Interleaved rather than repetitive practice (RP) is associated with superior retention of motor skills. It has been argued that this results from improved post-practice consolidation reflected in greater offline gains following interleaved practice (IP). The magnitude of this offline benefit has been associated with greater recruitment of supplementary motor area (SMA) during encoding. The present study administered anodal or cathodal transcranial direct current stimulation (tDCS) during interleaved or RP respectively in an attempt to modify the activity at SMA and the concomitant retention outcomes commonly associated with these training formats. Sixty-nine participants were assigned to one of four experimental conditions that included: IP-sham, RP-sham, IP-cathodal tDCS, and RP-anodal tDCS. Real or sham stimulation at SMA was administered during practice of three unique 6-key discrete sequence production tasks which lasted approximately 20-min. Tests were administered prior to practice and immediately after practice as well at 6-h, 24-h, and 72-h after practice ended. As anticipated, IP resulted in poorer acquisition but superior offline gain. Enhanced offline gain following interleaved training resulted from rapid stabilization of performance within the first 6-h following encoding and overnight improvement that continued over multiple sleep episodes. Administration of anodal stimulation at SMA during RP improved performance during training compared to sham but this benefit was short lived as forgetting during the first 6-h after practice was consistent with that observed for the sham counterpart. However, supplementing RP with anodal stimulation at SMA did foster overnight offline performance gains not displayed by individuals that experienced RP in the absence of stimulation.

中文翻译：

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经颅直流电刺激辅助运动区域会影响交错和重复性练习计划对保留运动技能的有效性。

交错练习而非重复练习（RP）与出色的运动技能保留能力相关。有人认为，这是由于练习后合并的改进而产生的，这反映在交错练习（IP）之后，离线收益增加了。这种离线收益的程度与编码过程中补充补充运动区域（SMA）有关。本研究分别在交错或RP期间进行了阳极或阴极经颅直流电刺激（tDCS），以试图改变SMA的活性以及通常与这些训练方式相关的保留结果。69名参与者被分配到以下四个实验条件之一，这些条件包括：IP伪，RP伪，IP阴极tDCS和RP阳极tDCS。在执行三个独特的6键离散序列产生任务的过程中，对SMA进行了真实刺激或假刺激，持续了大约20分钟。在练习前和练习后以及练习结束后的6小时，24小时和72小时立即进行测试。正如预期的那样，IP导致获取效果较差，但脱机收益却更高。交错训练后增强的离线增益是由于编码后的前6小时内性能快速稳定，以及过夜睡眠后持续改善的过夜效果。与假手术相比，在RP期间在SMA上给予阳极刺激可改善训练过程中的表现，但这种益处是短暂的，因为在练习后的前6小时内忘记了与假手术对应者相吻合。然而，