PHYSIOLOGY & ADAPTIVE CONTROL OF OTOLITH/OCULAR REFLEXES

生理

• 批准号: 6379180
• 负责人: RICHARD A. CLENDANIEL
• 金额: $ 9.99万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6379180
• 关键词: Saimiri; biological signal transduction; eye movements; head movements; human subject; neural information processing; neurophysiology; otocyst /otolith; semicircular duct; vestibuloocular reflex

Vestibulo-ocular reflexes (VORs) are responsible for maintaining stability of images on the retina during head movements. Many of the behavioral features and neurophysiological mechanisms underlying control of angular VORs have been elucidated. Comparatively little is known about the organization of otolith-ocular reflexes Or their adaptive capabilities. Otolith-ocular reflexes generate three types of compensatory eye movements: 1) ocular counterrolling in response to dynamic and static head tilt, 2) linear VORs in response to dynamic linear movements, and 3) nystagmus induced by constant velocity off vertical axis rotation. Vestibular nerve afferents innervating the otoliths cannot distinguish between movements leading to each of these three responses. Research described in this project will define mechanisms involved in the signal processing leading to these three responses. The capabilities and mechanisms involved in the adaptation of the otolith-ocular reflexes will also be studied as an example of motor learning. The long-term goal of this research is-to define the mechanisms involved in the specification and adaptive control of otolith-ocular reflexes, with the practical aim of improving the diagnosis and treatment (rehabilitation) of patients with vestibular disorders. The specific objectives of this proposal are l) to define the physiological properties of central vestibular neurons that receive both semicircular canal and otolith afferents in squirrel monkeys and 2) to define the mechanisms responsible for adaptive control of angular and linear VORs in both squirrel monkeys and humans. Three dimensional and vergence eye movements in both monkeys and humans, as well as single-unit activity in the vestibular nuclei of the squirrel monkeys, will be recorded. Otolith-ocular reflexes will be elicited in response to static and dynamic head tilt, eccentric rotations, and linear translations. The role of angular velocity signals, phasic-tonic responses of irregular otolith afferents, and frequency-specific filtering of otolith signals in these processes will be determined in monkeys through bilateral semicircular canal plugging and functional ablation of the irregular afferents. Adaptation will be elicited using visual-vestibular conflict paradigms. Transfer of adapted VOR gain to reflexes induced by differing combinations of semicircular canal and otolith activity will identify points of convergence in these pathways and define mechanisms involved in the generation of angular velocity signals from otolith activity.

前庭眼反射（VORs）负责维持 头部运动期间视网膜上图像的稳定性。许多 行为特征和神经生理机制 已经阐明了角VOR的控制。相对来说， 关于耳石眼反射的组织或它们的 适应能力。耳石眼反射产生三种类型的 代偿性眼球运动：1）眼球反转， 动态和静态头倾斜，2）响应动态和静态头倾斜的线性VOR 直线运动，3）恒定速度关闭引起的眼球震颤 垂直轴旋转。前庭神经传入支配 耳石无法区分导致这些运动的运动 三个答案。本项目中描述的研究将定义 信号处理中涉及的机制导致了这三个 应答适应所涉及的能力和机制 的耳石眼反射也将研究作为一个例子， 运动学习本研究的长期目标是： 参与规范和自适应控制的机制 耳石-眼反射，其实际目的是改善 前庭神经痛的诊断和治疗（康复） 紊乱本提案的具体目标是：（1）确定 中枢前庭神经元的生理特性 半规管和耳石传入， 2)定义负责自适应控制角度的机制， 和人类的线性VOR。三维 以及人类和猴子的聚散眼球运动， 松鼠猴前庭神经核的单单位活动， 将被记录。耳石眼反射将被引发的反应 静态和动态头部倾斜、偏心旋转和线性 翻译.角速度信号的作用，相位紧张 不规则耳石传入的反应，和频率特异性 这些过程中耳石信号的滤波将在 猴通过双侧半规管堵塞和功能 切除不规则传入神经将通过以下方式引发适应： 视觉-前庭冲突范例。将自适应VOR增益转移到 半规管和神经管的不同组合引起的反射 耳石活动将确定这些途径的汇合点 并定义了角速度产生的机制 耳石活动的信号。