Figure 2.

Experimental setup and task. A, Subjects sat facing a mirror onto which a start position, targets, and a cursor representing the hand position were projected using a horizontally mounted HDTV and rested their arms in an air sled system placed on a glass tabletop. Subjects' movements were recorded using two FOB sensors, one placed on the upper arm and the other on the hand. B, The experimental task consisted of reaching movements to eight targets arranged in a circle in three sessions. In the “baseline” session, the hand and cursor feedback were matched. During the “adaptation” session, the cursor was rotated 30° (deg) counterclockwise relative to the direction of hand motion, while during the “after-effect” session the hand and cursor were matched again.