MULTIDIMENSIONAL DYNAMICS OF THE VESTIBULO-OCULAR REFLEX

根据重力原因改变头部的方向 眼球代偿性运动的戏剧性变化 视觉和前庭系统。我们最近制定了三个 中枢神经系统如何整合的维度模型 来自半规管、视觉系统和 耳石解释代偿性眼球运动的反应 在重力环境中绕任意轴旋转。我们 还表明，重力具有使 速度存储的主轴朝向空间垂直。 这项研究的目的是从数学上刻画 作为函数的三维速度存储积分器 重力来预测这些方位的变化。我们还打算 刻画模型中的各种动力系统算符 它与速度存储积分器相连。具体来说，我们 将确定速度的特征值和特征向量 适用于多种磁头取向的存储积分器 关于地心引力。这将通过倾斜的方式来完成 头的给定位置的视动刺激和 确定视动力与头部的相对角度 后眼球震颤(OKAN)速度沿直线下降 太空。这将是特征向量。与之相关的特征值 这个本征向量将是时间常数的倒数 奥坎的腐烂。我们还将提供非垂直轴的旋转 关于通过头部的任意角度来确定最佳 在三个平面中产生补偿眼速 尺寸。活动将从第二秒开始进行细胞外记录 与垂直和水平半规管有关的顺序 斜视运动期间和斜视运动后前庭核团的单位 眼球震颤和视动性后眼球震颤。我们建议确定 这些单元在特征向量和特征值编码中的作用 速度存储和产生眼睛的三个组成部分 在这些类型的刺激下的速度。我们还将测试这些 偏离垂直轴绕不同轴旋转时的单位 通过头部确定最优平面进行估算 耳石产生的头部速度。实验结果 将与前庭的三维模型相关- 眼睛反射。这项研究应该让我们更好地理解 在复杂的头部过程中如何产生补偿性眼动 动静。它还应该阐明 速度存储积分器生成这些运动。

Changing the orientation of the head with regard to gravity causes a dramatic change in ocular compensatory movements generated by the visual and vestibular systems. We have recently formulated a three dimensional model of how the central nervous system integrates information from the semicircular canals, visual system and otoliths to explain compensatory eye movements in response to rotations about arbitrary axes in a gravitational environment. We have also shown that gravity has the effect of orienting the principal axes of velocity storage toward the spatial vertical. The aim of this research is to mathematically characterize the velocity storage integrator in three dimensions as a function of gravity to predict these changes in orientation. We also intend to characterize the various dynamical system operators in the model that couple to the velocity storage integrator. Specifically, we will determine the eigenvalues and eigenvectors of the velocity storage integrator for a wide range of orientations of the head with regard to gravity. This will be done by giving oblique optokinetic stimuli for a given position of the head and determining the angle relative to the head where the optokinetic after-nystagmus (OKAN) declines along a straight line in velocity space. This will be the eigenvector. The eigenvalue associated with this eigenvector would be the inverse of the time constant of the decay in OKAN. We will also give off-vertical axis rotation about arbitrary angles through the head to determine the optimal planes for generating compensatory eye velocity in three dimensions. Acitivity will be recorded extracellularly from second order vertical as well as horizontal semicircular canal related units in the vestibular nuclei during and after oblique optokinetic nystagmus and optokinetic after-nystagmus. We propose to determine the role of these units in coding the eigenvectors and eigenvalues of velocity storage and in generating the three components of eye velocity during these type of stimuli. We will also test these units during off-vertical axis rotatation about different axes through the head to determine the optimal planes for estimating head velocity generated by the otoliths. Experimental findings will be related to the three dimensional model of the vestibulo- ocular reflex. This research should give a better understanding of how compensatory eye movements are generated during complex head movements. It should also elucidate the functional role of the velocity storage integrator in generating these movements.