The Basal Ganglia comprise a group of forebrain nuclei that are interconnected with the cerebral cortex, thalamus and brainstem. Basal ganglia circuits are involved in various functions, including motor control and learning, sensorimotor integration, reward and cognition. The importance of these nuclei for normal brain function and behavior is emphasized by the numerous and diverse disorders associated with basal ganglia dysfunction, including Parkinson's disease, Tourette's syndrome, Huntington's disease, obsessive-compulsive disorder, dystonia, and psychostimulant addiction. . . The Handbo.