Eye Movement Control-Role of Brain Stem Neurons

描述(申请人提供)：本项目的总体目标是了解感官信号是如何转化为控制运动的命令的。更具体地说，拟议的实验研究了灵长类上丘(SC)和桥延髓网状结构在控制眼睛和头部的定向运动中的作用。 第一组实验有两个目标：1)描述在协调的眼头运动和在没有凝视转移的情况下，头部运动时脑桥延髓网状结构的顶盖接受区神经元的功能特性；2)研究微刺激这些脑桥延髓区域对眼睛和头部运动的影响。这些研究的目标是从SC中间层接受密集投射的脑干区域，也有高密度的神经元投射到支配颈部肌肉的脊髓区域。 在第二组实验中，我们将可逆地灭活桥脑桥旁顶部网状结构中的神经元，以观察这些细胞的活动是对协调眼头运动的眼睛和头部成分至关重要，还是对在没有凝视转移的情况下进行的头部运动至关重要。 第三组实验有三个目标：a)使用与记录桥延髓区域细胞相同的行为任务记录上丘神经元；b)使用一种搜索策略，增加在上丘更深层发现与头部运动相关的活动的细胞的概率；c)检查上丘神经元在大规模凝视转移时观察到的异常眼速曲线的可能贡献。 最后一组实验使用了一种新的方法，在凝视转移期间改变眼睛和头部运动的速度和幅度，同时记录脑桥延髓神经元的活动，试图了解凝视、眼睛和头部的幅度和速度是如何在脑桥延髓神经元的活动中编码的。

DESCRIPTION (provided by applicant): The overall goal of this project is to understand how sensory signals are translated into commands for the control of movements. More specifically, the proposed experiments study the role of the primate superior colliculus (SC) and the pontomedullary reticular formation in the control of orienting movements of the eyes and head. The first set of experiments has two goals: 1) to describe the functional properties of neurons in the tecto-recipient regions of pontomedullary reticular formation during coordinated eye-head movements and during head movements in the absence of a gaze shift; and 2) to study the effects of microstimulation of these pontomedullary regions upon eye and head movements. These studies target the brainstem areas that receive dense projections from intermediate layers of SC and also have a high density of neurons projecting to regions of the spinal cord innervating the neck muscles. In the second set of experiments neurons in the rostral paramedian pontine reticular formation will be reversibly inactivated to see if the activity of these cells is critical for the eye and head components of coordinated eye-head movements or for head movements made in the absence of a gaze shift. The third set of experiments has three goals: a) to record from neurons in the superior colliculus using the same behavioral tasks that were used to record from cells in pontomedullary regions; b) to use a search strategy that will increase the probability of finding cells in deeper layers of superior colliculus with activity related to head movements; and c) to examine the possible contribution of collicular neurons to the unusual eye velocity profiles observed during large gaze shifts. The final set of experiments uses a novel method of varying the speed and amplitude of eye and head movements during a gaze shift while recording the activity of pontomedullary neurons in an attempt to understand how gaze, eye and head amplitude and velocity is encoded in the activity of pontomedullary neurons.