Figure 1.

A, Time course of experiment. After display of start message for 2 s, target (circle) and cursor (cross) were presented on the screen. Subjects continuously tracked a moving target with cursor using joystick for 21 s, with rotational perturbations of +90° or −90°. Task blocks were interleaved with rest periods of 4 s. B, Examples of target trajectory under different rotation types and velocity types in single block. C, Examples of horizontal positions of target with those of cursor within single block of first (left) and last (right) practice sessions.