BACKGROUND Transcranial direct current stimulation (tDCS) has emerged as a non-invasive brain stimulation technique. Most studies show that anodal tDCS increases cortical excitability. However, this effect has been found to be highly variable. OBJECTIVE To test the effect of anodal tDCS on cortical excitability and the interaction effect of two participant-specific factors that may explain individual differences in sensitivity to anodal tDCS: the Brain Derived Neurotrophic Factor Val66Met polymorphism (BDNF genotype) and the latency difference between anterior-posterior and lateromedial TMS pulses (APLM latency). METHODS In 62 healthy participants, cortical excitability over the left motor cortex was measured before and after anodal tDCS at 2mA for 20 minutes in a pre-registered, double-blind, randomized, placebo-controlled trial with repeated measures. RESULTS We did not find a main effect of anodal tDCS, nor an interaction effect of the participant-specific predictors. Moreover, further analyses did not provide evidence for the existence of responders and non-responders. CONCLUSION This study indicates that anodal tDCS at 2mA for 20 minutes may not reliably affect cortical excitability.

中文翻译：

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在一项大型双盲安慰剂对照试验中，阳极 tDCS 对运动皮层兴奋性没有影响，也没有证据表明有反应者

背景技术经颅直流电刺激(tDCS) 已成为一种非侵入性脑刺激技术。大多数研究表明，阳极 tDCS 会增加皮质兴奋性。然而，已经发现这种影响是高度可变的。目的 测试阳极 tDCS 对皮层兴奋性的影响以及两个参与者特定因素的相互作用，这些因素可以解释对阳极 tDCS 敏感性的个体差异：脑源性神经营养因子 Val66Met 多态性（BDNF 基因型）和前-后和外侧 TMS 脉冲（APLM 潜伏期）。方法 在 62 名健康参与者中，在预先登记、双盲、随机、重复测量的安慰剂对照试验。结果 我们没有发现阳极 tDCS 的主要影响，也没有发现参与者特定预测因子的交互作用。此外，进一步的分析没有提供存在应答者和无应答者的证据。结论 本研究表明，2mA 下的阳极 tDCS 20 分钟可能无法可靠地影响皮质兴奋性。