Résumé
The relationship between implicit (i.e., unconscious) and explicit (i.e., conscious strategy) contributions to visuomotor adaptation is currently debated, with evidence supporting both their dependence and independence. We have previously suggested that mental fatigue interferes with the engagement of explicit processes during motor learning, while implicit processes are unaffected, thus supporting an independent relationship between the two. Extending from this work, the current research looked to establish the impact of mental fatigue on visuomotor adaptation, when explicit contributions were absent. Participants trained to reach with misaligned cursor feedback that was rotated 20° clockwise relative to hand motion in a virtual environment. These rotated training trials were completed following a mentally fatiguing time load dual back task (Mental Fatigue (MF) group) or watching a documentary (Control (CTL) group). The extent of visuomotor adaptation was similar for both groups across all rotated reach training trials and this adaptation was confirmed to have arisen implicitly. Furthermore, no significant difference in implicit adaptation was observed between groups, and the correlation between mental fatigue and implicit adaptation was weak. These results suggest that mental fatigue does not interfere with visuomotor adaptation when it is driven implicitly and supports our proposal that mental fatigue exclusively interferes with the engagement of explicit strategies. Overall, these findings suggest that implicit and explicit processes independently contribute to visuomotor adaptation.
Key words: Conscious strategy, visuomotor adaptation, mental fatigue, motor learning, implicit.
