PHYSIOLOGY OF OCULOMOTOR PREMOTOR PATHWAYS

动眼运动前通路的生理学

• 批准号: 2161825
• 负责人: Robert A. McCrea
• 金额: $ 15.71万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-04-01 至 1996-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2161825
• 关键词: Saimiri; antidromic impulse; behavior test; brain electrical activity; cerebellum; head movements; neural information processing; neuroanatomy; neurons; neurophysiology; oculomotor nuclei; reticular formation; smooth pursuit eye movement; vestibular pathway; vestibuloocular reflex; visual pathways

The goal of the proposed studies is to elucidate the physiological characteristics of the pathways in the brain that are involved in the generation and voluntary control of the vestibulo-ocular reflex (VOR). Previous studies showed that monkeys utilize two mechanisms to voluntarily cancel their VOR (VORC). One mechanism involves a reduction in the head movement sensitivity of the secondary vestibular neurons that project to the abducens nucleus, the position-vestibular-pause (PVP) neurons. A second mechanism involves the generation of a smooth pursuit eye movement in the opposite direction to the VOR. The specific aims of the present proposal are to study the behavioral circumstances and neural mechanisms that are involved in the use of each of the mechanisms for voluntarily controlling the VOR. There are four specific aims. 1) In order to more precisely determine the behavioral circumstances in which the non-pursuit mechanism is recruited, behavioral experiments will be carried out in which the head will be passively perturbed during head free gaze pursuit of a visual target that is moving predictably and unpredictably. The gain of the VOR evoked by passive head perturbations will be studied as a function of head, gaze and target movement parameters. 2) The firing behavior of PVP neurons will be recorded in head free monkeys during gaze pursuit using the chronically implanted microwire in order to determine what signals are generated in secondary VOR pathways during head free gaze pursuit. 3) The possibility that inputs from the cerebellum or the reticular formation cause the head velocity sensitivity of secondary PVP neurons to decrease during VORC will be tested by recording from Purkinje cells in the flocculus and nodulus and neurons in the reticular formation near the abducens nucleus during unpredictable steps in head acceleration that are generated during VORC and during the VOR. 4) Several observations suggest that the abducens nucleus must receive inputs from cells whose activity is specifically related to smooth pursuit eye movements in order for the effects of residular head movement signals in VOR pathways to be canceled. An attempt will be made to determine whether the smooth pursuit neurons in the propositus nucleus and the adjacent medial vestibular nucleus whose activity is closely related to smooth pursuit eye movements project to the abducens nucleus by using the technique of spike triggered averaging of lateral rectus or abducens potentials combined with antidromic stimulation of the abducens nucleus.

拟议研究的目的是阐明生理学 大脑中参与的通路的特征 前庭眼反射（VOR）的产生和自主控制。 先前的研究表明，猴子利用两种机制来自愿地 取消他们的 VOR (VORC)。 一种机制涉及头部的减少 次级前庭神经元的运动敏感性投射到 外展核、前庭位置暂停 (PVP) 神经元。 一个 第二个机制涉及产生平滑的追踪眼球运动 与 VOR 的方向相反。 当前的具体目标 建议研究行为环境和神经机制 参与使用每种机制的自愿者 控制 VOR。 有四个具体目标。 1）为了更多 准确地确定不追求的行为环境 招募机制后，将进行行为实验，其中 在无头凝视追寻目标的过程中，头部会被动地受到干扰。 可预测和不可预测地移动的视觉目标。 的增益为 由被动头部扰动引起的 VOR 将作为一个函数进行研究 头部、凝视和目标运动参数。 2) 点火行为 PVP 神经元将在无头猴子的凝视追踪过程中被记录 长期植入的微丝以确定什么信号 在无头注视追踪过程中，在次要 VOR 路径中产生。 3) 的 来自小脑或网状结构的输入的可能性 导致次级 PVP 神经元的头部速度敏感性降低 VORC期间将通过浦肯野细胞的记录进行测试 绒球和结节以及神经元在网状结构附近 在头部加速的不可预测的步骤中外展核 在 VORC 和 VOR 期间生成。 4) 一些观察表明 外展核必须接收来自其活动的细胞的输入 特别与平滑的眼球追踪运动相关，以便 VOR 路径中残余头部运动信号的影响被消除。 将尝试确定平滑追踪神经元是否 前庭核和邻近的前庭内侧核 活动与平滑追踪眼球运动投射密切相关 外展核通过使用尖峰触发平均技术 外直肌或外展肌电位与逆向刺激相结合 外展核。