Contributions to muscle force and EMG by combined neural excitation and electrical stimulation.
Contributions to muscle force and EMG by combined neural excitation and electrical stimulation.
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DOI：
10.1088/1741-2560/11/5/056022
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发表时间：
2014-10
影响因子：
4
通讯作者：
Cole NM
中科院分区：
文献类型：
--
作者：
Crago PE;Makowski NS;Cole NM
用于研究或临床干预的肌肉刺激通常叠加在正在进行的生理活动上，而没有定量了解刺激对净肌肉活动和生理反应的影响。实验研究表明，在刺激过程中的总力小于孤立的自愿和刺激力的总和，但闭塞机制尚不清楚。我们开发了一个模型的传出运动活动引起的叠加刺激在生理激活的收缩。该模型结合了动作电位的相互作用，由于碰撞块，源重置，和不应期与先前发表的模型的生理运动单位招聘，速率调制，力的产生，和EMG生成在人类第一背侧骨间肌的机制和有效性的净肌肉力量和EMG的刺激。在生理收缩期间的刺激证明了力和EMG的神经分量的部分闭塞，这是由于由两个源激活的运动单元中的动作电位相互作用。根据神经和刺激放电率以及力-频率特性，单个运动单元的力可以更大、更小或不受刺激影响。相反，同时刺激运动单位的自主运动单位EMG电位随着刺激速率的增加而显示出进行性闭塞。模拟预测闭塞将通过反向刺激募集顺序来减少。结果是一致的，并提供了一个机械的解释以前发表的实验证据的力闭塞。该模型还预测了两种以前没有报道过的效果-自愿EMG闭塞和近端刺激部位的优势。这项研究为未来的实验和涉及运动或感觉刺激的临床神经假体干预的合理设计提供了基础。
Stimulation of muscle for research or clinical interventions is often superimposed on ongoing physiological activity, without a quantitative understanding of the impact of the stimulation on the net muscle activity and the physiological response. Experimental studies show that total force during stimulation is less than the sum of the isolated voluntary and stimulated forces, but the occlusion mechanism is not understood. We develop a model of efferent motor activity elicited by superimposing stimulation during a physiologically activated contraction. The model combines action potential interactions due to collision block, source resetting, and refractory periods with previously published models of physiological motor unit recruitment, rate modulation, force production, and EMG generation in human first dorsal interosseous muscle to investigate the mechanisms and effectiveness of stimulation on the net muscle force and EMG. Stimulation during a physiological contraction demonstrates partial occlusion of force and the neural component of the EMG, due to action potential interactions in motor units activated by both sources. Depending on neural and stimulation firing rates as well as on force-frequency properties, individual motor unit forces can be greater, smaller, or unchanged by the stimulation. In contrast, voluntary motor unit EMG potentials in simultaneously stimulated motor units show progressive occlusion with increasing stimulus rate. The simulations predict that occlusion would be decreased by a reverse stimulation recruitment order. The results are consistent with and provide a mechanistic interpretation of previously published experimental evidence of force occlusion. The models also predict two effects that have not been reported previously - voluntary EMG occlusion and the advantages of a proximal stimulation site. This study provides a basis for the rational design of both future experiments and clinical neuroprosthetic interventions involving either motor or sensory stimulation.
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影响因子：
4
作者：
Crago, Patrick E.;Makowski, Nathaniel S.
通讯作者：
Makowski, Nathaniel S.
影响因子：
3.3
作者：
KNAFLITZ, M;MERLETTI, R;DE LUCA, CJ
通讯作者：
DE LUCA, CJ
影响因子：
3.3
作者：
Perumal, Ramu;Wexler, Anthony S.;Binder-Macleod, Stuart A.
通讯作者：
Binder-Macleod, Stuart A.
影响因子：
2.5
作者：
Herbert, RD;Gandevia, SC
通讯作者：
Gandevia, SC
影响因子：
11
作者：
BORG, J
通讯作者：
BORG, J