MULTIDIMENSIONAL DYNAMICS OF VESIBULAR-OCULAR REFLEX

前庭系统产生的代偿性眼球运动是 对来自所有半圆形的信息进行协调“整合”的结果 运河和耳石。持续性水平眼球震颤的研究 在偏离垂直轴旋转和俯仰头部的同时生成 旋转显示了耳石和垂直半规管是如何 可以通过耦合到速度存储装置来产生水平眼震 积分器。在过去的一年中发现了一个特别引人注目的现象 授权期是与以下各项相关联的存储之间存在耦合 水平面和垂直面的眼球震颤 由于引力场的变化而发生了显著变化。这表明 速度存储将由更高的维度来表示 具有建立引力的系统状态的动力系统 解释头部运动和头部运动的独立坐标基础 视觉上的环绕。这项研究的目的是扩展模型 视觉-前庭在同一平面上相互作用的前庭-眼反射 前庭-眼反射的三维表示 可以用来解释速度存储在复杂的旋转过程中的作用 头部。具体地说，我们将确定峰值速度和上升速度 眼球震颤后垂直视动的下降时间常数 动物处于不同状态时的纯水平视动刺激 与重力有关的方向。这应该使我们能够获得 水平和垂直之间耦合的定量估计 速度存储积分器的激励方式。活动将是 从二阶垂直和水平方向进行细胞外记录 前庭核团中的单位。二阶垂直单位活动 然后与非垂直轴期间的垂直眼速进行比较 旋转以确定交叉耦合对垂直眼的影响 体位和眼震。这项研究应该给出一个数学框架 在其中可以查看Head和 在所有平面上环绕移动。我们也应该更清楚地认识到 前庭眼球交叉耦合的重要参数 反射并更好地理解其功能意义 三维速度存储。

Compensatory eye movements generated by the vestibular system are the result of a coordinated "integration" of information from all semicircular canals and the otoliths. A study of continuous horizontal nystagmus generated during off vertical axis rotation and pitching the head while rotating has shown how the otoliths and the vertical semicircular canals can generate horizontal nystagmus by coupling to the velocity storage integrator. A particularly striking phenomena discovered during the last grant period is that there is a coupling between storage associated with nystagmus in the horizontal and vertical planes and that it is significantly altered by changes in the gravitational field. This suggests that velocity storage would be represented by a higher dimensional dynamical system with the states of that system establishing a gravity dependent coordinate basis for interpreting head movement and movements of the visual surround. The aim of this research is to extend the model of the vestibulo-ocular reflex for visual-vestibular interaction in one plane to a three dimensional representation of the vestibulo-ocular reflex that can be used to explain the role of velocity storage in complex rotations of the head. Specifically, we will determine the peak velocity and rising and falling time constants of vertical optokinetic after nystagmus following pure horizontal optokinetic stimulation when the animal is in different orientations with regard to gravity. This should enable us to obtain quantitative estimates of the coupling between the horizontal and vertical modes of excitation of the velocity storage integrator. Activity will be recorded extracellularly from second order vertical as well as horizontal units in the vestibular nuclei. The second order vertical unit activity will then be compared to the vertical eye velocity during off-vertical axis rotation to determine what effect cross coupling has on vertical eye position and nystagmus. This research should give a mathematical framework in which to view the dynamic transformations that occur for head and surround movement in all planes. We should also have a clearer idea of the parameters that are important for cross coupling in the vestibulo-ocular reflex and have a better understanding of the functional significance of velocity storage in three dimensions.