Abstract
Six results are reported. (a) Reaching accuracy increases when visual
capture of the target is allowed
(e.g., target on vs. target off at saccade onset). (b) Whatever the
visual condition, trajectories diverge only
after peak acceleration, suggesting that accuracy is improved through
feedback mechanisms. (c) Feedback
corrections are smoothly implemented, causing the corrected and uncorrected
velocity profiles to
exhibit similar shapes. (d) Initial kinematics poorly predict final
accuracy whatever the condition,
indicating that target capture is not the only critical input for
feedback control. (e) Hand and eye final
variability are unrelated, suggesting that gaze direction is not a
target signal for arm control. (f) Extent
errors are corrected without modification of movement straightness;
direction errors cause path curvature
to increase. Together these data show that movements with straight
paths and bell-shaped velocity
profiles are not necessarily ballistic.
Users
Please
log in to take part in the discussion (add own reviews or comments).