PHYSIOLOGY OF VESTIBULAR COMPENSATION

前庭代偿的生理学

• 批准号: 2770221
• 负责人: Lloyd Brooks Minor
• 金额: $ 25.74万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-01 至 2000-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2770221
• 关键词: Saimiri; afferent nerve; electrostimulus; labyrinth; labyrinthectomy; neurophysiology; smooth pursuit eye movement; vestibular nerve; vestibuloocular reflex; visual fixation

Central pathways responsible for control of vestibular processes normally receive information about head movements encoded in the discharge properties of vestibular-nerve afferents innervating each labyrinth. Alteration of these inputs from vestibular end-organs on one side results in distorted vestibular reflexes and evokes mechanisms of compensation. The changes following unilateral vestibular lesions and the neurophysiological events mediating compensation are poorly understood. Behavioral and single-unit studies will be performed in alert squirrel monkeys to define mechanisms of compensation in angular vestibulo-ocular reflexes after each of two unilateral vestibular lesions. One lesion paradigm will involve unilateral mechanical inactivation of the three semicircular canals and the other will consist of unilateral labyrinthectomy with vestibular neurectomy. Canal plugging preserves the tonic discharge of vestibular-nerve afferents whereas labyrinthectomy with vestibular neurectomy results in a permanent ablation of all vestibular afferent activity on the lesioned side. These two vestibular lesions will be used to address three specific aims. I) The behavioral effects of each vestibular lesion on gain and symmetry of the angular horizontal and vertical vestibulo-ocular reflexes (VORs) will be studied in alert squirrel monkeys trained to fixate target lights and make smooth pursuit eye movements. The role of tonic vestibular afferent activity preserved after canal plugging in recovery of VOR gain and symmetry will be defined. 2) The firing characteristics of central vestibular neurons isolated in the vestibular nuclei will be recorded in alert, trained squirrel monkeys to determine the neurophysiological basis of changes observed in the VORs after each of the vestibular lesions. 3) The responses of central vestibular neurons to galvanic polarizations delivered through implanted labyrinthine stimulating electrodes will be studied. The role of vestibular inputs from the nonlesioned labyrinth in mechanisms of compensation after each of the two vestibular lesions will thereby be characterized. These studies will enhance our understanding of normal vestibular processes and contribute to defining processes of plasticity and adaptation in this system. Research described in this proposal is directly relevant to the diagnosis and treatment of vestibular disorders in humans.

通常负责控制前庭过程的中心途径 接收有关排放中编码的头部移动的信息 支配每个迷宫的前庭神经传入的特性。 从一侧的前庭端孔中改变这些输入的结果 在扭曲的前庭反射和唤起补偿机制中。 单侧前庭病变和 介导补偿的神经生理事件尚不清楚。 行为和单单元研究将在警报松鼠中进行 猴子定义角度前庭的补偿机制 两个单侧前庭病变中的每一个。一个病变 范式将涉及三个的单方面机械失活 半圆形的运河，另一条将由单方面组成 迷宫切除术和前庭神经切除术。运河插头保存 前庭神经传入的补品排放，而迷宫切除术 前庭神经切除术会导致所有人的永久消融 病变侧的前庭传入活动。 这两个前庭病变将用于解决三个特定目标。 i）每个前庭病变对增益和对称性的行为影响 角度水平和垂直前庭反射（VORS） 将在警报的松鼠猴子中进行研究，以固定目标灯 并进行平稳的追捕眼动。补品前庭的角色 运河插入VOR增益的恢复后，保留了传入活动 和对称性将定义。 2）中央的射击特征 在前庭核中分离的前庭神经元将记录在 警报，训练有素的松鼠猴子确定神经生理基础 每个前庭病变后在VOR中观察到的变化。 3） 中央前庭神经元对电流极化的反应 通过植入的迷宫刺激电极传递将是 研究。来自非属性迷宫中前庭输入的作用 两个前庭病变中的每一个后，补偿机制将 因此具有特征。 这些研究将增强我们对正常前庭的理解 过程并有助于定义可塑性过程和 适应该系统。该提议中描述的研究是 与前庭疾病的诊断和治疗直接相关 在人类中。