VESTIBULOSPINAL CONTROL OF POSTURE AND LOCOMOTION

这项研究的长期目标是了解紧张情绪是如何 系统控制姿态和平衡，特别是 前庭系统在这一控制中起作用。维护的能力 站姿过程中的稳定性是成功表演的基础 许多功能性运动任务，但对其机制知之甚少 CNS用来解决复杂的姿态控制问题。 头晕是临床医生最常见的主诉之一， 头晕的症状通常伴随着平衡方面的问题。 这些不稳定的问题中有很大一部分可能是 前庭的与前庭系统的病理、损伤或退化有关的 因此，重要的是要了解前庭输入是如何被 发动机系统要保持站姿和稳定性。这样做的目的是 建议研究前庭管道和耳石在 通过实验和实验实现对姿态和运动的动态控制 计算建模。实验将量化的动力学 猫前后的自由站姿和跑步机运动 前庭器官的损伤。有两个假设构成了 拟议的工作：i)需要动态稳定头部以 保持与地面垂直的稳定姿势，以及，ii) 前庭输入改变会导致由以下原因引起的宫缩亢进 增加了系统增益。 具体目标是1)对频率响应进行量化 无拘无束平衡控制系统的特点 直立动物，通过对支撑物施加正弦扰动 浮出水面。我们将采用系统分析的方法来分析 猫的每个肢体下的地面反作用力，身体的位置 节段(尤其是头部)、关节扭矩、中心轨迹 以及所选肌肉的肌电活动 脖子、躯干和四肢。2)确定相互之间的协调模式 运动过程中的头部运动和肢体运动，3)量化 低阈值刺激脊髓局部环路的兴奋性 皮肤神经。所有这些程序都将在之前和 前庭器官损伤后(全双侧 迷路切除，或双侧半规管堵塞)。这个 动物模型的优点是能够精确地控制 损伤，并在急性期跟踪每只动物 经历感觉-运动适应。每只动物都将接受所有的测试 行为，并将作为自己的控制。最后，4)创建一个 CAT平衡控制系统的计算模型，包含注释 不仅是本体感受器，还包括基于头部的传感器(前庭、视觉、 和颈部本体感受器)。这些研究产生的数据和模型 将提供对神经运动控制过程的宝贵见解，并将 导致关于前庭功能障碍的新假说和预测 以及在改变的力场环境下的前庭功能。

The long-term goal of this research is to understand how the nervous system controls stance and balance and, in particular, what role the vestibular system plays in this control. The ability to maintain stability during stance is fundamental for the successful performance of many functional motor tasks, and yet little is known about the mechanisms that the CNS uses to solve the complex control problems of stance. Dizziness is one of the most common complaints faced by clinicians, and symptoms of dizziness are often accompanied by problems with balance. A significant proportion of these problems of instability could be related to pathology, injury, or degeneration in the vestibular system. Therefore, it is vital to understand how vestibular inputs are used by the motor system to maintain stance and stability. The goal of this proposal is to examine the role of the vestibular canals and otoliths in the dynamic control of stance and locomotion through experimentation and computational modelling. Experiments will quantify the dynamics of unrestrained stance and treadmill locomotion in cats, before and after lesions of the vestibular apparatus. Two hypotheses underlie the proposed work: i) that dynamic stabilization of the head is required for maintaining a stable postural orientation to earth vertical and, ii) altered vestibular input results in hypermetria that arises from increased system gain. The specific aims are 1) to quantify the frequency response characteristics of the balance control system of the unrestrained standing animal, by applying sinusoidal perturbations to the support surface. A systems analysis approach will be applied in analyzing the ground reaction forces under each limb of the cat, positions of the body segments (especially the head), joint torques, trajectory of the center of mass, and electromyographic activity from selected muscles of the neck, trunk, and limbs. 2) to determine patterns of coordination between head movement and limb movement during locomotion, 3) to quantify the excitability of local spinal circuits using low-threshold stimulation of cutaneous nerves. All these procedures will be carried out before and after lesion of the vestibular apparatus (either total bilateral labyrinthectomy, or bilateral plugging of the semicircular canals). The advantage of the animal model is the ability to precisely control the lesion, and to follow each animal during the acute phase and as it undergoes sensory-motor adaptation. Each animal will be tested in all behaviors and will serve as its own control. Finally, 4) to create a computational model of the cat balance control system, incorporating not only proprioceptors, but also the head-based sensors (vestibular, visual, and neck proprioceptors). The data and models generated by these studies will provide valuable insights into neuromotor control processes and will lead to new hypotheses and predictions about vestibular dysfunction as well as vestibular function under altered force field environments.