The Interaction With Task-induced Activity is More Important Than Polarization: A tDCS Study
The Interaction With Task-induced Activity is More Important Than Polarization: A tDCS Study
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DOI：
10.1016/j.brs.2014.11.006
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发表时间：
2015-03-01
影响因子：
7.7
通讯作者：
Miniussi, Carlo
中科院分区：
文献类型：
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作者：
Bortoletto, Marta;Pellicciari, Maria Concetta;Miniussi, Carlo
背景：经颅阳极直流电刺激(A-tDC)是一种非侵入性技术，可通过调节神经可塑性来利用皮质极化来增加兴奋性和促进学习。虽然A-tDC的促进作用已经得到了很好的证明，但有证据表明它们并不总是存在的，甚至可能在任务执行过程中被逆转。目的：在本研究中，我们探索了A-tDC与任务执行之间的交互作用。方法：采用A-tDCs或对照刺激(Ctrl)与两种运动训练(MP)相结合的实验，一种是诱导学习增强皮质兴奋性(F-MP)，另一种是不诱导学习也不改变皮质兴奋性(S-MP)。在刺激初级运动皮质的同时，进行6个MP区的刺激。此外，在刺激前(基线)和刺激后各进行一次F-MP阻断。在另一项实验中，在基线阻断前(TMS-PRE)和MP后(TMS-POST)记录运动诱发电位(MEP)。结果：我们观察到，当参与者进行F-MP时，A-tDCs减少了学习，并促进了对S-MP的学习。MEPS数据与行为学结果相吻合，证实了A-tDCs产生的效应依赖于任务诱发的兴奋性变化。结论：我们的结果表明，tDCs诱导的可塑性是任务依赖性的，A-tDCs与另一兴奋性增加事件(如运动练习)的同时结合可能触发非加性机制，从而阻碍神经可塑性。(C)2015 Elsevier Inc.保留所有权利。
Background: Anodal transcranial direct current stimulation (A-tDCS) is a non-invasive technique in which cortical polarization can be used to increase excitability and facilitate learning through the modulation of neuroplasticity. Although the facilitatory effects of A-tDCS are well documented, there is evidence that they are not always present and may even be reversed during task execution.Objective: In this study, we explored the interaction between A-tDCS and task execution. We aimed to test how the excitability induced by the task interacts with the excitability induced by A-tDCS and determines the behavioral outcome.Methods: We performed an experiment in which A-tDCS or a control stimulation (Ctrl) were combined with one of two motor practices (MP), one inducing learning and increasing cortical excitability (F-MP) and the other neither inducing learning nor changing cortical excitability (S-MP). Six blocks of MP were performed while the primary motor cortex was stimulated. Moreover, one block of F-MP was performed before the stimulation (baseline) and one after. In an additional experiment, motor evoked potentials (MEPs) were recorded before the baseline block (TMS-pre) and after the MP (TMS-post).Results: We observed that A-tDCS reduced learning when participants performed the F-MP and facilitated learning for the S-MP. MEPs data paralleled behavioral results, confirming that the effects generated by A-tDCS depend on the excitability changes induced by the task.Conclusions: Our results demonstrate that tDCS-induced plasticity is task-dependent, and the concurrent combination of A-tDCS with another excitability-increasing event, e.g., motor practice, may trigger non-additive mechanisms, hindering neuroplasticity. (C) 2015 Elsevier Inc. All rights reserved.