Alterations in corticospinal excitability with imposed vs. voluntary fatigue in human hand muscles
Alterations in corticospinal excitability with imposed vs. voluntary fatigue in human hand muscles
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DOI：
10.1152/japplphysiol.00835.2001
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发表时间：
2002-05-01
影响因子：
3.3
通讯作者：
Miles, TS
中科院分区：
文献类型：
--
作者：
Pitcher, JB;Miles, TS
我们的目的是确定是否运动后抑郁的运动诱发电位（MEP）可以证明没有自愿肌肉激活的人。随意疲劳是由第一背侧骨间肌（FDI）的2分钟最大随意收缩（MVC）引起的。在另一种情况下，“电疲劳”诱导与列车的冲击交付2分钟以上的FDI电机点。12名受试者中有5名还经历了“顺序疲劳”，包括2分钟的WC FDI，然后休息20分钟，然后进行2分钟的运动点刺激。随意疲劳引起MEP抑郁症，持续至少20分钟。电疲劳引起短暂的MEP易化，消退后20分钟的刺激，并在30分钟内成为抑郁症。因此MEP抑郁症可以引起自愿和电疲劳。在电疲劳时，初始抑郁被短暂的MEP易化所“掩盖”，反映了长时间电刺激诱导的皮层可塑性。MEP抑制可能反映了来自运动肌肉的紧张性传入输入，其改变了皮质兴奋性而不改变脊髓兴奋性。
We aimed to determine whether postexercise depression of motor-evoked potentials (MEPs) could be demonstrated without voluntary muscle activation in humans. Voluntary fatigue was induced with a 2-min maximal voluntary contraction (MVC) of the first dorsal interosseous (FDI) muscle. On another occasion, "electrical fatigue" was induced with trains of shocks delivered for 2 min over the FDI motor point. Five of the twelve subjects also underwent "sequential fatigue" consisting of a 2-min WC of FDI followed by 20 min of rest and then 2 min of motor point stimulation. Voluntary fatigue induced MEP depression that persisted for at least 20 min. Electrical fatigue induced a transient MEP facilitation that subsided 20 min after the stimulation and became depressed within 30 min. Thus MEP depression can be induced by both voluntary and electrical fatigue. With electrical fatigue, the initial depression is "masked" by transient MEP facilitation, reflecting cortical plasticity induced by the prolonged electrical stimulation. MEP depression probably reflects tonic afferent input from the exercising muscle that alters cortical excitability without altering spinal excitability.