Figure 1.

Experimental setup. (A) Diagram of experimental apparatus. (B) Experimental protocol. Subjects performed up to 400 trials in a single block, divided into four epochs: Baseline (veridical feedback), Initial Learning (30° counterclockwise rotation), Unlearning, and Re-learning (30° counterclockwise rotation). During the Unlearning epoch, subjects experienced one of four manipulations: task error clamped to zero (Clamp), removal of visual feedback (No Feedback), veridical feedback of hand position (Washout), or inactivity for 740 s (Time).