Figure 5.

Changes in the path and direction of finger movement, in response to changes in target speed during interception sessions. Parts A and B show examples from two different paths for one subject (Subject 8). The left column depicts the 100 ms perturbation condition and the right column depicts the 400 ms perturbation condition. In the top panel of each part of the figure the target trajectory is shown for this condition (black thin lines). The target followed the trajectory along the direction shown by the arrows. The GO signal is represented by the solid black circle and the perturbation location (if there was one) is shown with the open circle. The finger average movement paths for this one subject in the one trajectory are shown emanating from the bottom of this aspect of the figure. Average finger movement paths are shown for all three perturbation magnitude conditions. In the bottom panel in each part of the figure the finger direction over time for each perturbation magnitude condition is shown over the time of the trial for the current target trajectory. Time zero is the time of the GO signal (not shown). The finger movement directions are color-coded and have varying line style; for the slower perturbation (−0.5, blue dotted lines for finger direction, blue line with the most hatching for finger position), the faster perturbation (+1.5, red solid line for finger direction and red line with the least hatching for finger position) and the control situation (0, green dashed line for finger direction and green line with intermediate hatching for finger position). Each trace is an average (±1SEM) of all successful first movement attempts in each condition. Vertical lines in each panel represent the time of finger movement onset (black) and the time finger direction separates (gray) across all subjects and all trials in the particular target trajectory and perturbation time condition.