Influence of motor imagery on learning under complex external dynamics.

Humans are remarkable in their ability to adapt to changes in the dynamics of a movement. The mechanisms by which the brain controls body movements are important in the fields of robotics and neurosciences. Robots are largely used to study the adaptive properties of human motor system. If rehabilitation robots are used in conjunction with techniques for functional brain imaging, in principle the motor learning can be facilitated for rehabilitation purposes. In this study, we use motor imagery technique to improve the learning rate in a robot-based adaptation task. We tried to determine whether humans can learn an internal model of a complex mixed force field (V+P) that was the sum of a velocity-dependent force field (V) and a position-dependent force field (P). The results suggest that the motor learning can be influenced by mental practice and could be used to increase the rate of adaptation.