Abstract
In the present study, we investigated the mechanism of the central nervous system to adapt the finger movement to the stable force field overlapped on the unstable force field. In the experiments, we analyzed after-effects on adaptation of a point-to-point index finger movement to a static force field (SF), divergent force field (DF) and composite force field (CF), in which the SF overlapped on the DF. Experimental results indicated that the adaptation to the SF was achieved by the generation of counteracting forces through the feed-forward motor command, whereas the modification of the limb impedance was utilized for the unpredictable interaction in the DF. Moreover, it was suggested that the adaptation to the CF was operated by the generation of counteracting forces in the feed-forward manner rather than the modification of the limb impedance.
