Neuroscientists believe that the loss of the dopamine-rich nerves in the substantia nigra results is an over-activity of a ‘brake’ mechanism in the basal ganglia which in turn inappropriately shuts down movement. Deep brain stimulation (DBS) takes advantage of our knowledge of this brain wiring by applying a small electric current into a target area called the subthalamic nucleus located deep within the basal ganglia to switch off the brake and free-up movement. It is an expensive and risky procedure but it can provide a new lease of life particularly to those patients for whom conventional drug treatment no longer seem to work.