Polarity-independent effects of tDCS on paired associative stimulation-induced plasticity
Polarity-independent effects of tDCS on paired associative stimulation-induced plasticity
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DOI：
10.1016/j.brs.2017.07.010
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发表时间：
2017-11-01
影响因子：
7.7
通讯作者：
Ziemann, Ulf
中科院分区：
文献类型：
--
作者：
Faber, Hanna;Opitz, Alexander;Ziemann, Ulf
背景资料：经颅直流电刺激（Transcranial direct current stimulation，tDCS）可以刺激人脑皮层。目的/假设：我们试图验证这样一个假设，即初级运动皮层（M1）的后前（PA）而不是前后（AP）tDCS与由成对的联合刺激辅助运动区（SMA）诱导的皮质脊髓可塑性产生协同效应。方法：在15名健康成人中以双盲、随机交叉设计测试三种实验条件：导航PAS（SMA -> M1）在PA-tDCS期间（35 cm（2）电极，阳极位于M1手部区域后方3 cm，阴极位于对侧额极皮质上方，1 mA，2 x 5 min）或AP-tDCS（反极性）或假手术-tDCS。结果：tDCS对PAS（SMA -> M1）诱导的可塑性无显著影响。然而，事后受试者内对比显示了显著的tDCS与PAS（SMA -> M1）相互作用。这可以通过PA-tDCS和AP-tDCS在13/15例受试者中将PAS（SMA -> M1）效应改变为相同方向来解释（87%，偏离相等的p = 0.004）。PA-tDCS和AP-tDCS效应的大小相关（r（s）= 0.53，p = 0.044）。对照实验表明，PA-tDCS和AP-tDCS单独（没有PAS（SMA -> M1））没有影响MEP amplitude.Conclusions：数据点PAS（SMA -> M1）诱导的可塑性的单向tDCS的影响，无论tDCS极性，与我们的假设相反。我们认为皮质柱的径向对称性、运动皮质的回状结构和可塑性诱导的协同性可以解释这一发现。(C)2017爱思唯尔公司All rights reserved.
Background: Transcranial direct current stimulation (tDCS) can polarize the cortex of the human brain.Objective/Hypothesis: We sought to verify the hypothesis that posterior-anterior (PA) but not anteriorposterior (AP) tDCS of primary motor cortex (M1) produces cooperative effects with corticospinal plasticity induced by paired associative stimulation of the supplementary motor area (SMA) to M1 projection (PAS(SMA -> M1)) in a highly controlled experimental design.Methods: Three experimental conditions were tested in a double-blinded, randomized crossover design in 15 healthy adults: Navigated PAS(SMA -> M1) during PA-tDCS (35 cm(2) electrodes, anode 3 cm posterior to M1 hand area, cathode over contralateral frontopolar cortex, 1 mA, 2 x 5 min) or AP-tDCS (reversed polarity), or sham-tDCS. Effects were analyzed over 120 min post-intervention by changes of motor evoked potential (MEP) amplitude in a hand muscle.Results: There was no significant effect of tDCS on PAS(SMA -> M1) induced plasticity in the repeated-measures ANOVA. However, post-hoc within-subject contrasts revealed a significant tDCS with PAS(SMA -> M1) interaction. This was explained by PA-tDCS and AP-tDCS modifying the PAS(SMA -> M1) effect into the same direction in 13/15 subjects (87%, p = 0.004 for deviation from equality). Sizes of the PA-tDCS and AP-tDCS effects were correlated (r(s) = 0.53, p = 0.044). A control experiment demonstrated that PA-tDCS and AP-tDCS alone (without PAS(SMA -> M1)) had no effect on MEP amplitude.Conclusions: Data point to unidirectional tDCS effects on PAS(SMA -> M1) induced plasticity irrespective of tDCS polarity, in contrast to our hypothesis. We propose that radial symmetry of cortical columns, gyral geometry of motor cortex, and cooperativity of plasticity induction can explain the findings. (C) 2017 Elsevier Inc. All rights reserved.