Division of Stroke and Vascular Neurology, Department of Neurology, Duke University Medical Center, Durham, NC, USA.
Non-Invasive Brain Stimulation Laboratory, Department of Health and Kinesiology, Texas A&M University, College Station, TX, USA.
Neurobiol Learn Mem. 2021 Feb;178:107365. doi: 10.1016/j.nlm.2020.107365. Epub 2020 Dec 19.
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。与重复练习相比，在交错练习中报告M1的募集更为广泛，这种差异募集被认为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给予阳极直流电刺激（tDCS），试图通过增加 M1 活动来提高重复练习中的 M1 活动，目的是提高接触这种训练模式的个体的保留表现。54 名参与者被分配到三个实验组中的一个，包括：交错-假刺激组、重复-假刺激组和重复-阳极 tDCS 组。在大约 20 分钟的时间内，对 M1 进行真实或假刺激。在练习之前、练习后立即以及练习完成后 6 小时和 24 小时评估无任何刺激时的表现。正如预期的那样，对于假刺激条件，交错练习与重复练习相比，离线增益更好。这表现为 6 小时后表现更快稳定，以及在夜间睡眠期间表现增强。与重复练习假刺激组相比，在重复练习期间给予 M1 阳极刺激可提高 6 小时和 24 小时测试的离线增益。这些数据与以下观点一致，即与交错练习相比，重复练习时 M1 的激活减少会阻碍离线增益，并且 M1 在新运动技能的早期巩固中发挥重要作用，即使在同时习得多个新技能的情况下也是如此。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。
