Multi-level Dynamics of Action-Perception Patterns During Quiet Standing and Locomotion

人体姿势控制系统有两个主要功能：保持稳定的直立姿势，固定身体各部分的方向和位置，作为感知和行动的参考框架。本研究解决的问题是如何整合各种信息源形成姿态目标，这些目标如何在扰动下稳定下来，以及当信息或任务发生变化时，目标如何灵活地重组。本研究特别关注视觉对站立和运动时姿势稳定性的影响。在实验研究中，人类参与者将观看计算机生成的视觉显示，同时监测他们的姿势反应。显示器模拟简单的场景，如隧道或走廊。这些场景是通过头戴式显示器显示的，姿势反应是通过一个系统来测量的，该系统可以检测参与者身体部位的红外标记的位置。本研究的动机是将姿势控制系统概念化为一个两级动力系统。低级动力学实现了姿势稳定性和恒定的运动速度。高级动力学通过调整低级动力学的参数以适应环境约束来实现灵活性。这种关卡间的划分通过拼凑简单的控制策略来实现灵活性。本研究的一个新贡献是提出了关于高级控制器如何影响低级控制器的具体建议。这些研究的结果将增加我们对人类姿势控制的理解，也可能为治疗姿势控制障碍（例如，老年人跌倒）指明道路。

The human postural control system serves two main functions: to maintain a stable upright posture, and to fix the orientation and position of the body segments that serve as a reference frame for perception and action. The question this research addresses is how various sources of information are integrated to form postural goals, how these goals are stabilized against perturbations, and how the goals are flexibly reorganized when the information or tasks change. In particular, the proposed research focuses on the contribution of vision to postural stability during standing and locomotion. In the experimental studies human participants will view computer-generated visual displays while their postural responses are monitored. The displays simulate simple scenes, such as a tunnel or hallway. The scenes are shown through a head-mounted display and postural responses are measured with a system that detects the position of infra-red markers on body segments of the participant. The research is motivated by a conceptualization of the postural control system as a two-level dynamical system. The low-level dynamics achieves postural stability and constant velocity of locomotion. The high-level dynamics achieves flexibility by tuning the parameters of the low-level dynamics to environmental constraints. This division between levels achieves flexibility by piecing together simple control strategies. A new contribution of this research is a concrete proposal as to how the high-level controller influences the low-level controller. The results of the studies will add to our understanding of human postural control, and may also point the way toward remedies for impairments of postural control (e.g., falling in the elderly).