Abstract
Movement planning consists of several processes related to the preparation of a movement such as decision making, target selection, application of task demands, action selection and specification of movement kinematics. These numerous processes are reflected in the reaction time, which is the time that it takes to start executing the movement. However, not all the processes that lead to motor planning increase reaction time. In this paper, we wanted to test whether tuning the control policy to task demands contributes to reaction time. Taking into account that the tuning of the control policy differ for narrow and wide targets, we used a timed response paradigm in order to track the amount of time needed to tune the control policy appropriately to task demands. We discovered that it does not take any time during motor planning and even that it can occur indistinguishably during motor planning or during motor execution. That is, the tuning the control policy was equally good when the narrow or large target was displayed before than when it was displayed after. These results suggest that the frontier between motor planning and execution is not as clear cut as it is often depicted.
New & Noteworthy Movement preparation consists of different processes such as target selection, and movement parameters selection. We investigate the time that it take to tune movement parameters to task demands. We found that the brain does this instantaneously and that this can even happen during movement. Therefore, this suggests that there exist an overlap during movement planning and execution.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Major change is the addition of a new figure (Fig.3) Textual clarifications have been performed as well.