Adaptive motor behaviors through dynamic interactions among the body, brain and environment

In daily life, humans must compensate for the resultant force arising from interaction with the physical environment. It has been shown that humans can acquire a neural representation of the relation between motor command and movement, i.e. learn an internal model of the environment dynamics. For example, Shadmehr et al have analyzed various reaching movements under velocity-dependent force field (VF) where the hand receives the external load in proportion to the hand velocity. It is then shown that human compensates for the external load by the feedforward control based on the internal model. It is here called. On the other hand, in manipulation tasks, such as opening a door, grasping a cup etc., the dynamic interaction between the human arm and external environment determines the stability of motion. Therefore, it has much important to adjust the arm impedance corresponding to the environment dynamics, which is called . The talk will discuss adaptive motor behaviors to dynamic environments in human voluntary movements. The experimental results demonstrate that human adaptation to a varying dynamic environment during reaching movements is achieved by programming the internal model control and impedance control in a feedforward manner. In addition, the talk will refer to application of motor learning to physical rehabilitation.