Inhibitory interactions between pairs of subthreshold conditioning stimuli in the human motor cortex
Inhibitory interactions between pairs of subthreshold conditioning stimuli in the human motor cortex
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DOI：
10.1016/j.clinph.2003.11.002
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发表时间：
2004-04-01
影响因子：
4.7
通讯作者：
Rothwell, JC
中科院分区：
文献类型：
--
作者：
Bestmann, S;Siebner, HR;Rothwell, JC
目的：研究短间隔成对脉冲对皮层内抑制（ICI）和易化（ICF）的影响。我们测试是否对阈下条件刺激相互作用，以及它们是否表现出快速的周期性类似于阈下I-波interaction.Methods：经颅磁刺激（TMS）中观察到的左M I引起的运动诱发电位（MEP）约I mV峰-峰振幅在对侧第一背侧骨间（FDI）肌肉。每次测试电击（TS）之前，以短的刺激间隔（ISI 1-15 ms）进行单个或成对的阈下条件刺激（CS 1和CS2）。结果：CS单次对MEP无影响，而CS 1双次对MEP有明显的抑制作用。在CS2-TS间期为2 ms的情况下，如果在CS2之前1-2.5 ms应用CS 1，则出现最大抑制。这种抑制作用逐渐减弱的CS2-CS 1的间隔增加到13毫秒。当促进存在与CSsingle-TS间隔为10毫秒，一个小的，但不显着的额外的促进发生在ISI之间的CS2和CS 1的6-15毫秒。结论：两个阈下条件刺激促进抑制，缺乏快速的周期性典型的I波相互作用。这些数据将与突触输入集中在一个共同的抑制性中间神经元上的模型兼容。(C)2004年国际临床神经生理学联合会。由Elsevier爱尔兰有限公司出版。保留所有权利。
Objective: These experiments examined short interval paired-pulse paradigms for intracortical inhibition (ICI) and facilitation (ICF). We tested whether pairs of subthreshold conditioning stimuli interact, and whether they showed rapid periodicity similar to that observed in subthreshold I-wave interaction.Methods: Transcranial magnetic stimulation (TMS) was given over left M I to evoke a motor-evoked potential (MEP) of approximately I mV peak-to-peak amplitude in the contralateral first dorsal interosseous (FDI) muscle. Each test shock (TS) was preceded by single or paired subthreshold conditioning stimuli (CS1 and CS2) at short interstimulus intervals (ISIs 1-15 ms). Intensities of CS were set just below thresholds for intracortical inhibition (ICI) or intracortical facilitation (ICF).Results: Each CSsingle alone had no effect on the test MEP, but with two CS1 clear inhibition was elicited at certain intervals. With a CS2-TS interval of 2 ms, maximum suppression occurred if CS1 was applied 1-2.5 ms before CS2. This inhibitory effect tapered off gradually as the CS2-CS1 interval was increased up to 13 ms. When facilitation was present with a CSsingle-TS interval of 10 ms, a small but nonsignificant extra-facilitation occurred at ISIs between CS2 and CS1 of 6-15 ms.Conclusions: Two subthreshold conditioning stimuli facilitate inhibition that lacks the rapid periodicity typical of I-wave interaction. The data would be compatible with a model in which synaptic inputs converge on a common inhibitory interneurone. (C) 2004 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.