Multi-joint coordination in upright stance: The uncontrolled manifold helps decouple control of body-in-space from control of other degrees of freedom

仅根据质心在空间中的位置进行分析。倒立摆假说证明了这一点，根据倒立摆假说，通过控制脚踝关节来实现直立姿势。然而，最近的经验表明，倒立摆假说并不是一个很好的近似。其他关节比踝关节更易变，关节方差是一种反映姿势任务的方式：离开质量进入不变的子空间比影响质心的子空间发生更多的方差。该建议旨在基于无控制流形假设为直立姿势的控制建立一个新的理论解释，根据该假设，所有关节的神经元控制信号以特定于任务的方式耦合。我们将扩展一个非受控流形的神经元动力学模型，包括引力，并解释如何将空间中物体的运动状态的估计反馈到运动链上的所有肌肉关节系统。我们将通过与已发表的实验数据以及约翰·肖尔茨教授实验室获得的新数据的详细比较来验证该模型。如果成功，理论工作将结合建模和对实验数据的分析，建立一个新的概念，即直立姿势下的估计问题如何与控制问题联系起来。

analyzed only in terms of the position of the center of mass in space. This is justified by the inverted pendulum hypothesis according to which upright stance is achieved through control of the ankle joint.Recent empirical work has revealed, however, that the inverted pendulum hypothesis is not a good approximation. Other joints are more variable than the ankle joint and joint variance is structured is a way that reflects the postural task: more variance occurs in the subspace that leaves the enter of mass invariant than in the subspace that affects the center of mass.This proposal is aimed to establish a new theoretical account for the control of upright posture based on the uncontrolled manifold hypothesis, according to which the neuronal control signals to all joints are coupled in a task-specific manner. We will extend a neuronal dynamics model of the uncontrolled manifold by including gravitational forces and an account for how the estimation of the kinematic state of the body in space is fed back to all muscle-joint systems along the kinematic chain.We will validate the model by detailed comparison with published experimental data as well as new data obtained in the laboratory of Prof. John Scholz, with whom we will closely collaborate.If successful, the theoretical work, combining modeling with analysis of experimental data, will establish a new conception of how the estimation problem in upright stance is linked to the control problem.