Motor adaptation scaled by the difficulty of a secondary cognitive task.
BACKGROUND
Motor learning requires evaluating performance in previous movements and modifying future movements. The executive system, generally involved in planning and decision-making, could monitor and modify behavior in response to changes in task difficulty or performance. Here we aim to identify the quantitative cognitive contribution to responsive and adaptive control to identify possible overlap between cognitive and motor processes.


RESULTS
We developed a dual-task experiment that varied the trial-by-trial difficulty of a secondary cognitive task while participants performed a motor adaptation task. Subjects performed a difficulty-graded semantic categorization task while making reaching movements that were occasionally subjected to force perturbations. We find that motor adaptation was specifically impaired on the most difficult to categorize trials.


CONCLUSIONS
We suggest that the degree of decision-level difficulty of a particular categorization differentially burdens the executive system and subsequently results in a proportional degradation of adaptation. Our results suggest a specific quantitative contribution of executive control in motor adaptation.
Taylor
Jordan A
JA
Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, Missouri, United States of America.
Thoroughman
Kurt A
KA
D000222:Adaptation, Physiological; D000328:Adult; D003071:Cognition; D003625:Data Collection; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D009043:Motor Activity; D011930:Reaction Time