Spatially Similar Practice Immediately Following Motor Sequence Learning Eliminates Offline Gains

Robust offline performance gains, beyond those that would be anticipated by being exposed to additional physical practice, have been reported during procedural learning. However, practice of unrelated procedural task performance within 4-6 hour after initial practice has been revealed to eliminate offline improvement. The present experiment assessed the relative impact of experiencing supplemental practice of a spatially or a motorically-similar procedural task immediately following practice of a target motor sequence task. Based on a contemporary model of procedural skill acquisition forwarded by Hikosaka and colleagues, we assumed exposure to a spatial compatible motor sequence rather than interfering would support rapid improvement in the production of the spatial variant of the target task without compromising important memory processes, which are conducted offline to improve delayed performance of the target task.

Findings revealed the often demonstrated offline gain when the target task was performed in the absence of interfering task practice as well as the elimination of such gains when target task practice was followed with additional practice of either a novel or motorically-similar motor sequence task. While immediate performance of the spatially-similar task was facilitated by preceding target task training, offline gains for the target task no longer emerged. These data are consistent with a central premise of Hikosaka et al.?s model that a spatial reference system plays an important role early during motor sequence learning but highlight the sensitivity of offline gains to task practice order.