Figure 1.

Brain-controlled Functional Electrical Stimulation (FES). The monkey’s forearm and digit flexor muscles were temporarily paralyzed by a peripheral nerve block. Recordings from the motor cortex were used to infer the monkey’s attempted patterns of muscle activity and thereby control electrical stimulation that restored the monkey’s ability to perform a functional grasping task. The ball grasp device was equipped with a contact sensor and a task-completion sensor that were activated when the monkey initially touched the ball and dropped it into the tube, respectively.