W. M. Keck Science Center, The Claremont Colleges, Claremont, California 91711, USA.
Department of Applied Mechanics, Budapest University of Technology and Economics and MTA-BME Lendület Human Balancing Research Group, 1111 Budapest, Hungary.
Phys Rev E. 2018 Aug;98(2-1):022223. doi: 10.1103/PhysRevE.98.022223.
Models for the stabilization of an inverted pendulum figure prominently in studies of human balance control. Surprisingly, fluctuations in measures related to the vertical displacement angle for quietly standing adults with eyes closed exhibit chaos. Here we show that small-amplitude chaotic fluctuations ("microchaos") can be generated by the interplay between three essential components of human neural balance control, namely time-delayed feedback, a sensory dead zone, and frequency-dependent encoding of force. When the sampling frequency of the force encoding is decreased, the sensitivity of the balance control to changes in the initial conditions increases. The sampled, time-delayed nature of the balance control may provide insights into why falls are more common in the very young and the elderly.
倒立摆模型在人体平衡控制研究中占有重要地位。令人惊讶的是，闭眼安静站立的成年人与垂直位移角度相关的测量值出现混沌波动。在这里，我们表明小幅度混沌波动（“微混沌”）可以通过人体神经平衡控制的三个基本组成部分的相互作用产生，即时滞反馈、感觉盲区和力的频率相关编码。当力编码的采样频率降低时，平衡控制对初始条件变化的敏感性增加。平衡控制的采样、时滞性质可能提供一些线索，说明为什么在非常年幼和年长的人更容易摔倒。
