Attenuation of muscle spindle firing with artificially increased series compliance during stretch of relaxed muscle.
Attenuation of muscle spindle firing with artificially increased series compliance during stretch of relaxed muscle.
复制标题
在放松肌肉拉伸过程中，人为增加系列顺应性，从而减弱肌梭放电。
DOI：
10.1113/ep090872
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发表时间：
2024
影响因子：
2.7
通讯作者：
Ting,LenaH
中科院分区：
文献类型：
--
作者：
Abbott,EmilyM;Stephens,JacobD;Simha,SurabhiN;Wood,Leo;Nardelli,Paul;Cope,TimothyC;Sawicki,GregoryS;Ting,LenaH
肌梭为运动和姿势传递重要的机械感觉信息，但肌梭反馈通过顺应性肌腱与骨骼运动耦合。关于运动过程中肌腱顺应性对肌梭反馈的影响知之甚少，而肌梭的复杂放电使得这些影响难以预测。我们的目标是研究肌梭发射的变化，使用添加的系列弹性元件（SEES），以模仿一个更顺应性的肌腱，并表征伴随的变化，在发射相对于肌肉肌腱单位（MTU）和肌束位移（通过sonomicrometry记录）。分析正弦、斜坡-保持和三角形拉伸，以检查运动和扰动样拉伸中肌梭瞬时放电率（IFR）的潜在变化以及序列历史依赖性。添加的SEE有效降低了整体MTU刚度，并普遍降低了肌梭放电率，但不同拉伸类型的效果不同。在正弦拉伸过程中，峰值和平均放电率没有降低，IFR与肌束速度的相关性最好。在斜坡拉伸，SEE减少了初始突发，动态和静态响应的主轴。值得注意的是，IFR呈负相关，在保持阶段的肌束位移。在三角形拉伸，SEES减少了平均IFR在第一和第二拉伸，影响了序列的历史依赖平均IFR。总的来说，这些结果表明，肌腱顺应性可能会减弱运动过程中的肌梭反馈，但这些变化不能完全解释为减少肌束长度或速度，或MTU力。
Muscle spindles relay vital mechanosensory information for movement and posture, but muscle spindle feedback is coupled to skeletal motion by a compliant tendon. Little is known about the effects of tendon compliance on muscle spindle feedback during movement, and the complex firing of muscle spindles makes these effects difficult to predict. Our goal was to investigate changes in muscle spindle firing using added series elastic elements (SEEs) to mimic a more compliant tendon, and to characterize the accompanying changes in firing with respect to muscle–tendon unit (MTU) and muscle fascicle displacements (recorded via sonomicrometry). Sinusoidal, ramp‐and‐hold and triangular stretches were analysed to examine potential changes in muscle spindle instantaneous firing rates (IFRs) in locomotor‐ and perturbation‐like stretches as well as serial history dependence. Added SEEs effectively reduced overall MTU stiffness and generally reduced muscle spindle firing rates, but the effect differed across stretch types. During sinusoidal stretches, peak and mean firing rates were not reduced and IFR was best‐correlated with fascicle velocity. During ramp stretches, SEEs reduced the initial burst, dynamic and static responses of the spindle. Notably, IFR was negatively related to fascicle displacement during the hold phase. During triangular stretches, SEEs reduced the mean IFR during the first and second stretches, affecting the serial history dependence of mean IFR. Overall, these results demonstrate that tendon compliance may attenuate muscle spindle feedback during movement, but these changes cannot be fully explained by reduced muscle fascicle length or velocity, or MTU force.