Interhemispheric plasticity in humans.
Interhemispheric plasticity in humans.
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DOI：
10.1249/mss.0b013e31820a94b8
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发表时间：
2011-07
影响因子：
4.1
通讯作者：
Hallett M
中科院分区：
文献类型：
--
作者：
Hortobágyi T;Richardson SP;Lomarev M;Shamim E;Meunier S;Russman H;Dang N;Hallett M
慢性单手运动练习不仅增加了训练肌的运动输出，而且增加了对肢未运动的同种肌的运动输出。我们检验了未经训练的初级运动皮层（iM1）的运动皮质兴奋性的适应和从训练到非训练M1的半球间抑制（IHI）介导了这种肢体间交叉教育的假设。健康的年轻志愿者（n = 12）在20次训练中以80%的强度进行了1000次右第一背骨间肌自主收缩（FDI）。受过培训的FDI的MVC增加了49.9%，未受过培训的FDI的MVC增加了28.1%。虽然在每5次训练前后用磁脑刺激（TMS）测量的iM1皮质脊髓兴奋性在休息时增加了6%，但这些变化与皮质内抑制和促进的变化一样，与交叉教育无关。在右侧FDI肌肉收缩弱和强的背景下分别给予弱和强的iM1经颅磁刺激，20次后iM1的兴奋性显著增加。IHI在治疗期间急性下降8.9%，在20次治疗期间慢性下降30.9%，这些慢性下降逐渐与交叉教育密切相关。训练组左ADM的力量和经颅磁刺激测量没有变化，非运动对照组也没有变化（n = 8）。这一发现为大脑半球间连接的可塑性提供了第一个证据，以调解由简单的运动任务产生的交叉教育。
Chronic unimanual motor practice increases the motor output not only in the trained but also in the non-exercised homologous muscle in the opposite limb. We examined the hypothesis that adaptations in motor cortical excitability of the non-trained primary motor cortex (iM1) and in interhemispheric inhibition (IHI) from the trained to the non-trained M1 mediate this inter-limb cross education. Healthy, young volunteers (n = 12) performed 1000 submaximal voluntary contractions (MVC) of the right first dorsal interosseus (FDI) at 80% MVC over 20 sessions. Trained FDI’s MVC increased 49.9% and the untrained FDI’s MVC increased 28.1%. Although corticospinal excitability in iM1, measured with magnetic brain stimulation (TMS) before and after every 5th session, increased 6% at rest, these changes, as those in intracortical inhibition and facilitation, did not correlate with cross education. When weak and strong TMS of iM1 were, respectively, delivered on a background of a weak and strong muscle contraction of the right FDI, excitability of iM1 increased dramatically after 20 sessions. IHI decreased 8.9% acutely within sessions and 30.9% chronically over 20 sessions and these chronic reductions progressively became more strongly associated with cross education. There were no changes in force or TMS measures in the trained group’s left ADM nor were there changes in a non-exercising control group (n = 8). The findings provide the first evidence for plasticity of interhemispheric connections to mediate cross education produced by a simple motor task.