Decreased corticospinal excitability after subthreshold 1 Hz rTMS over lateral premotor cortex
Decreased corticospinal excitability after subthreshold 1 Hz rTMS over lateral premotor cortex
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DOI：
10.1212/wnl.57.3.449
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发表时间：
2001-08-14
期刊：
影响因子：
9.9
通讯作者：
Rothwell, JC
中科院分区：
文献类型：
--
作者：
Gerschlager, W;Siebner, HR;Rothwell, JC
目的：研究阈下1hz重复经颅磁刺激（rTMS）对运动前皮层、前额叶皮层和顶叶皮层是否能产生持续时间较长的运动皮层兴奋性变化。背景：长时间的1hz rTMS在运动皮层可以抑制运动诱发电位（MEP）的振幅在火车结束后的几分钟。由于rms不仅可以对刺激部位产生影响，还可以对其投射的远端部位产生影响，因此作者提出，对与运动皮层相连的远端部位的长时间刺激是否也会导致MEP的持久变化。方法：8名受试者在4天内分别在左侧外侧额叶皮层、左侧外侧运动前皮层、左侧运动皮层手部区和左侧前顶叶皮层分别接受1500次1 Hz的磁刺激。刺激强度设为90%，主动运动阈值。在条件训练前、训练中和训练后，通过测量单次阈上刺激在左运动手区引起的右第一背骨间肌MEP的振幅来探测皮质脊髓兴奋性。结果：左运动前皮质rTMS抑制右第一背骨间肌MEP振幅。这种效果在900次脉冲后达到最大（大约50%的抑制），并且在1500次刺激的整个训练中持续至少15分钟。在其他部位调节rTMS并没有改变MEP的大小。对照实验显示，左运动前皮层条件反射对左第一背骨间肌诱发的MEP无影响。结论：左侧运动前皮质阈下1hz rTMS诱导同侧运动皮质手区皮质脊髓兴奋性的短期抑制。这可能为研究健康人与运动障碍患者运动前皮层与运动皮层之间的功能相互作用提供一个模型。
Objective: To study whether trains of subthreshold 1 Hz repetitive transcranial magnetic stimulation (rTMS) over premotor, prefrontal, or parietal cortex can produce changes in excitability of motor cortex that outlast the application of the train. Background: Prolonged 1 Hz rTMS over the motor cortex can suppress the amplitude of motor-evoked potentials (MEP) for several minutes after the end of the train. Because,rms can produce effects not only at the site of stimulation but also at distant sites to which it projects, the authors asked whether prolonged stimulation of sites distant but connected to motor cortex can also lead to lasting changes in MEP. Methods: Eight subjects received 1500 magnetic stimuli given at I Hz over the left lateral frontal cortex, the left lateral premotor cortex, the hand area of the left motor cortex, and the left anterior parietal cortex on four separate days. Stimulus intensity was set at 90%, active motor threshold. Corticospinal excitability was probed by measuring the amplitude of MEP evoked in the right first dorsal interosseous muscle by single suprathreshold stimuli over the left motor hand area before, during, and after the conditioning trains. Results: rTMS over the left premotor cortex suppressed the amplitude of MEP in the right first dorsal interosseous muscle. The effect was maximized (approximately 50% suppression) after 900 pulses and outlasted the full train of 1500 stimuli for at least 15 minutes. Conditioning rTMS over the other sites did not modify the size of MEP. A control experiment showed that left premotor cortex conditioning had no effect on MEP evoked in the left first dorsal interosseous muscle. Conclusions: Subthreshold 1 Hz rTMS of the left premotor cortex induces a short-lasting inhibition of corticospinal excitability in the hand area of the ipsilateral motor cortex. This may provide a model for studying the functional interaction between premotor and motor cortex in healthy subjects and patients with movement disorders.