Nervous systems control purposeful movement, both within and outside the body, which is essential for the survival of an animal. The movement control functions of globus pallidus (GP), subthalamic nucleus (STN) and zona incerta (ZI) were analyzed in monkeys reaching for seen targets. Temporal profiles of the hand movements of monkeys and the synchronized flow of electrochemical energy through these basal ganglia were analyzed in terms of a theory of goal-directed movement. Theoretical and empirical analysis indicated: (i) the neural information for controlling movement is the relative-rate-of-change of flow of electrochemical energy in neurons rather than the flow itself; (ii) GP is involved in creating prospective electrochemical flow to guide movement; (iii) STN is involved in registering the perceptual electrochemical flow monitoring the movement; (iv) ZI is involved in integrating the prospective and perceptual electrochemical flows to power the muscles and thence the movement. Possible implications for PD are discussed.