Wilkins Erik W, Young Richard J, Houston Daniel, Kawana Eric, Lopez Mora Edgar, Sunkara Meghana S, Riley Zachary A, Poston Brach
Department of Kinesiology and Nutrition Sciences, University of Nevada, Las Vegas, NV 89154, USA.
Interdisciplinary Ph.D. Program in Neuroscience, University of Nevada, Las Vegas, NV 89154, USA.
Brain Sci. 2024 Jul 12;14(7):694. doi: 10.3390/brainsci14070694.
Transcranial direct current stimulation (tDCS) increases primary motor cortex (M1) excitability and improves motor performance when applied unilaterally to the dominant hemisphere. However, the influence of tDCS on contralateral M1 excitability both during and after application has not been quantified. The purpose was to determine the influence of tDCS applied to the dominant M1 on the excitability of the contralateral non-dominant M1. This study employed a double-blind, randomized, SHAM-controlled, within-subject crossover experimental design. Eighteen young adults performed two experimental sessions (tDCS, SHAM) in counterbalanced order separated by a one-week washout. Transcranial magnetic stimulation (TMS) was used to quantify the excitability of the contralateral M1 to which anodal tDCS was applied for 20 min with a current strength of 1 mA. Motor evoked potential (MEP) amplitudes were assessed in 5 TMS test blocks (Pre, D5, D10, D15, and Post). The Pre and Post TMS test blocks were performed immediately before and after tDCS application, whereas the TMS test blocks performed during tDCS were completed at the 5, 10, and 15 min stimulation timepoints. MEPs were analyzed with a 2 (tDCS, SHAM) × 5 (Pre, D5, D10, D15, Post) within-subject ANOVA. The main effect for ( = 0.213), the main effect for ( = 0.502), and the × interaction ( = 0.860) were all not statistically significant. These results indicate that tDCS does not modulate contralateral M1 excitability during or immediately after application, at least under the current set of common tDCS parameters of stimulation.
经颅直流电刺激（tDCS）单侧应用于优势半球时，可增加初级运动皮层（M1）的兴奋性并改善运动表现。然而，tDCS在应用期间及应用后对 contralateral M1 兴奋性的影响尚未量化。本研究的目的是确定应用于优势 M1 的 tDCS 对 contralateral 非优势 M1 兴奋性的影响。本研究采用双盲、随机、假刺激对照、受试者内交叉实验设计。18 名年轻成年人以平衡顺序进行了两个实验阶段（tDCS、假刺激），中间间隔一周的洗脱期。经颅磁刺激（TMS）用于量化 contralateral M1 的兴奋性，对其施加阳极 tDCS，电流强度为 1 mA，持续 20 分钟。在 5 个 TMS 测试块（预测试、刺激 5 分钟后、刺激 10 分钟后、刺激 15 分钟后和刺激后）中评估运动诱发电位（MEP）幅度。预测试和刺激后 TMS 测试块分别在 tDCS 应用前和应用后立即进行，而在 tDCS 期间进行的 TMS 测试块在刺激 5、10 和 15 分钟时间点完成。采用受试者内 2（tDCS、假刺激）×5（预测试、刺激 5 分钟后、刺激 10 分钟后、刺激 15 分钟后、刺激后）方差分析对 MEP 进行分析。时间因素的主效应（F = 0.213）、组间因素的主效应（F = 0.502）以及组间×时间交互作用（F = 0.860）均无统计学意义。这些结果表明，至少在当前这组常见的 tDCS 刺激参数下，tDCS 在应用期间或应用后即刻不会调节 contralateral M1 的兴奋性。
