A woman sits at her piano, practicing a five-finger exercise. For two hours a day, she practices the exercise over and over, her finger movements growing sharper, more precise and fluid. Another woman sits in a chair, hands still, and imagines playing the same five-finger exercise. For two hours a day, she practices in her mind and she can visualize herself getting faster, more melodic, more purposeful. After five days, the motor cortex corresponding to these finger movements has flourished in the brain of the woman playing the piano, proving that behaviors physically alter the brain. But what is more fascinating is that these neural changes also occurred in the woman who was simply imagining playing the piano. In other words, we can change the structure of our brains simply by thinking.

The human brain has historically been a mysterious thing, a slippery and elusive being. For years it was thought that the brain completed its development early and then sat fixed, immutable, and vulnerable to damage from which it could not heal. Then an opera singer with MS regains his soaring voice. A blind man teaches himself to see. A man with Parkinson’s cures his symptoms by walking. And research begins to teach us that the brain is not static, but a flexible organ with the ability to form itself to behavior, reorganize itself to accommodate change, and compensate for damage. The brain is inventive, responsive, and, through careful modulation, full of promise.