Interactive effects of visuomotor perturbation and an afternoon nap on performance and the flow experience

Effects of the amount of practice and time interval between practice sessions on the retention of internal models

The amount of practice and time interval between practice sessions are important factors that influence motor learning efficiency. Here, we aimed to reveal the relationship between the retention and consolidation of a new internal model, and the amount of practice and time interval between practice sessions. We employed a visuomotor rotation tracking task to test the hypotheses that (1) a new internal model consolidates owing to extensive practice after reaching a task performance plateau and (2) a longer time interval between practice sessions makes it difficult to activate a new internal model. The participants were assigned to one of the four groups that differed in terms of the amount of practice and the time interval between practice sessions. They performed a tracking task in which they experienced 120° clockwise visuomotor rotation and were required to track a moving target on a computer display using a mouse cursor. To evaluate the retention and consolidation of a new internal model, we calculated the aftereffects and savings as measures of motor learning. To the best our knowledge, this is the first study to manipulate both the amount of practice and the time interval between practice sessions simultaneously in one experiment using a visuomotor tracking task. Our results support the previously reported idea that extensive practice is necessary for the consolidation of a new internal model.

Influence of Speed and Accuracy Constraints on Motor Learning for a Trajectory-Based Movement

This study investigated the influences of task constraint on motor learning for a trajectory-based movement considering the speed-accuracy relationship. In the experiment, participants practiced trajectory-based movements for five consecutive days. The participants were engaged in training with time-minimization or time-matching constraints. The results demonstrated that the speed-accuracy tradeoff was not apparent or was weak in the training situation. When the participants practiced the movement with a time-minimization constraint, movement errors did not vary, whereas the movement time decreased. With the time-matching constraint, the errors decreased as a session proceeded. These results were discussed in terms of the combination of signal-dependent noises and exploratory search noises. It is suggested that updating spatial and temporal factors does not appear to occur simultaneously in motor learning.