How is responsibility assigned in a redundant system during a bimanual task ?

Details

Supervisors

Lefèvre, Philippe ; Thonnard, Jean-Louis

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil biomédical

Abstract

Redundancy is a key feature of the motor system of human beings. Indeed, the numerous combinations of motor commands for the different effectors lead to various ways of achieving a desired task. When doing a bimanual task, the motor system will always distribute the work across the different effectors according to what it estimates to be the optimal way to produce the desired movement. But, when it faces an error, the motor system usually does not know which effector caused it. The aim of our study is to investigate the way our motor system assigns responsibility when it faces an error induced by a hidden visuomotor rotation during a bimanual task. To do so, we induced progressively the visuomotor rotation until reaching an amplitude of 30 degree and then, we anchored the visuomotor rotation at this amplitude. Our results show that the responsibility is assigned across the effectors according to biomechanical constraints. The force production is always driven by the preferential direction of the hand, meaning that the hand produces more force when the target to reach is close to its preferential direction. Moreover, corrections in the trajectory are mostly achieved by the other hand, so the one for who the target is not located close to its preferential direction of force production. Eventually, our results also show that handedness does not impact the force production or the correction of the visuomotor rotation.