Abstract
Recent research has cast doubts on the idea that movement variability should solely be seen as noise of the system added to the motor command. A study of Wu et al. (2014) suggests that high levels of motor variability might help adaptation to new environments. This idea is appealing, as it could explain individual differences in adaptation between subjects. Here we determine if the level of variability could also explain differences in adaptation to temporal delays in interception. More specifically, we are interested to see if there is a difference between the task-relevant and task-irrelevant dimension. Subjects performed reaching movements on a graphic tablet towards a target that was moving either from left to right, or from right to left with various speeds. Their hand was occluded from vision and their movement was represented by a red cursor. Subjects were instructed to intercept the target with their cursor. After a baseline of 80 trials, we introduced a temporal delay of the cursor of 50 ms during 40 trials. We measured baseline temporal variability in the x- and y-dimension during the movement, and total adaptation after the temporal perturbation. We found a significant positive correlation (r=0.56) between the baseline variability in the y-dimension and the total adaptation to the temporal perturbation. This relationship was not present for the variability in the x-dimension. The results suggest a positive role for task-relevant variability in total adaptation. A possible explanation could be an increased sensitivity to previously made errors as suggested by Herzfeld et al. (2014).
Meeting abstract presented at VSS 2017