Whole limb kinematics are preferentially conserved over individual joint kinematics after peripheral nerve injury
Whole limb kinematics are preferentially conserved over individual joint kinematics after peripheral nerve injury
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DOI：
10.1242/jeb.033886
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发表时间：
2009-11-01
影响因子：
2.8
通讯作者：
Nichols, T. Richard
中科院分区：
文献类型：
--
作者：
Chang, Young-Hui;Auyang, Arick G.;Nichols, T. Richard
生物力学和神经生理学研究表明，全肢功能是一个重要的运动控制参数。倒立摆和质量弹簧模型大大降低了腿的复杂性，并预测了运动动力学，但没有解决如何协调众多的肢体元素来实现如此简单的行为。作为第一步，我们假设在神经肌肉损伤后，整个肢体的运动学是最重要的，并且比单个关节的运动学更优先保守。我们采用建立良好的猫踝关节伸肌周围神经损伤模型，建立了两个实验损伤组，均具有可预测的暂时性瘫痪和肌肉完全自我神经再生的时间过程。个体关节运动学的平均轨迹由于损伤后的缺陷而改变。相比之下，所有动物的肢体方向和肢体长度的平均轨迹基本保持不变，即使是踝关节伸肌瘫痪，这表明平均关节角度的变化是协调的，作为长期补偿策略的一部分，以尽量减少整个肢体运动学的变化。此外，在每个测量阶段（损伤前、瘫痪和自我再神经支配），个体关节运动学的逐步变化总是显著大于肢体方向的变化。我们的研究结果表明，关节角度组合是协调和选择的，以稳定整个肢体的运动学，防止短期的自然逐步偏差以及长期的损伤造成的病理偏差。这可能代表了一种基本的补偿原则，允许动物在对整体运动功能影响最小的情况下适应不断变化的条件。
Biomechanics and neurophysiology studies suggest whole limb function to be an important locomotor control parameter. Inverted pendulum and mass-spring models greatly reduce the complexity of the legs and predict the dynamics of locomotion, but do not address how numerous limb elements are coordinated to achieve such simple behavior. As a first step, we hypothesized whole limb kinematics were of primary importance and would be preferentially conserved over individual joint kinematics after neuromuscular injury. We used a well-established peripheral nerve injury model of cat ankle extensor muscles to generate two experimental injury groups with a predictable time course of temporary paralysis followed by complete muscle self-reinnervation. Mean trajectories of individual joint kinematics were altered as a result of deficits after injury. By contrast, mean trajectories of limb orientation and limb length remained largely invariant across all animals, even with paralyzed ankle extensor muscles, suggesting changes in mean joint angles were coordinated as part of a long-term compensation strategy to minimize change in whole limb kinematics. Furthermore, at each measurement stage (pre-injury, paralytic and self-reinnervated) step-by-step variance of individual joint kinematics was always significantly greater than that of limb orientation. Our results suggest joint angle combinations are coordinated and selected to stabilize whole limb kinematics against short-term natural step-by-step deviations as well as long-term, pathological deviations created by injury. This may represent a fundamental compensation principle allowing animals to adapt to changing conditions with minimal effect on overall locomotor function.