ANGULAR AND LINEAR VESTIBULOCOLLIC REFLEXES IN HUMANS

头部的适当稳定对于人类进行 日常生活中的许多基本活动。在大多数情况下， 我们参与的活动是以刻板印象的姿势进行的 关于地心引力。这有助于保持 头部在空间中的特殊感觉感受器，并调节 头部在躯干上，作为整体姿势控制的一部分。 前庭结肠反射，它利用头部位置的信息 耳石和半规管感受器中的速度传感器 前庭迷路产生颈部肌肉活动以稳定 头部是头部稳定系统的关键部分。 我们的长期目标是确定前庭结肠反射(VCR) 有助于在线性、角度和组合过程中稳定头部 躯干在矢状面和额面处的线角摄动 飞机。本项目集中在由以下方面生成的VCR的作用 耳石传入和它们与更好的相互作用的方式 已知的半规管录像机。我们提出了两个系列的实验 正常的人类志愿者。第一个将考察线性和 角度VCR彼此交互，并产生头部运动 通过自愿性和视觉运动系统。这将有助于我们理解 录像机有助于保持磁头稳定的环境和 它们被马达的其他部分调节或“门控”的方式 控制系统。 第二个系列的实验将测量动态特性 各种频率和类型的耳石和耳道录像机 在使视觉和视觉的贡献最小化的条件下的刺激 自愿头部运动系统。我们将研究这两种反射。 在旋转或平移躯干时，头部是自由的 当录像机在旋转或旋转过程中被隔离研究时移动 头部固定在树干上的平移。这些实验将 帮助我们理解在这些反射中发生的内部处理 以及它们的输出被生物力学改变的方式 头颈系统的特性。 实验结果将使用两个模型进行解释。第一个是 一个从经过充分测试的前庭眼球反射开始的动态模型 对非线性行为和多个旋转轴进行建模并添加 描述头部运动系统的特征。它将包含一些元素 与已知的迷路受体和反射的生理学相对应 并将尝试显示位置、速度和加速度 信息，嵌入在规则和不规则的发射模式中 外周传入，驱动颈部肌肉保持稳定 头飞向太空。第二个是人体的详细生物力学模型。 头颈系统，量化所有关节、肌肉和 被动力学，并允许预测适当的肌肉模式 活动稳定头部，面对棱角分明和线条分明 微扰。

Proper stabilization of the head is essential for humans to carry out many of the essential activities of daily living. Throughout most of the activities in which we engage the head is held in a stereotyped position with respect to gravity. This helps to maintain the orientation of the head's special sensory receptors in space and regulates the attitude of the head on the trunk as part of overall postural control. Vestibulocollic reflexes, which utilize information from head position and velocity sensors in the otolith and semicircular canal receptors of the vestibular labyrinth to generate neck muscle activity to stabilize the head are a critical part of the head stabilization system. Our long-term goal is to determine how vestibulocollic reflexes (VCRs) contribute to head stabilization during linear, angular and combined linear-angular perturbations of the trunk in the sagittal and frontal planes. This project concentrates on the role of VCRs generated by otolith afferents and on the ways in which they interact with better known semicircular canal VCRs. We propose two series of experiments on normal human volunteers. The first will examine how the linear and angular VCRs interact with one another and with head movements generated by voluntary and visuomotor systems. This will help us understand the contexts in which VCRs contribute to maintaining head stability and the ways in which they are regulated or "gated" by other parts of the motor control system. The second series of experiments will measure the dynamic properties of otolith and canal VCRs across a wide range of frequencies and types of stimuli under conditions that minimize the contribution of visual and voluntary head movement systems. The two reflexes will be studied together during rotations or translations of the trunk with the head free to move while the VCRs will be studied in isolation during rotations or translations with the head fixed to the trunk. These experiments will help us understand the internal processing that occurs in these reflexes and the way in which their output is modified by the biomechanical properties of the head-neck system. Experimental results will be interpreted using two models. The first is a dynamic model which starts with well tested vestibuloocular reflex models and adds non-linear behavior and multiple rotation axes that characterize the head movement system. It will incorporate elements corresponding to known physiology of labyrinthine receptors and reflex pathways and will attempt to show how position, velocity and acceleration information, embedded in firing patterns of regular and irregular peripheral afferents, drives neck muscles to maintain stability of the head in space. The second is a detailed biomechanical model of the human head-neck system that quantifies the actions of all joints, muscles and passive mechanics and allows prediction of appropriate patterns of muscle activity to stabilize the head in the face of angular and linear perturbations.