Short and long duration transcranial direct current stimulation (tDCS) over the human hand motor area
Short and long duration transcranial direct current stimulation (tDCS) over the human hand motor area
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DOI：
10.1007/s00221-007-1149-z
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发表时间：
2008-02-01
影响因子：
2
通讯作者：
Ugawa, Yoshikazu
中科院分区：
文献类型：
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作者：
Furubayashi, Toshiaki;Terao, Yasuo;Ugawa, Yoshikazu
本研究旨在研究短时和长时经颅直流电刺激（tDCS）对人运动皮层的影响。在8名正常志愿者中，由经颅磁刺激（TMS）记录右侧第一骨间背侧肌诱发的运动诱发电位（MEP），并在左侧初级运动皮层（M1）和对侧眼眶上方给予tDCS电极。我们进行了两个实验：一个用于短持续时间tDCS（100 ms，1，3或5 mA），另一个用于长持续时间tDCS（10 min，1 mA）。tDCS和TMS的刺激起始间隔（SOA）分别为1-7和10-120 ms。在后一实验中，在10 min tDCS结束后0-20 min给予TMS。我们通过比较由tDCS与对照MEP调节的MEP来评估tDCS对运动皮层的影响。当强度等于或大于3 mA时，阴极短持续时间tDCS显著降低了在1-7 ms的SOA处对运动皮层刺激的反应的大小。3 mA条件刺激时，短时tDCS可显著增加MEP，而5 mA条件刺激时无此作用。此外，委员会认为，阳极和阴极短持续时间tDCS在SOAs为20- 30时均显著降低对TMS的反应。长时程阴极tDCS使tDCS偏移后0和5 min的MEP降低，阳极tDCS使tDCS偏移后1和15 min的MEP升高。我们得出结论，SOA小于10 ms时的效应主要是由由tDCS诱导的静息膜电位。在20-100 ms的SOA处的效应被认为是由头皮处的皮肤感觉激活产生的惊吓样反应的非特异性效应。长持续时间tDCS引起的效应可能是短时程增强或抑郁样效应。
The aim of the present paper is to study effects of short and long duration transcranial direct current stimulation (tDCS) on the human motor cortex. In eight normal volunteers, motor evoked potentials (MEPs) induced by transcranial magnetic stimulation (TMS) were recorded from the right first dorsal interosseous muscle, and tDCS was given with electrodes over the left primary motor cortex (M1) and the contralateral orbit. We performed two experiments: one for short duration tDCS (100 ms, 1, 3 or 5 mA) and the other for long duration tDCS (10 min, 1 mA). The stimulus onset asynchrony (SOA) between the onset of tDCS and TMS were 1-7 and 10-120 ms for the former experiment. In the latter experiment, TMS was given 0-20 min after the end of 10 min tDCS. We evaluated the effect of tDCS on the motor cortex by comparing MEPs conditioned by tDCS with control MEPs. Cathodal short duration tDCS significantly reduced the size of responses to motor cortical stimulation at SOAs of 1-7 ms when the intensity was equal to or greater than 3 mA. Anodal short duration tDCS significantly increased MEPs when the intensity was 3 mA, but the enhancement did not occur when using 5 mA conditioning stimulus. Moreover, both anodal and cathodal short duration tDCS decreased responses to TMS significantly at SOAs of 20-50 ms and enhanced them at an SOA of 90 ms. Long duration cathodal tDCS decreased MEPs at 0 and 5 min after the offset of tDCS and anodal long duration tDCS increased them at 1 and 15 min. We conclude that the effect at SOAs less than 10 ms is mainly caused by acute changes in resting membrane potential induced by tDCS. The effect at SOAs of 20-100 ms is considered to be a nonspecific effect of a startle-like response produced by activation of skin sensation at the scalp. The effect provoked by long duration tDCS may be short-term potentiation or depression like effects.