Fig. 1.

Experimental setup. A: during baseline movements, cursor feedback accurately reflects the position of the subject's hand [veridical, 0° rotation (ROT); see materials and methods for group definitions]. With onset of the 30° rotation, cursor feedback is rotated about the origin (the start position) by 30°. Dashed line: hand path, solid line: cursor path, green circle movement start position, blue circle with gray ring: target. B: perturbation schedule for principal groups and the control group (n = 10 per group). Double gray vertical lines indicate a break across days. C: subject-averaged learning curves from the initial rotation session for the four principal groups. Shaded regions indicate ± SE. Reach direction is abbreviated as “Reach dir.” D: mean attained reach direction for each group at the end of their initial exposure to the rotation. Values represent the mean reach direction across subjects on the last trial of adaptation within each group. Error bars indicate SE.