经颅直流电刺激和高精度经颅直流电刺激对健康成年人运动皮层兴奋性的影响

关键词：经颅直流电刺激  高精度经颅直流电刺激  经颅磁刺激  运动诱发电位  运动阈值  中枢传导时间

Keywords:transcranial direct current stimulation  high-definition transcranial direct current stimulation  transcranial magnetic stimulation  motor evoked potential  resting movement threshold  central motor conduction time

摘要：

      摘要 目的：经颅直流电刺激（tDCS）作为一种无创、安全的神经调控技术，已广泛应用于脑卒中康复、提高运动功能。然而，两种刺激方式之间的效果差异尚不明确。本研究旨在比较tDCS与高精度tDCS（HD-tDCS）对健康成年人运动皮层兴奋性的影响差异，为优化临床神经调控策略提供依据。 方法：符合纳入标准的40例健康受试者，随机分为A、B两组，每组20例。采用两阶段两处理交叉设计，A组第一阶段进行HD-tDCS中心阳极刺激，刺激部位为经颅磁（TMS）测量基线时静息运动阈值（RMT）较高一侧的运动皮层，强度1.5mA，时间20min；经过24h洗脱期，第二阶段进行tDCS阳极刺激，刺激部位及参数同第一阶段；B组先进行tDCS阳极刺激，洗脱期后，再进行HD-tDCS刺激。比较两组受试者在不同时间点双侧大脑运动皮质运动诱发电位（MEP）的变化，包括双侧RMT、RMT差值（ΔRMT）、皮质脊髓传导时间（CMCT）的变化。 结果：①不同阶段间，各观察值差异无显著性意义（P>0.05）。②与基线相比，两种方式阳极刺激后即刻，双侧RMT、ΔRMT显著降低、刺激侧CMCT缩短（P<0.05）。③刺激侧RMT：tDCS刺激后即刻降低较明显，而HD-tDCS降低峰值出现在30min，均于120min后逐渐趋于基线水平；30min以后两种方式间差值变化显著（P<0.05）。④非刺激侧RMT：tDCS刺激后即刻升高明显，后续两者变化趋势一致，差异无显著性意义。⑤两种方式刺激后双侧CMCT均降低，后续变化无显著性差异。 结论：tDCS对于RMT即刻调节作用显著，而HD-tDCS的后续效应更显著。

Abstract:

      Abstract Objective： Transcranial direct current stimulation （tDCS）， a non-invasive and safe neuromodulation technique， has been widely applied in stroke rehabilitation and motor function enhancement. However，differences in the effects of conventional tDCS and high-definition tDCS (HD-tDCS) remain unclear. This study aims to compare the effects of tDCS and HD-tDCS on motor cortex excitability in healthy adults， providing evidence for the optimization of clinical neuromodulation strategies. Method： Forty healthy participants who met the inclusion criteria were enrolled and randomly assigned to two groups （group A and group B）， with 20 participants in each group. A two-phase， two-treatment crossover design was employed. In the first phase， participants in Group A received HD-tDCS with a center-anodal configuration over the motor cortex corresponding to the hemisphere with a higher resting motor threshold (RMT) determined by transcranial magnetic stimulation (TMS). The stimulation intensity was 1.5 mA and lasted for 20 minutes. After a 24-hour washout， the second phase involved anodal tDCS with identical stimulation parameters and location. In contrast， group B first received anodal tDCS followed by HD-tDCS after the washout period. Changes in motor evoked potential （MEP） of the bilateral motor cortices were assessed at multiple time points， including changes in bilateral RMT， the RMT difference （ΔRMT）， and central motor conduction time （CMCT）. Result： No significant differences were found between the two phases for any of the observed variables （P>0.05）. Compared with baseline， both stimulation methods led to immediate and significant reductions in bilateral RMT and ΔRMT， as well as shortened CMCT on the stimulated side （P<0.05）. On stimulated-side, tDCS produced a more immediate reduction in RMT， while HD-tDCS showed a peak reduction at 30 minutes post-stimulation. In both cases， RMT gradually returned to baseline by 120 minutes. A significant difference in RMT changes between the two methods was observed after 30 minutes（P<0.05）. On non-stimulated-side, a marked immediate increase was observed following tDCS， but subsequent trends were similar between the two methods， with no significant differences. Bilateral CMCT decreased after both types of stimulation， with no significant differences in changes over time between the two methods. Conclusion： tDCS has a more pronounced immediate effect on RMT modulation， while HD-tDCS exhibits more prominent delayed effects.