Adaptive control of movement deceleration during saccades
Fig 1
Acceleration and deceleration period commands exhibit some of the properties of the fast and slow system.
A. Experiment 1 trial structure. Following a vertical primary saccade, subjects experienced a rightward horizontal endpoint error. B. To quantify adaptation, we measured the horizontal displacement of the adapted saccade with respect to baseline saccades. We integrated horizontal eye velocity over the acceleration and deceleration periods to determine the displacement during each period. C. Training blocks. Each block consisted of four periods: initial adaptation, set break (brown line), re-adaptation, error clamp. D. Horizontal displacement during the acceleration period was smaller than during the deceleration period, but exhibited little or no forgetting at set breaks. E. Trial-to-trial rate of change in the horizontal displacement produced by the acceleration and deceleration period commands during the perturbation blocks. Rate of change was faster in the deceleration period. F. Effect of set break on the horizontal displacement in the perturbation blocks and error clamp blocks. At left we show adaptation aligned to set breaks and averaged across all periods. Bin size is 4 trials. Decay was much greater in deceleration period commands. At right, we calculated the percent loss during set breaks in the perturbation and error clamp periods (depicted at left). G. Decay in the acceleration and deceleration period commands during the error clamp period. Error bars are between subject SEM. Bin size is 4 trials.