The effects of inhibitory and facilitatory intracortical circuits on interhemispheric inhibition in the human motor cortex
The effects of inhibitory and facilitatory intracortical circuits on interhemispheric inhibition in the human motor cortex
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DOI：
10.1113/jphysiol.2006.126011
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发表时间：
2007-05-01
影响因子：
5.5
通讯作者：
Chen, Robert
中科院分区：
文献类型：
--
作者：
Lee, Hubert;Gunraj, Carolyn;Chen, Robert
抑制性和易化性皮质内通路调节运动皮质输出可以在人类中用经颅磁刺激进行非侵入性研究。这些回路包括短间期皮层内抑制（SICI）、长间期皮层内抑制（LICI）和皮层内易化（ICF）。运动皮层的刺激也以短（类似于10 ms，IHI 10）或长间隔（类似于40 ms，IHI 40）抑制对侧运动皮层（半球间抑制，IHI）。我们研究了SICI，I CF和LICI如何影响IHI 10和IHI 40。我们假设皮层内回路对IHI和皮层输出神经元有相似的作用：SICI和LICI会降低IHI，ICF会增加IHI。我们将单独的IHI 10和IHI 40与在SICI、ICF或LICI存在下引起的IHI 10和IHI 40进行了比较。我们的结果表明，SICI和LICI减少IHI 10，IHI 40和皮质脊髓输出到相似的程度。ICF增加皮质脊髓输出量，但对IHI 10或IHI 40无影响。ICF对皮质脊髓兴奋性和IHI的不同影响表明，介导IHI和皮质脊髓输出系统的跨胼胝体纤维来自不同的神经元群体。SICI和LICI产生更多的全局抑制，对经胼胝体和下行皮质脊髓回路的影响相似。
Inhibitory and facilitatory intracortical pathways regulating motor cortical output can be studied non-invasively in humans with transcranial magnetic stimulation. These circuits include short-interval intracortical inhibition (SICI), long-interval intracortical inhibition (LICI) and intracortical facilitation (ICF). Stimulation of the motor cortex also inhibits the contralateral motor cortex (interhemispheric inhibition, IHI) at short (similar to 10 ms, IHI10) or long intervals (similar to 40 ms, IHI40). We investigated how SICI, I CF, and LICI influence IHI10 and IHI40. We hypothesize that intracortical circuits will have similar effects on IHI and cortical output neurons: SICI and LICI will decrease IHI, and ICF will increase it. Motor evoked potentials were recorded from the first dorsal interosseous muscles bilaterally in 10 healthy subjects. We compared IHI10 and IHI40 alone to IHI10 and IHI40 elicited in the presence of SICI, ICF, or LICI. Our results showed that SICI and LICI reduced IHI10, IHI40 and corticospinal output to a similar degree. ICF increased corticospinal output but had no effect on either IHI10 or IHI40. The different effects of ICF on corticospinal excitability and IHI suggest the transcallosal fibres mediating IHI and the corticospinal output system arise from different neuronal populations. SICI and LICI produce more global inhibition with similar effects on the transcallosal and descending corticospinal circuits.