Adaptation to Virtual Surgeries Across Multiple Practice Sessions

Myoelectric control of an isometric reaching task in a virtual environment allows to investigate motor adaptation after simulating a perturbation of the muscle pulling directions (virtual surgeries). Such perturbations can be compatible or incompatible with the muscle synergies involved in the generation of multidirectional forces. A recombination of the synergies can generate forces in all directions after a compatible surgery but require new synergies after an incompatible surgery. Previous work demonstrated that, in a single experimental session, subjects adapted only to a compatible perturbation. In this study, we investigated whether extended practice leads to adaptation also after an incompatible perturbation. After three daily sessions, participants who practiced the incompatible surgery improved their performance, achieving a similar performance to that of those who practiced the compatible surgery. These results suggest that extended practice with incompatible virtual surgeries allows learning how to skillfully use novel muscle patterns.