Engagement of primary motor cortex (M1) is important for successful consolidation of motor skills. Recruitment of M1 has been reported to be more extensive during interleaved compared to repetitive practice and this differential recruitment has been proposed to contribute to the long-term retention benefit associated with interleaved practice. The present study administered anodal direct current stimulation (tDCS) during repetitive practice in an attempt to increase M1 activity throughout repetitive practice with the goal to improve the retention performance of individuals exposed to this training format. Fifty-four participants were assigned to one of three experimental groups that included: interleaved-sham, repetitive-sham, and repetitive-anodal tDCS. Real or sham stimulation at M1 was administered during practice of three motor sequences for approximately 20-min. Performance in the absence of any stimulation was evaluated prior to practice, immediately after practice as well as at 6-hr, and 24-h after practice was complete. As expected, for the sham conditions, interleaved as opposed repetitive practice resulted in superior offline gain. This was manifest as more rapid stabilization of performance after 6-h as well as an enhancement in performance with a period of overnight sleep. Administration of anodal stimulation at M1 during repetitive practice improved offline gains assessed at both 6-h and 24-h tests compared to the repetitive practice sham group. These data are consistent with the claims that reduced activation at M1 during repetitive practice impedes offline gain relative to interleaved practice and that M1 plays an important role in early consolidation of novel motor skills even in the context of the simultaneous acquisition of multiple new skills. Moreover, these findings highlight a possible role for M1 during sleep-related consolidation, possibly as part of a network including the dorsal premotor region, which supports delayed performance enhancement.

初级运动皮层 (M1) 的参与对于成功巩固运动技能很重要。据报道，与重复练习相比，在交错过程中 M1 的招募范围更广，并且这种差异招募已被提议有助于与交错练习相关的长期保留益处。本研究在重复练习期间实施阳极直流电刺激 (tDCS)，试图在整个重复练习中增加 M1 活动，目的是提高暴露于这种训练形式的个人的保留性能。五十四名参与者被分配到三个实验组之一，其中包括：交错假、重复假和重复阳极 tDCS。在大约 20 分钟的三个运动序列练习期间，在 M1 处进行真实或假刺激。在练习前、练习后立即以及练习完成后 6 小时和 24 小时评估在没有任何刺激的情况下的表现。正如预期的那样，对于虚假条件，交错而不是重复练习导致了卓越的离线收益。这表现在 6 小时后性能更迅速稳定，并且在夜间睡眠一段时间后性能提高。与重复练习假手术组相比，在重复练习期间在 M1 处进行阳极刺激改善了在 6 小时和 24 小时测试中评估的离线收益。这些数据与以下说法一致，即在重复练习期间减少 M1 的激活会阻碍相对于交错练习的离线增益，并且即使在同时获得多项新技能的情况下，M1 在新运动技能的早期巩固中也起着重要作用。此外，这些发现强调了 M1 在睡眠相关巩固过程中的可能作用，可能作为包括背侧运动前区在内的网络的一部分，支持延迟的性能增强。