OTOLITH OCULAR REFLEXES--PHYSIOLOGY AND ADAPTIVE CONTROL

前庭-眼反射(VOR)负责维持稳定性 头部运动时视网膜上的图像。许多行为上的 角度控制的特点和神经生理机制 VORS已被阐明。人们对此知之甚少 耳石-眼反射的组织。这些反应可以分为 根据代偿性眼球运动的类型分为三类 是由它们的激活引起的。眼球反转是指耳石-眼球 导致眼睛围绕视线扭转运动的反射 以响应动态和静态的头部横向倾斜。平移线性 VORS是响应动态线性运动而发生的眼部运动 头上的。由恒速旋转引起的眼球震颤 偏离垂直轴的结果是角速度信号由 耳石活动的中央处理。前庭神经传入 支配耳石不能区分导致 这三种回答中的每一种都是。该项目中描述的研究将 定义规范和自适应控制所涉及的机制 耳石--眼球反射。 三维和会聚眼球运动以及单个单元 警觉的松鼠将记录前庭核团的活动 猴双侧半规管失活前后的实验研究 通过一个封堵程序。与过程相关的假设 将测试如何区分倾斜和翻译反应。的作用 不规则的角速度信号、相位-张力响应 耳石传入放电和耳石的特定频率滤波 这些过程中的信号将被确定。生理学 耳石-眼球参与前庭核团神经元的特性 控件将被定义。耳石和半规管的形态特征 这些神经元的传入输入将被识别为与 平移和倾斜刺激。关于适应的研究由 与产生特定运动相关的视动刺激 耳石和半规管激活的轮廓将提供进一步的 有关用于区分这些响应的信号的信息。转让 使VOR增益适应于由不同的 半规管和耳石活动将确定 在这些途径中趋同，并定义产生过程中涉及的机制 来自耳石活动的角速度信号。 这项研究将加深我们对耳石-眼睛反应的理解。 以及短期VOR适应所涉及的过程。这些研究是 与人类功能障碍的诊断和治疗直接相关 耳石--眼球反射。

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.