Direction-Dependent Control of Balance During Walking and Standing
Direction-Dependent Control of Balance During Walking and Standing
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DOI：
10.1152/jn.00131.2009
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发表时间：
2009-09-01
影响因子：
2.5
通讯作者：
Kuo, Arthur D.
中科院分区：
文献类型：
--
作者：
O'Connor, Shawn M.;Kuo, Arthur D.
奥康纳SM，郭AD.行走和站立时的方向依赖性平衡控制。神经生理学杂志102：1411-1419，2009年。首次发表于2009年6月24日; doi：10.1152/jn.00131.2009。人类行走以前被描述为“受控的坠落”。“然而，一些计算模型表明，步态也可能具有自我稳定的方面，几乎不需要中枢神经系统控制。行走的前后部分甚至可以从一步到另一步被动地稳定，而横向运动可能是不稳定的，并且需要运动控制来平衡，如通过主动的脚放置。如果是这样的话，行走的人类可能更少地依赖于前后（AP）的综合感觉反馈，而不是中间（ML）的平衡。我们测试了健康人（n = 10）是否表现出这种方向依赖性控制，通过施加低频扰动的视野（投影虚拟走廊）和测量脚的位置在跑步机行走。我们发现步的变异性是近10倍更敏感ML比AP扰动，量化的增加，均方根步的变异性每单位的扰动幅度的变化。这不仅仅是由于AP方向上视觉的生理敏感性较差：应用于安静站立的类似扰动产生了相反的方向依赖性，AP敏感性比ML高2.3倍。串联（脚跟到脚趾）站立产生ML的敏感性比AP的三倍，这表明支持的基础影响站立的稳定性。然而，姿势平衡似乎需要持续的、整合的运动控制来实现各个方向的平衡。相比之下，步行平衡需要逐步的、综合的平衡控制，但主要是在横向方向上。在前后方向上，可以通过“不受控制的”但被动稳定的一系列福尔斯来保持平衡。
O'Connor SM, Kuo AD. Direction-dependent control of balance during walking and standing. J Neurophysiol 102: 1411-1419, 2009. First published June 24, 2009; doi:10.1152/jn.00131.2009. Human walking has previously been described as "controlled falling." Some computational models, however, suggest that gait may also have self-stabilizing aspects requiring little CNS control. The fore-aft component of walking may even be passively stable from step to step, whereas lateral motion may be unstable and require motor control for balance, as through active foot placement. If this is the case, walking humans might rely less on integrative sensory feedback, such as vision, for anteroposterior (AP) than for mediolateral (ML) balance. We tested whether healthy humans (n = 10) exhibit such direction-dependent control, by applying low-frequency perturbations to the visual field (a projected virtual hallway) and measuring foot placement during treadmill walking. We found step variability to be nearly 10 times more sensitive to ML than to AP perturbations, as quantified by the increase in root-mean-square step variability per unit change in perturbation amplitude. This is not simply due to poorer physiological sensitivity of vision in the AP direction: similar perturbations applied to quiet standing produced reversed direction dependence, with an AP sensitivity 2.3-fold greater than that of ML. Tandem (heel-to-toe) standing yielded ML sensitivity threefold greater than that of AP, suggesting that the base of support influences the stability of standing. Postural balance nevertheless appears to require continuous, integrative motor control for balance in all directions. In contrast, walking balance requires step-by-step, integrative control for balance, but mainly in the lateral direction. In the fore-aft direction, balance may be maintained through an "uncontrolled," yet passively stabilized, series of falls.