Figure 1.

Task paradigm and FMA implantation details. Animals were trained to perform two tasks. A, Delayed grasping task, consisting of four epochs: baseline, cue, planning, and movement. The task was performed in the dark, except for the cue period when the handle was visible together with an instruction for grasp type (green dot, power grip; white dot, precision grip; red dot, fixation light). B, Brain control task. This task proceeded as in A, except at the end of the planning epoch, where the planned grasp was decoded and visually fed back to the monkey (photograph of grasp) without requiring the animal to actually execute the movement. C, Placement of FMAs in Animal S. Two arrays were placed in F5 on the bank of the arcuate sulcus (AS). Two further arrays were placed in AIP toward the lateral end of the intraparietal sulcus (IPS). CS, Central sulcus. The cross shows medial (M), lateral (L), anterior (A), and posterior (P) directions. D, Schematic of FMA placement in Animal S including FMA numbering. The dark edge on each FMA indicates the row of electrodes with the greatest lengths (see Fig. 2). Annotations are the same as in C. E, Schematic of FMA placement in Animal Z.