Fig. 1.

Movement data. a RMS error of the OH over training sequence for 500 ms delay condition, averaged across all subjects. An exponential fit to the data is shown to demonstrate learning. By the final 35 trials adaptation was complete, as the slope of the RMS error across these trials was not significantly different from zero. b Mean velocities across subjects for the test trials at the medium speed for each of the delay conditions (blackcurves: 0 ms; bluecurves: 250 ms; redcurves: 500 ms). Velocity curves for the MH (dashed lines) are bell-shaped and time-shifted for each delay condition to illustrate the timing of the forces incident on the OH. Predictive responses can be seen for the 250 and 500 ms delay conditions for the OH (solidlines) as positive-going peaks before the onset of the MH velocity and these are followed by a deflection and then an overshoot. c Mean position data for the OH (solid lines) and MH (dashed lines) across subjects for the test trials at the medium speed for each of the delay conditions. Position curves for the MH are time-delayed. The OH is always pushed back (negative) by the force before returning to the original zero position. Anticipatory peaks are difficult to make out in this case but examples can be seen in Fig. 2a