Beuter A, Larocque D, Glass L
Département de Kinanthropologie, Université du Québec a Montréal, Canada.
J Mot Behav. 1989 Sep;21(3):277-89. doi: 10.1080/00222895.1989.10735482.
Experiments were performed to investigate the oscillations arising in a human motor system with delayed visual feedback. Eight subjects were instructed to maintain a constant finger position relative to a stationary baseline. The finger displacement was measured using a microdisplacement transducer connected to the index finger, and was displayed on an oscilloscope. Time delays between 40 and 1,500 ms were inserted in the visual feedback loop for 100 s. Results show that, as the time delays increase, irregular rhythms appear with short intermittent periods of regular oscillations. These regular low-frequency oscillations have an amplitude that increases with the time delays and a period that is consistently about 2 to 4 times the time delay. Fast Fourier Transforms (FFT) show a peak between 8 and 12 Hz, corresponding to physiological tremor in half the subjects. No systematic variations in the FFT for the 2 to 15 Hz range were observed as time delay increased. In the 0 to 2 Hz range, the FFT show a consistent increase in power with the time delay. These results indicate that, under the conditions of this experiment, tremor is not affected by time delays in the visuomotor system, and time delays in the visuomotor feedback loop give rise to complex oscillatory behaviors.
进行了实验以研究具有延迟视觉反馈的人体运动系统中出现的振荡。八名受试者被指示相对于固定基线保持手指位置不变。使用连接到食指的微位移传感器测量手指位移，并在示波器上显示。在视觉反馈回路中插入40至1500毫秒的时间延迟，持续100秒。结果表明，随着时间延迟增加，会出现不规则节律，伴有短时间的间歇性规则振荡。这些规则的低频振荡的振幅随时间延迟增加，周期始终约为时间延迟的2至4倍。快速傅里叶变换（FFT）显示在8至12赫兹之间有一个峰值，对应于一半受试者的生理性震颤。随着时间延迟增加，在2至15赫兹范围内未观察到FFT的系统性变化。在0至2赫兹范围内，FFT显示功率随时间延迟持续增加。这些结果表明，在本实验条件下，震颤不受视觉运动系统中时间延迟的影响，视觉运动反馈回路中的时间延迟会产生复杂的振荡行为。
