Ipsilateral motor cortical responses to TMS during lengthening and shortening of the contralateral wrist flexors.
Ipsilateral motor cortical responses to TMS during lengthening and shortening of the contralateral wrist flexors.
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DOI：
10.1111/j.1460-9568.2010.07567.x
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发表时间：
2011-03
期刊：
影响因子：
--
通讯作者：
Hortobágyi T
中科院分区：
文献类型：
--
作者：
Howatson G;Taylor MB;Rider P;Motawar BR;McNally MP;Solnik S;DeVita P;Hortobágyi T
单侧延长收缩提供了一个更大的刺激神经肌肉适应比缩短收缩的活动和非活动对侧同源肌肉，虽然鲜为人知的潜在机制。在这里，我们研究的可能性，皮质脊髓和脊髓兴奋性变化的收缩特异性的方式在放松的右桡侧腕屈肌（FCR）时，人类执行单边延长和缩短收缩的左腕屈肌在相同的绝对力。在最大自主收缩（MVC）的80%和100%时，放松的右侧FCR的皮质脊髓兴奋性在延长过程中比缩短过程中增加更多。短间隔皮质内抑制（SICI）在缩短收缩期间减弱，在延长期间几乎消失。皮质内易化（ICF）减少缩短，但增加延长。大脑半球间抑制（IHI）的“非活性”运动皮层减少缩短期间，并在延长90%MVC几乎被废除。在放松的右FCR的H反射的幅度下降，并保持压抑20秒后延长和缩短的左腕屈肌。我们讨论的可能性，而不是增加传入输入，下降的运动命令和激活的大脑区域，链接功能的运动皮层在肌肉延长与缩短的差异可能会导致同侧运动皮层输出的收缩特异性调制。总之，同侧M1的TMS反应是收缩特异性的;单侧延长和缩短收缩降低对侧脊髓兴奋性，但独特调制同侧皮质脊髓兴奋性和网络参与皮质内和半球间的连接，这可能具有临床意义。
Unilateral lengthening contractions provide a greater stimulus for neuromuscular adaptation than shortening contractions in the active and non-active contralateral homologous muscle, although little is known of the potential mechanism. Here we examined the possibility that corticospinal and spinal excitability vary in a contraction-specific manner in the relaxed right flexor carpi radialis (FCR) when humans perform unilateral lengthening and shortening contractions of the left wrist flexors at the same absolute force. Corticospinal excitability in the relaxed right FCR increased more during lengthening than shortening at 80 and 100% of maximum voluntary contraction (MVC). Short-interval intracortical inhibition (SICI) diminished during shortening contractions and it became nearly abolished during lengthening. Intracortical facilitation (ICF) lessened during shortening but increased during lengthening. Interhemispheric inhibition (IHI) to the “non-active” motor cortex diminished during shortening and became nearly abolished during lengthening at 90% MVC. The amplitude of the H-reflex in the relaxed right FCR decreased during and remained depressed for 20 s after lengthening and shortening of the left wrist flexors. We discuss the possibility that instead of the increased afferent input, differences in the descending motor command and activation of brain areas that link function of the motor cortices during muscle lengthening vs. shortening may cause the contraction-specific modulation of ipsilateral motor cortical output. In conclusion, ipsilateral M1 responses to TMS are contraction-specific; unilateral lengthening and shortening contractions reduced contralateral spinal excitability but uniquely modulated ipsilateral corticospinal excitability and the networks involved in intracortical and interhemispheric connections, which may have clinical implications.
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影响因子：
2.5
作者：
Housh, TJ;Housh, DJ;Weir, LL
通讯作者：
Weir, LL
DOI：
10.1097/00005768-199701000-00015
发表时间：
1997-01-01
期刊：
MEDICINE AND SCIENCE IN SPORTS AND EXERCISE
影响因子：
--
作者：
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通讯作者：
Hill, JP
影响因子：
5.5
作者：
Gerloff, C;Cohen, LG;Hallett, M
通讯作者：
Hallett, M
影响因子：
5.5
作者：
Avanzino, L.;Teo, J. T. H.;Rothwell, J. C.
通讯作者：
Rothwell, J. C.
影响因子：
2.5
作者：
Fang, Y;Siemionow, V;Yue, GH
通讯作者：
Yue, GH