Comparison between short train, monophasic and biphasic repetitive transcranial magnetic stimulation (rTMS) of the human motor cortex
Comparison between short train, monophasic and biphasic repetitive transcranial magnetic stimulation (rTMS) of the human motor cortex
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DOI：
10.1016/j.clinph.2004.09.020
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发表时间：
2005-03-01
影响因子：
4.7
通讯作者：
Ugawa, Y
中科院分区：
文献类型：
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作者：
Arai, N;Okabe, S;Ugawa, Y
目的：比较短训练、单相、重复经颅磁刺激 (rTMS) 与短训练、双相 rTMS 引起的运动诱发电位 (MEP)。方法：受试者为 13 名健康志愿者。在几种不同的刺激条件下记录右第一背侧骨间肌（FDI）的表面肌电（EMG）反应。我们以 0.5、1、2 或 3 Hz 的频率对运动皮层进行单相和双相 rTMS。为了研究脊髓的兴奋性变化，我们还在枕骨大孔水平进行了 3 Hz rTMS [Ukawa Y、Uesaka Y、Terao Y、Hanajima R、Kanazawa I。人类枕骨大孔水平皮质脊髓通路的磁刺激。安·尼罗尔 1994 年；36：618-24]。我们测量了在不同刺激条件下记录的 20 个 MEP 的大小和潜伏期。结果：使用单相或双相脉冲的 2 或 3 Hz 刺激会诱发 MEP，其幅度逐渐增加，且后面的 MEP 明显大于前面的 MEP。单相 rTMS 比双相刺激显示出更多的促进作用，特别是在 3 Hz 时。 3 Hz 枕骨大孔水平的刺激引起了相当恒定的 MEP。结论：皮质 MEP 的增强，而对枕骨大孔水平刺激的反应没有变化，表明促进发生在运动皮层。我们假设单相 TMS 在重复刺激过程中比双相 TMS 具有更强的短期效应，因为单相脉冲优先激活朝同一方向定向的一组神经元，以便它们的效应很容易叠加。相反，双相脉冲可能会激活多个不同的神经元群（促进性和抑制性），因此效果的总和不像单相脉冲那么清楚。然而，当施加单一刺激时，双相 TMS 被认为比单相 TMS 更强大，因为当使用相同强度的刺激（刺激器存储相同量的电流）时，刺激脉冲的峰峰值幅度更高且持续时间更长。意义：这意味着当使用 rTMS 作为治疗工具或在研究领域时，磁脉冲波形的差异 （单相或双相）可能会影响结果。 (c) 2004 年国际临床神经生理学联合会。由爱思唯尔爱尔兰有限公司出版。保留所有权利。
Objective: To compare motor evoked potentials (MEPs) elicited by short train, monophasic, repetitive transcranial magnetic stimulations (rTMS) with those by short train, biphasic rTMS.Methods: Subjects were 13 healthy volunteers. Surface electromyographic (EMG) responses were recorded from the right first dorsal interosseous muscle (FDI) in several different stimulation conditions. We gave both monophasic and biphasic rTMS over the motor cortex at a frequency of 0.5, 1, 2 or 3 Hz. To study excitability changes of the spinal cord, we also performed 3 Hz rTMS at the foramen magnum level [Ugawa Y, Uesaka Y, Terao Y, Hanajima R, Kanazawa I. Magnetic stimulation of corticospinal pathways at the foramen magnum level in humans. Ann Neurol 1994;36:618-24]. We measured the size and latency of each of 20 MEPs recorded in the different stimulation conditions.Results: 2 or 3 Hz stimulation with either monophasic or biphasic pulses evoked MEPs that gradually increased in amplitude with the later MEPs being significantly larger than the earlier ones. Monophasic rTMS showed much more facilitation than biphasic stimulation, particularly at 3 Hz. Stimulation at the foramen magnum level at 3 Hz elicited fairly constant MEPs.Conclusions: The enhancement of cortical MEPs with no changes of responses to foramen magnum level stimulation suggests that the facilitation occurred at the motor cortex. We hypothesize that monophasic TMS has a stronger short-term effect during repetitive stimulation than biphasic TMS because monophasic pulses preferentially activate one population of neurons oriented in the same direction so that their effects readily summate. Biphasic pulses in contrast may activate several different populations of neurons (both facilitatory and inhibitory) so that summation of the effects is not so clear as with monophasic pulses. When single stimuli are applied, however, biphasic TMS is thought to be more powerful than monophasic TMS because the peak-to-peak amplitude of stimulus pulse is higher and its duration is longer when the same intensity of stimulation (the same amount of current is stored by the stimulator) is used.Significance: This means that when using rTMS as a therapeutic tool or in research fields, the difference in waveforms of magnetic pulses (monophasic or biphasic) may affect the results. (c) 2004 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.