Fig. 6.

Coordinated, sequential grasp-and-release movements produced by multielectrode, multi-USEA stimulation. USEA stimulation generated grip sufficient to hold a ball. Bottom: electrodes used in the grip sequence for the 3 implanted nerves; filled dots indicate electrodes active at the time of the picture. A: rest position. B: wrist extension. C: 1-s hand opening and forearm supination to accept the ball. The experimenter introduces the ball to the anesthetized primate's hand. D: 1-s power grip. E: wrist and fingers extend again, releasing the ball. F: wrist flexes and forearm pronates to drop the ball.