Effects of tool use and perturbation during motor adaptation on hand localization


Our brain has a remarkable capacity for learning movements and adapting them to accomplish a motor goal. In many adaptation studies, participants move in a 2D plane while their hand is represented by a cursor. When visual feedback of hand position is misaligned, people can quickly compensate for this perturbation, show persistent reach aftereffects, and even misestimate the location of the unseen hand in the direction of previous visual training. However, it is unknown how well this generalizes to real-world settings or to the tools we use every day. Here we will use immersive virtual reality to test if end-effector shifts are also observed in more naturalistic virtual reality environments and if they extend to tools as end effectors. In Study 1, we replicated our previous work where we found shifts in end-effector localization after adapting reach movements to a 30° visuomotor rotation of the hand, showing a similar magnitude of both shifts in unseen hand location and reach aftereffects following training to the perturbation in the VR environment. In the next condition (Study 2), we extend this paradigm to investigate how well people can adapt when aiming with a common tool, like a pen, and whether the tool location is also recalibrated. We will measure the extent that the unseen location of hand-held tool, as well as the hand (in separate trials) recalibrates with adaptation. Our results will provide insight into the adaptative processes involved when learning to wield tools in more complicated, realistic environments.