Abstract
Forming an internal model for adapted reaching movements to altered visual feedback requires a certain amount of practice. Numerous studies have shown the brain can quickly adapt to visual and force perturbations while performing reaching movements to both trained target and novel targets. But many of these studies have participants reach to only a small number of target locations repeatedly. Is learning comparable in the case where target locations are constantly different and participants only have a chance to reach once to each of them? We addressed this question by having subjects adapt their reaches to altered visual feedback of the hand either when repeatedly reaching to four targets (Repeated practice) or reaching only once to numerous target directions (Single practice). We also examined the extent to which this adaptation could transfer to untrained target locations. We found there is very little difference in learning rate between the two practice conditions. That is, participants were just as fast at learning a new visuomotor mapping when reaching once to each new target as they were when reaching over and over to the same targets. Likewise, we found that participants generalized to untrained targets similarly across exposure conditions. This suggests that the brain is as capable of deducing the required visuomotor adjustments following variable practice with unique targets as it is with repeated practice with the same targets.