Plasticity of human motoneurone properties

人类运动神经元特性的可塑性

• 批准号: 105424-2006
• 负责人: Garland, Jayne
• 金额: $ 1.86万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=363304
• 关键词: Plasticity; human; motoneurone; properties

Motor control research using animal models has helped establish relations between properties of the motoneurone and the muscle fibers that it innervates.  In humans, Matthews (1996) developed a model for estimating one of the motoneurone properties (afterhyperpolarization (AHP) time-course).  This model represents one of the only windows to view the properties of motoneurones in humans.  The time-course of the AHP influences the capacity of the motoneurone to discharge action potentials and, thereby, the force produced by the muscle.  The adaptability of the AHP has not been thoroughly investigated in animal models and is virtually unexplored in humans.  The proposed research will determine the capacity of synaptic input to modify the time-course of the motoneurone AHP in humans.  We will study three synaptic inputs in separate experiments: cutaneous (skin) input, muscle spindle input, and input from group III-IV afferents activated by muscle fatigue.  Low-force contractions with the ankle dorsiflexor muscles (tibialis anterior) will be held for 30 min: 10 min before, during, and after the addition of synaptic input, with the motoneurone AHP being calculated in each phase from a train of motor unit potentials collected with a fine wire electrode.  Either a non- painful cutaneous stimulus will be applied to the skin overlying tibialis anterior, or vibration will be applied to the tibialis anterior tendon, or the muscle will be fatigued by performing a low-force contraction under ischemic conditions.  Healthy adult volunteers and volunteers with unilateral motor paresis after stroke will participate in the study.  This research program will advance our understanding of human motoneurone properties when they are activated voluntarily with both descending commands and sensory inputs.  This research will have far-reaching implications for motor control mechanisms that have not been investigated to date, primarily because the corresponding animal experiments do not involve voluntary contractions.  The acquired knowledge will contribute to our understanding of motor control disorders and whether sensory inputs may be useful in modifying motoneurone properties after a neurological insult, such as a stroke.

使用动物模型的运动控制研究有助于建立运动神经元的特性与它所支配的肌肉纤维之间的关系。在人类中，Matthews（1996）开发了一种用于估计一种运动神经元特性（After Empherperpolization（AHP）时间）的模型。该模型代表着查看人类运动神经元属性的唯一窗口之一。 AHP的时间顺序会影响运动神经元发射动作电位的能力，从而影响肌肉产生的力。 AHP的适应性尚未在动物模型中进行彻底研究，在人类中几乎是出乎意料的。拟议的研究将确定突触输入修改人类运动神经元AHP的时间顺序的能力。我们将在单独的实验中研究三个合成输入：皮肤（皮肤）输入，肌肉纺锤体输入以及由肌肉疲劳激活的IIII-IV组的输入。与脚踝背屈肌肉（胫骨前）的低力收缩将在加入突触输入前，和之后和之后保持30分钟：10分钟，并在每个阶段中从每阶段中计算出用细线电极收集的运动单元电位的运动神经元AHP。非疼痛的皮肤刺激将被施加在胫骨前部的皮肤上，或者将振动施加到胫骨前肌腱上，或者通过在缺血性条件下进行低力的肌肉来疲劳。中风后健康的成年志愿者和具有单侧运动的志愿者将参加这项研究。该研究计划将通过下降命令和感觉输入自愿激活人类运动神经元的特性。这项研究将对迄今尚未研究的运动控制机制具有深远的影响，因为相应的动物实验不涉及自愿收缩。获得的知识将有助于我们对运动控制障碍的理解，以及感觉输入是否可能有助于在神经损伤（例如中风）后修改运动神经元特性。