Parkinson's, depression and the switch that might turn them off
Deep brain stimulation is becoming very precise. This technique allows surgeons to place electrodes in almost any area of the brain, and turn them up or down -- like a radio dial or thermostat -- to correct dysfunction. Andres Lozano offers a dramatic look at emerging techniques, in which a woman with Parkinson's instantly stops shaking and brain areas eroded by Alzheimer's are brought back to life.