Shifting of activation center in the brain during muscle fatigue: An explanation of minimal central fatigue?
Shifting of activation center in the brain during muscle fatigue: An explanation of minimal central fatigue?
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DOI：
10.1016/j.neuroimage.2006.09.050
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发表时间：
2007-03-01
期刊：
影响因子：
5.7
通讯作者：
Yue, Guang H.
中科院分区：
文献类型：
--
作者：
Liu, Jing Z.;Lewandowski, Beth;Yue, Guang H.
越来越多的证据表明，控制自主运动任务的皮质激活的总体水平，导致显着的肌肉疲劳，并没有减少那么多的运动神经元池的激活水平投射到肌肉。这种“肌肉疲劳>皮层疲劳”现象的一个可能解释是，大脑是一个具有内置冗余的器官：它有多个运动中心和平行的通路，当前一个位置的神经元变得疲劳时，激活中心可能会从一个位置转移到另一个位置。通过估计疲劳和非疲劳运动任务中高密度（64通道）头皮脑电信号的源位置变化来验证这一假设。电流偶极子模型被用来估计EEG源。疲劳运动任务引起明显的肌肉疲劳，而非疲劳任务没有。表明大脑激活中心的EEG信号源在疲劳运动任务期间显示出实质性的位置偏移。这种变化不能用非疲劳任务EEG和模拟数据估计误差引起的源位置变化来解释。与非疲劳状态相比，疲劳状态下所有受试者的源位置的加权中心均向右半球（肌肉激活的同侧）、前部和下部皮质区域移动。疲劳并没有改变偶极子（源信号）的强度或大脑激活的整体水平。大脑可以通过转移参与疲劳运动任务的神经元群体来避免疲劳。(c)2006年爱思唯尔公司All rights reserved.
Accumulating evidence suggests that the overall level of cortical activation controlling a voluntary motor task that leads to significant muscle fatigue does not decrease as much as the activation level of the motoneuron pool projecting to the muscle. One possible explanation for this "muscle fatigue > cortical fatigue" phenomenon is that the brain is an organ with built-in redundancies: it has multiple motor centers and parallel pathways, and the center of activation may shift from one location to another when neurons in the previous location become fatigued. This hypothesis was tested by estimating the changes of source locations of high-density (64 channels) scalp electroencephalo-graphic (EEG) signals collected during both fatigue and non-fatigue motor tasks. A current dipole model was used to estimate the EEG sources. The fatigue motor task induced significant muscle fatigue, and the non-fatigue task did not. The EEG signal source that indicated the center of brain activation showed substantial location shifts during the fatigue motor task. The shifts could not be explained by variations of source locations caused by error estimated from the non-fatigue task EEG and simulated data. Compared to the non-fatigue condition, the weighted-center of the source locations for all the participants shifted toward the right hemisphere (ipsilateral to the muscle activation), anterior, and inferior cortical regions under the fatigue condition. Fatigue did not alter dipole (source-signal) strength or the overall level of brain activation. The brain may avoid fatigue by shifting neuron populations that participate in a fatiguing motor task. (c) 2006 Elsevier Inc. All rights reserved.