OCULOMOTOR SYSTEM--NEURAL STRUCTURE AND FUNCTION

描述：（改编自申请人的摘要。）前庭眼 反射（VOR）对于正常的视力是必不可少的，因为它的作用是 - 稳定视网膜上的视觉图像以对抗头部的运动， 身体 头部和身体的运动由半规管感知 （角加速度计）和耳石器官（线性加速度计）。 最短的神经通路是由初级神经元和次级神经元组成的3-神经元弧。 受体神经元、前庭核中的中间神经元和运动神经元 驱动眼部肌肉的神经系统 反射非常快， 在猴子身上表现出短至8毫秒的潜伏期。 一般来说，如果一个 观察远处的目标，补偿性眼球运动应该是 大小相等但方向相反的扰动头 移动（增益- -1）。 然而，人们经常在 个人以外的空间，例如，拿在手里的东西。 对于近距离目标 例如，VOR没有单一的正确增益，因为轴 头部旋转的轴不能与眼睛的旋转轴重合。 通常旋转中心在眼睛后面（例如，在脊柱上方 用于头部向左或向右转动的绳索），并且几何考虑表明， VOR的增益必须大于1，才能完全稳定目视 形象 头部绕着相对于眼睛移位的轴线运动， 眼睛在空间中的平移和旋转，并产生 耳石以及耳道传入信号。 然而，耳石和耳道 信号不足以确定正确的VOR增益;信息 目标位置也需要。 这项提议的中心目标是 识别VOR增益计算发生的位置，以及 然后分析神经通路和生理机制， 产生补偿性眼球运动。 这项工作涉及的问题， 我们是如何确定空间位置的， 双眼控制眼球运动。

DESCRIPTION: (Adapted from the applicant's abstract.) The vestibulo-ocular reflex (VOR) is essential for normal visual acuity because it acts to stabilize visual images on the retina against movements of the head and body. Head and body movements are sensed by the semicircular canals (angular accelerometers) and the otolith organs (linear accelerometers). The shortest neural pathway is a 3-neuron arc consisting of primary receptor neurons, interneurons in the vestibular nuclei, and motoneurons that drive the muscles of the eye. The reflex is extremely fast, exhibiting a latency as short as 8 ms in the monkey. In general, if one is viewing a target in the distance, the compensatory eye movements should be equal in magnitude but opposite in direction to the perturbing head movement (Gain - -1). Frequently, however, one views an object in extrapersonal space, e.g., something held in the hands. For near targets such as these, there is no single correct gain for the VOR, since the axis of head rotation cannot be coincident with the rotational axes of the eyes. Normally the center of rotation is behind the eyes (e.g., above the spinal cord for left or right head turns), and geometric considerations show that the gain of the VOR must be greater than one to fully stabilize a visual image. Head movements about axes displaced with respect to the eye cause translation as well as rotation of the eyes in space, and give rise to otolith as well as canal afferent signals. However, the otolith and canal signals are insufficient to determine the correct VOR gain; information about target location is also required. The central goal of this proposal is to identify the site(s) where the computation of VOR gain occurs, and then to analyze the neural pathways and physiological mechanisms involved in producing compensatory eye movements. This work relates to issues of how we determine spatial location, and to neural mechanisms involved in binocular control of eye movements.