Effect of muse I e fat i gue and motor I earn i hg on p I ast i c changes of motor and sensory cortices in cerebrum

我们研究了肌肉疲劳和运动学习对大脑运动皮质和感觉皮质可塑性变化的影响。我们的结果将显示在下面；(1)两次10 min短打字和一次2 min抓握疲劳的组合较容易引起恢复期短间隔皮质内抑制（SICI）的降低，但两次或一次抓握疲劳对SICI没有影响，而下一阶段抓握疲劳后的第二次打字速度较第一次有所提高；通过脑电图或外周电刺激（PES）与经颅磁刺激（TMS）相结合的方法，研究了一次抓握疲劳和/或两次打字练习的感觉兴奋性对运动皮层可塑性变化的影响，发现短时间打字练习没有改变感觉诱发电位（SEP）的Psoo，但抓握疲劳在之后有立即降低Psoo的趋势，并在10 min后恢复。3)两种打字练习和抓握疲劳的结合对PES和TMS的短传入抑制（SAI）和长传入抑制（LAI）没有影响。肌疲劳对脑电SEP和感觉皮层SAI、LAI的影响不同。我们发现SICI的解除抑制与运动皮层可塑性变化一样，直接依赖于肌肉疲劳和手指控制练习，但这种解除抑制不受疲劳和控制任务引起的外周感觉兴奋性变化的影响。肌肉疲劳和运动学习的结合似乎对运动皮层的可塑性变化是有效的。

We examined how muscle fatigue and motor learning as typing influenced plastic changes of motor and sensory cortices in cerebrum. Our results were to be shown below that ; 1) the combination of two short typing practices for ten min. and a gripping fatigue for two min. relatively easily induced the decrease of short-interval intracortical inhibition(SICI) during recovery period although only two typing practices or only a gripping fatigue did not change SICI and the second typing velocity after gripping fatigue enhanced compared with the first one, 2) on next stage, we tried how sensory excitability by a gripping fatigue and/or two typing practices contributed to plastic changes in motor cortex by using EEG or the combination of peripheral electric stimulation(PES) and TMS, and the short typing practice did not change Psoo in sensory evoked potential(SEP) but the gripping fatigue trended to decrease Psoo immediately after it and recovered until 10 min, and 3) the combination of two typing practices and a gripping fatigue did not change short afferent inhibition(SAI) and long afferent inhibition(LAI) by PES and TMS. Muscle fatigue gave the different effects between SEP in EEG and SAI and LAI in sensory cortex. Our finding was that the disinhibition of SICI like plastic change in motor cortex directly depended on muscle fatigue and fingers control practice but this disinhibition would be not influenced by changes of peripheral sensory excitability due to fatigue and control tasks. It is seemed that the combination of muscle fatigue and motor learning would be effective at getting plastic change in motor cortex.