Coordination Dynamics

许多常见的行为需要有节奏地协调四肢。这些动作的范围从行走中相对简单的双腿协调到杂耍中非常复杂的双手协调。这些协调行为需要身体的许多自由度——也就是说，它的四肢、关节、肌肉，甚至运动神经元——以某种方式被利用起来，作为一个单元来完成一项特定的任务。然而，这种组织显示出一种相当特殊的灵活性：尽管稳定，但它也必须是暂时的，以便这些相同的自由度可以重新组织，不仅是为了完成一些其他特定的任务（玩杂耍的手也是鼓掌的手），而且还允许系统对扰动做出反应（在不平坦的人行道上绊倒）。提出的研究的首要目标是确定控制这些有节奏的组织或协同作用的形成、稳定性和可变性的物理原理。在过去的十年中，我们的研究促进了对运动协调的理解，运动协调是有用的，也是最合适的，作为一个特殊的物理方法，即自组织系统的问题来解决。拟议的研究将使用几类实验来探索这样一种观点，即普通心理现象的物理基础，如学习、记忆、遗忘、注意力和适应，可以用运动协调作为试验场来检验。基本方法包括要求参与者有节奏地摆动手持钟摆，保持直立姿势，或表演瀑布杂耍。操纵（例如，参与者的专业知识或惯用手；钟摆的长度和质量、振荡频率或相位；强加的无关任务；视觉结构的可用性或连续性）是由对物理视角的某些期望所激发的。三维运动分析仪和力平台将用于收集数据。我们追求的理念是，控制运动协调的原则是自组织物理系统的原则，这些原则的发现和表达将受益于非线性动力学的工具。理解控制运动协调的物理原理应该为节奏和姿势障碍的新假设提供来源，并为协调及其获得如何建模提供约束。

Many common behaviors require coordinating two limbs rhythmically. These range from the relatively simple coordination of two legs in walking to the very complex coordination of two hands in juggling. These acts of coordination require that the body's very many degrees of freedom--that is, its limbs, joints, muscles, even motor neurons--somehow get harnessed to function as units to accomplish a specific task. This organization displays a rather special flexibility, however: Although stable, it must also be temporary so that those same degrees of freedom can be reorganized, not only in order to accomplish some other specific task (the hands that juggle are also the hands that applaud) but also to allow the system to respond to perturbations (tripping on an uneven sidewalk). The overarching goal of the proposed research is to identify the physical principles that govern the formation, stability, and variability of these kinds of rhythmic organizations or synergies. Over the past decade, our research has contributed to the understanding that movement coordination is usefully and most appropriately addressed as a problem in a particular approach to physics, that of self-organizing systems. The proposed research will use several classes of experiments to explore the idea that the physical basis of common psychological phenomena such as learning, retention, forgetting, attention, and adaptation can be examined using movement coordination as a testing ground. Basic methodologies include requiring participants to swing hand-held pendulums rhythmically, to maintain an upright posture, or to perform cascade juggling. Manipulations (e.g., of participant expertise or handedness; of pendulum lengths and masses, oscillation frequency or phase; the imposition of extraneous tasks; the availability or continuity of visual structure) are motivated by certain expectations of the physical perspective. Three-space motion analyzers and force platforms will be used to collect the data. We pursue the idea that the principles governing movement's coordination are the principles of self-organizing physical systems and that the discovery and expression of these principles will benefit from the tools of nonlinear dynamics. Understanding the physical principles that govern movement's coordination should provide a source of new hypotheses about rhythmic and postural disorders as well as providing constraints on how coordination and its acquisition might be modeled.