Fig. 3.

Changes in endpoint location over the course of practice. Black lines represent data for reaches toward the 45-degree target, and gray lines represent reaches toward the 135-degree target, regardless of the training target. A: the vertical coordinate immediately increases and then rapidly drops when the force field is applied during the exposure block. The pattern is similar for the 2 targets. B: the horizontal coordinate diverges for the 2 targets during the exposure block, and this separation is maintained over the test blocks. Negative numbers indicate endpoints to the left of center. C: for the left hand, the vertical coordinate shows the same immediate increase and rapid drop when the force perturbation is introduced. D: the horizontal coordinate for the left hand diverges across the test blocks.