Ziemann U, Tergau F, Wischer S, Hildebrandt J, Paulus W
Department of Clinical Neurophysiology, University of Göttingen, Germany.
Electroencephalogr Clin Neurophysiol. 1998 Aug;109(4):321-30. doi: 10.1016/s0924-980x(98)00023-x.
A novel paired transcranial magnetic stimulation (TMS) paradigm with a suprathreshold first and a subthreshold second stimulus was used in healthy volunteers to investigate the acute effects of a single oral dose of various CNS-active drugs on short-interval motor evoked potential (MEP) facilitation. MEPs were recorded from the relaxed abductor digiti muscle. Three peaks of MEP facilitation were consistently observed at interstimulus intervals of 1.1-1.5 ms, 2.3-2.7 ms, and 3.9-4.5 ms. The size of these MEP peaks was transiently suppressed by drugs which enhance gamma-aminobutyric acid (GABA) function in the neocortex (lorazepam, vigabatrin, phenobarbital, ethanol), while the GABA-B receptor agonist baclofen, anti-glutamate drugs (gabapentin, memantine), and sodium channel blockers (carbamazepine, lamotrigine) had no effect. The interstimulus intervals effective for the production of the MEP peaks remained unaffected by all drugs. The MEP peaks are thought to be due to a facilitatory interaction of I-(indirect) waves in the motor cortex. Therefore, the present results indicate that the production of I-waves is primarily controlled by GABA related neuronal circuits. The potential relevance of this non-invasive paired TMS protocol for the investigation of I-waves in patients with neurological disease will be discussed.
在健康志愿者中使用了一种新型的配对经颅磁刺激（TMS）范式，即第一个刺激为阈上刺激，第二个刺激为阈下刺激，以研究单次口服各种中枢神经系统活性药物对短间隔运动诱发电位（MEP）易化的急性影响。从放松的小指展肌记录MEP。在刺激间隔为1.1 - 1.5毫秒、2.3 - 2.7毫秒和3.9 - 4.5毫秒时，始终观察到MEP易化的三个峰值。这些MEP峰值的大小被增强新皮层中γ-氨基丁酸（GABA）功能的药物（劳拉西泮、氨己烯酸、苯巴比妥、乙醇）短暂抑制，而GABA-B受体激动剂巴氯芬、抗谷氨酸药物（加巴喷丁、美金刚）和钠通道阻滞剂（卡马西平、拉莫三嗪）则没有影响。对产生MEP峰值有效的刺激间隔不受所有药物影响。MEP峰值被认为是由于运动皮层中I -（间接）波的易化相互作用。因此，目前的结果表明I波的产生主要受GABA相关神经元回路控制。将讨论这种非侵入性配对TMS方案在神经疾病患者I波研究中的潜在相关性。
