Doeringer J A, Hogan N
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
J Neurophysiol. 1998 Oct;80(4):1787-99. doi: 10.1152/jn.1998.80.4.1787.
It has been observed for nearly 100 years that visually guided human movements appear to be composed of submovements, intermittently executed overlapping segments. This paper presents experiments to investigate the pervasiveness of movement intermittency and, in particular, whether it is exclusively due to visual feedback. With and without visual feedback, human subjects were asked to 1) move with constant velocity and 2) draw elliptical figures on a phase-plane display (showing velocity vs. position) that required cyclic movements at different frequencies. In both tasks, we found that removal of visual feedback did not significantly change movement intermittency. Subjects were unable to generate movements at constant speed. In addition, subjects moved less smoothly when drawing slower phase-plane ellipses. Furthermore, elliptical phase-plane figures were not always drawn at the frequency suggested by the center of the display. Instead, subjects moved more slowly than the tall (fast) ellipse displays suggested, and faster than the wide (slow) displays suggested. These results show that 1) movement intermittency is not exclusively due to visual feedback and 2) may in fact be a fundamental feature of movement behavior.
近100年来人们观察到，视觉引导的人类动作似乎由子动作组成，即间歇性执行的重叠片段。本文介绍了一些实验，以研究动作间歇性的普遍性，特别是它是否完全归因于视觉反馈。在有和没有视觉反馈的情况下，要求人类受试者：1）以恒定速度移动；2）在相平面显示器（显示速度与位置）上绘制椭圆形，这需要以不同频率进行循环运动。在这两项任务中，我们发现去除视觉反馈并没有显著改变动作间歇性。受试者无法以恒定速度产生动作。此外，受试者在绘制较慢的相平面椭圆时动作不太流畅。此外，椭圆形相平面图形并不总是以显示器中心建议的频率绘制。相反，受试者的移动速度比高（快）椭圆显示器建议的速度慢，比宽（慢）显示器建议的速度快。这些结果表明：1）动作间歇性并非完全归因于视觉反馈；2）实际上可能是动作行为的一个基本特征。
