Characterization of the disruption of neural control strategies for dynamic fingertip forces from attractor reconstruction.
Characterization of the disruption of neural control strategies for dynamic fingertip forces from attractor reconstruction.
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DOI：
10.1371/journal.pone.0172025
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
Valero-Cuevas FJ
中科院分区：
文献类型：
--
作者：
Peppoloni L;Lawrence EL;Ruffaldi E;Valero-Cuevas FJ
强度-灵活性（SD）测试测量拇指和食指的指腹压缩在低力（<3 N）下易于弯曲的顺应性和细长弹簧的能力。我们知道，诸如衰老和神经退行性疾病等因素会带来恶化的生理变化（例如，在运动皮层、小脑和基底神经节水平），这导致灵巧能力的整体丧失。然而，人们对这些变化如何反映潜在生物系统的动态知之甚少。弹簧手系统具有非线性动力学行为，在这里，我们描述的动力学行为的相图使用吸引子重建。30名参与者进行了SD测试：10名年轻人，10名老年人和10名帕金森病（PD）老年人。我们使用延迟嵌入的作用力来重建其吸引子。我们的特点是分布的点的相图，其密度（远点和四分位数范围）和几何特征（轨迹长度和大小）。我们发现老年人的相位图比年轻人显示出更远的点（p = 0.028），PD参与者的四分位数范围（p = 0.001），轨迹长度（p = 0.005）和大小（p = 0.003）比他们的健康同行更大。随着健康老龄化，相图的尺寸增加表明系统的动态特性发生了变化，这可能代表神经控制策略的减弱。相比之下，PD中吸引子的扭曲表明潜在生物系统的根本变化，以及神经控制策略的中断。这种检测健康和病理衰老中灵巧性生物机制差异的能力提供了一种简单的方法来评估它们在神经退行性疾病中的破坏，并证明了进一步研究以了解与生理变化的联系。
The Strength-Dexterity (SD) test measures the ability of the pulps of the thumb and index finger to compress a compliant and slender spring prone to buckling at low forces (<3N). We know that factors such as aging and neurodegenerative conditions bring deteriorating physiological changes (e.g., at the level of motor cortex, cerebellum, and basal ganglia), which lead to an overall loss of dexterous ability. However, little is known about how these changes reflect upon the dynamics of the underlying biological system. The spring-hand system exhibits nonlinear dynamical behavior and here we characterize the dynamical behavior of the phase portraits using attractor reconstruction. Thirty participants performed the SD test: 10 young adults, 10 older adults, and 10 older adults with Parkinson’s disease (PD). We used delayed embedding of the applied force to reconstruct its attractor. We characterized the distribution of points of the phase portraits by their density (number of distant points and interquartile range) and geometric features (trajectory length and size). We find phase portraits from older adults exhibit more distant points (p = 0.028) than young adults and participants with PD have larger interquartile ranges (p = 0.001), trajectory lengths (p = 0.005), and size (p = 0.003) than their healthy counterparts. The increased size of the phase portraits with healthy aging suggests a change in the dynamical properties of the system, which may represent a weakening of the neural control strategy. In contrast, the distortion of the attractor in PD suggests a fundamental change in the underlying biological system, and disruption of the neural control strategy. This ability to detect differences in the biological mechanisms of dexterity in healthy and pathological aging provides a simple means to assess their disruption in neurodegenerative conditions and justifies further studies to understand the link with the physiological changes.