Figure 1.

FMA implantation and task design. A–C, Array locations for animals B, S, and Z, respectively. Two arrays were placed in F5 on the bank of the arcuate sulcus (AS). Two additional arrays were placed in AIP toward the lateral end of the intraparietal sulcus (IPS). In animals B and Z, two more arrays were placed on the bank of the central sulcus (CS). The cross shows medial (M), lateral (L), anterior (A), and posterior (P) directions. Note that animal S was implanted in the left hemisphere and animals B and Z in the right hemisphere. D, Sketch of an animal in the experimental setup. The cues were presented on a monitor projected onto a mirror, making the light dots appear superimposed onto the grasping handle. E, Delayed grasping task with two grip types (Task 1). An example of each grip type can be seen during the movement epoch (top, power grip; bottom, precision grip). The handle was rotated to a supine orientation for demonstration purposes only. F, Delayed grasping task with two grip types and three decision conditions (Task 2). Free-choice trials were presented twice as often as each of the other conditions. Delayed-instructed trials contained a second grip cue turning a free-choice trial into a delayed-instructed trial. Trials were presented in a pseudorandom order.