OTOLITH OCULAR REFLEXES--PHYSIOLOGY AND ADAPTIVE CONTROL

耳石眼反射——生理学和适应性控制

• 批准号: 6201698
• 负责人: Lloyd Brooks Minor
• 金额: $ 10.15万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2001-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6201698
• 关键词: Saimiri; antidromic impulse; auditory reflex; electrodes; eye movements; head movements; neurons; nystagmus; otocyst /otolith; posture; single cell analysis

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. These reflexes can be divided into three categories according to the type of compensatory eye movements arising from their activation. Ocular counterrolling is the otolith-ocular reflex that causes torsional movement of the eyes around a line of sight in response to dynamic and static lateral head tilt. Translational linear VORs are eye movements that occur in response to dynamic linear movements of the head. The nystagmus induced by constant velocity rotation about an off-vertical axis results from an angular velocity signal generated by central processing of otolith activity. 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 specification and adaptive control of otolith-ocular reflexes. Three dimensional and vergence eye movements as well as single-unit activity in the vestibular nuclei will be recorded in alert squirrel monkeys before and after bilateral inactivation of all semicircular canals with a plugging procedure. Hypotheses related to processes that distinguish tilt from translational responses will be tested. The role of angular velocity signals, phasic-tonic responses of irregularly discharging otolith afferents, and frequency-specific filtering of otolith signals in these processes will be determined. The physiological properties of neurons in the vestibular nuclei involved in otolith-ocular control will be defined. Profiles of otolith and semicircular canal afferent inputs to these neurons will be identified in relation to translational and tilt stimuli. Studies of adaptation introduced by optokinetic stimuli in association with motions producing specific profiles of otolith and semicircular canal activation will provide further information about signals used to distinguish these responses. 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 generation of angular velocity signals from otolith activity. This research will enhance our understanding of otolith-ocular responses and the processes involved in short-term VOR adaptation. The studies are directly relevant to the diagnosis and treatment of dysfunction in human otolith-ocular reflexes.

前庭 - 眼反射（VOR）负责保持稳定性 在头部移动期间，视网膜上的图像。许多行为 角度控制的特征和神经生理机制 VOR已被阐明。关于 耳石 - 眼反射的组织。 这些反射可以分开 根据补偿性眼动的类型分为三类 由于它们的激活而产生。眼反面是耳石 - 反射会导致眼睛围绕视线的扭转运动 响应动态和静态的侧向倾斜。翻译线性 VOR是响应动态线性运动而发生的眼睛运动 头。通过恒定速度旋转引起的眼球震颤 垂直轴是由由角速度信号产生的 耳石活性的中央处理。前庭神经传入 支配耳石无法区分导致的运动 这三个回应中的每一个。该项目中描述的研究将 定义涉及规范和自适应控制的机制 耳石 - 眼反射。 三维和狂热的眼动以及单单元 前庭核中的活性将记录在警报的松鼠中 猴子在所有半圆形管的双侧灭活之前和之后 使用插头。与过程有关的假设 将测试倾斜度与翻译反应的区分。的作用 角速度信号，不规则的阶段性响应 排放耳石传入和耳石的频率特异性过滤 这些过程中的信号将被确定。生理 前庭核中神经元的性质 控制将被定义。耳石和半圆形管的轮廓 这些神经元的传入输入将与 翻译和倾斜刺激。提出的适应研究 光动力学刺激与产生特定运动的动作相关 耳石和半圆形管激活的轮廓将进一步提供 有关用于区分这些响应的信号的信息。转移 改编的VOR增益是由不同的组合引起的反射 半圆形管和耳石活动将确定 这些途径中的收敛并定义了与生成有关的机制 耳鼻喉活性的角速度信号。 这项研究将增强我们对耳石 - 眼反应的理解 以及涉及短期VOR适应的过程。研究是 与人类功能障碍的诊断和治疗直接相关 耳石 - 眼反射。