Influence of environmental stability on the regulation of end-point impedance during the maintenance of arm posture
Influence of environmental stability on the regulation of end-point impedance during the maintenance of arm posture
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DOI：
10.1152/jn.00135.2012
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发表时间：
2013-02-01
影响因子：
2.5
通讯作者：
Perreault, Eric J.
中科院分区：
文献类型：
--
作者：
Krutky, Matthew A.;Trumbower, Randy D.;Perreault, Eric J.
刘建军，刘建军，刘建军。环境稳定性对手臂姿势维持过程中端点阻抗调节的影响。中国生物医学工程学报（英文版），2009,31(4):444 - 444。2012年12月5日首次发表；doi: 10.1152 / jn.00135.2012。-许多常见的任务会损害手臂沿特定方向的稳定性。只有当手臂的阻抗足以补偿任务的不稳定效应时，才能完成这样的任务。在运动过程中，已经证明可以优先增加最大手臂刚度的方向，即阻抗的静态分量，以补偿方向不稳定的环境。相比之下，许多研究表明，这种控制在姿势任务中是不可能的。尚不清楚这些发现是否代表姿势和运动期间手臂力学控制的根本差异，还是运动研究中使用的对不稳定环境的非自愿反应，但尚未在姿势维持期间进行测试。我们的目标是量化手臂阻抗是如何适应姿势任务，损害稳定性沿特定方向。我们的研究结果表明，阻抗可以通过调节来补偿这些不稳定性，但相对于之前报道的到达过程中的变化来说，这种变化是适度的。我们观察到的变化主要是在端点刚度的大小上，但这些不足以改变最大刚度的方向。此外，端点粘度或惯性的大小没有实质性变化，这表明臂阻抗的主要变化是刚度的选择性增加，以补偿环境的不稳定刚度特性。我们认为，这些适度的变化提供了对不稳定环境的初始非自愿反应，然后才能通过自愿干预影响更大的变化。
Krutky MA, Trumbower RD, Perreault EJ. Influence of environmental stability on the regulation of end-point impedance during the maintenance of arm posture. J Neurophysiol 109: 1045-1054, 2013. First published December 5, 2012; doi:10.1152/jn.00135.2012.-Many common tasks compromise arm stability along specific directions. Such tasks can be completed only if the impedance of the arm is sufficient to compensate for the destabilizing effects of the task. During movement, it has been demonstrated that the direction of maximal arm stiffness, the static component of impedance, can be preferentially increased to compensate for directionally unstable environments. In contrast, numerous studies have shown that such control is not possible during postural tasks. It remains unknown if these findings represent a fundamental difference in the control of arm mechanics during posture and movement or an involuntary response to the destabilizing environments used in the movement studies but not yet tested during posture maintenance. Our goal was to quantify how arm impedance is adapted during postural tasks that compromise stability along specific directions. Our results demonstrate that impedance can be modulated to compensate for these instabilities during postural tasks but that the changes are modest relative to those previously reported during reaching. Our observed changes were primarily in the magnitude of end-point stiffness, but these were not sufficient to alter the direction of maximal stiffness. Furthermore, there were no substantial changes in the magnitude of end-point viscosity or inertia, suggesting that the primary change to arm impedance was a selective increase in stiffness to compensate for the destabilizing stiffness properties of the environment. We suggest that these modest changes provide an initial involuntary response to destabilizing environments prior to the larger changes that can be affected through voluntary interventions.