Comparing Online Adjustments to Distance and Direction in Fast Pointing Movements

It has been suggested that movements are planned in terms of direction and distance. If so, online adjustments to changes in the direction and distance of the movements may also differ. The authors therefore investigated whether fast online movement adjustments are the same for perturbations of the direction and of the distance. While subjects made fast pointing movements, the authors perturbed either target direction or distance or both shortly after movement initiation. Both kinds of perturbations resulted in accurate online adjustments. The latency and intensity of corrections for distance and direction perturbations were quite similar. This suggests that there might be one mechanism controlling both distance and direction perturbations. Copyright © 2013 Taylor & Francis Group.