MULTIDIMENSIONAL DYNAMIC OF THE VESTIBULO OCULAR REFLEX

描述（由申请人提供）：这个项目的目标是模拟前庭系统如何在运动过程中维持双眼在空间的固定，这些运动会引起头部和身体的线性和角加速度。我们假设角状和线性前庭-眼反射（aVOR和IVOR）可以通过激活代偿和空间定向机制来表征。在我们提出的工作中，我们将通过结合版本和收敛来扩展这些想法，以研究双眼观看是否也可以根据补偿和定向理论来表征。提出了一种利用旋转场线圈系统记录三维双目眼球运动的方法。提出了一种基于头部坐标系下的收敛矩阵和版本矩阵来计算双眼旋转的新数学方法。已经提出的算法将利用这些矩阵和从头部坐标帧原点到每只眼睛的向量来计算凝视注视点。初步研究表明，经过训练，猴子可以在视野的不同位置注视目标，以校准每只眼睛。在第一个特定的瞄准中，猴子将沿着鼻枕轴和其他基本轴以0.5-4赫兹的速度线性加速，同时从头部框架的原点以不同的角度和距离观察空间中的目标。这将测试IVOR的补偿特性。在具体目标2中，我们将利用旋转平移（TWR）来确定低频线性加速度如何影响IVOR的双目凝视特性，我们假设这将由双目定向机制产生，该机制将倾向于将双目固定与净重力惯性加速度（GIA）对齐。在具体目标3中，猴子将被测试使用沿重力加速度轴的线性加速度。我们假设这将引起代偿性动眼肌反应，而没有通常伴随的中频定向反应。我们期望补偿反应将在空间中保持固定的凝视点，而方向反应将倾向于使眼睛或眼速与最终的GIA对齐。我们还将建模三维补偿和取向收敛和版本的相互作用，如具体目标4所述。当这项研究完成后，我们将有一个定量模型来研究前庭系统如何在运动时维持双眼凝视的稳定性。

DESCRIPTION (provided by applicant): The objective of this project is model how the vestibular system contributes to maintaining binocular fixation in space during motions that induce linear and angular accelerations of the head and body. We have hypothesized that the angular and linear vestibulo-ocular reflexes (aVOR and IVOR) can be characterized through the activation of compensatory and spatial orientation mechanisms. In the proposed work, we will extend these ideas by combining version and vergence to study whether binocular viewing can also be characterized in terms of the compensatory and orienting theory. A methodology for recording binocular eye movements in three dimensions using a rotating field coil system has been developed. A new mathematical methodology has been proposed to obtain the rotation of the two eyes in terms of convergence and version matrices in head coordinates. Algorithms have been proposed that will utilize these matrices and a vector from the head coordinate frame origin to each eye to compute gaze fixation points. Preliminary studies indicate monkeys can be trained to fixate targets at various positions in the visual field to calibrate each eye. In the first specific aim, monkeys will be linearly accelerated along naso-occipital and other cardinal axes at 0.5-4 Hz, while viewing targets in space at various angles and distances from the origin of the head frame. This will test the compensatory properties of the IVOR. In specific aim 2, we will utilize translation while rotating (TWR) to determine how low frequency linear acceleration affects the binocular gaze characteristics of the IVOR, which we hypothesize will be generated by the binocular orientation mechanisms that will tend to align binocular fixation with the net gravito-inertial acceleration (GIA). In specific aim 3, monkeys will be tested using linear acceleration along the axis of the gravitational acceleration. We hypothesize that this will induce compensatory oculomotor responses without the usual concomitant orientation responses at midband frequencies. We expect that compensatory response will maintain fixed gaze points in space while orientation responses will tend to align the eyes or eye velocity with the resultant GIA. We will also model the three-dimensional compensatory and orientation convergence and version interaction as described in specific aim 4. When the study is completed, we will have a quantitative model of how the vestibular system contributes to maintenance of binocular gaze stability while moving.