PHYSIOLOGY OF VESTIBULAR COMPENSATION

负责控制前庭过程的中枢通路通常 接收在所述放电中编码的关于头部移动的信息 前庭神经传入神经支配每个迷路的特性。 一侧前庭终末器官的这些输入的改变导致 扭曲的前庭反射和唤起补偿机制。 单侧前庭损伤后的变化及前庭功能的改变 对介导补偿的神经生理学事件知之甚少。 将在警觉松鼠中进行行为和单单位研究 猴子确定角前庭眼补偿机制 反射后，每两个单侧前庭病变。一个病变 范式将涉及三个单方面的机械失活 半规管和其他将包括单边 前庭神经切除术运河堵塞可以保护 前庭神经传入紧张性放电，而前庭神经切除术 前庭神经切除术导致永久性消融所有 损伤侧的前庭传入活动。 这两个前庭病变将用于解决三个具体目标。 I）每个前庭损伤对增益和对称性的行为影响 角水平和垂直前庭眼反射（VORs） 将在受过训练的警觉松鼠猴身上进行研究， 并做出平滑的追踪眼球运动。紧张性前庭的作用 在恢复VOR增益时，通道阻塞后保留的传入活动 并定义对称性。2)中心燃烧特性 将记录分离在前庭核中的前庭神经元， 警觉的、受过训练的松鼠猴， 在每一个前庭损伤后观察到VOR的变化。第三章 前庭中枢神经元对电极化的反应 通过植入的肾上腺素刺激电极输送， 研究了来自非病变迷路的前庭输入在癫痫发作中的作用 两种前庭损伤后的补偿机制将 从而被表征。 这些研究将加深我们对正常前庭神经的理解。 过程，并有助于定义可塑性的过程， 适应这个系统。本提案中描述的研究是 与前庭疾病的诊断和治疗直接相关 在人类身上。

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.