good arm into a box lined with mirrors he seems to recognize his missing arm, and he can finally stretch the cramped elbow out. Within a month his brain reorganizes its damaged circuits, and the illusion of the arm and its pain vanish.
Research into the malleability of the normal brain has been no less amazing. Subjects who learn to play a sequence of notes on the piano develop characteristic changes in the brain’s electric activity; when other subjects sit in front of a piano and just think about playing the same notes, the same changes occur. It is the virtual made real, a solid quantification of the power of thought. From this still relatively primitive experimental data, theories can be constructed for the entirety of human experience: creativity and love, addiction and obsession, anger and grief — all, presumably, are the products of distinct electrical associations that may be manipulated by the brain itself, and by the brains of others, for better or worse.
More here.