Eye Movement Maps in Superior Colliculus

描述（由申请人提供）：哺乳动物上丘（SC）是一个皮层下结构，整合视觉和其他感觉信息，启动眼睛和头部的定向运动。SC组织的一个基本特征是感觉输入和运动输出的表征在地形上排列和对齐。虽然在理解SC中视觉表征的发展方面取得了很大进展，但运动地图是如何形成并与视觉地图对齐的仍然未知。为了利用小鼠现有的遗传工具，研究人员建议对小鼠SC中运动图谱的组织和发展进行全面的研究。首先，将在SC的深层进行电微刺激，以唤起小鼠的眼跳样快速眼球运动。通过系统地改变SC中的刺激点并确定诱发运动的幅度和方向，可以揭示眼动图的地形组织。单单元记录也将在深层进行，以确定单个神经元如何编码眼球运动方向和振幅，以及这些运动场如何在小鼠SC中被映射。同样的实验将在出生时被剥夺视觉经验的小鼠和现有的转基因小鼠品系中进行，这些小鼠在SC中改变了视觉地图。这些实验将确定视觉输入是否为运动地图的发展和视觉运动对齐提供了指导性信号。总之，拟议的实验将提供小鼠SC深层的第一个系统映射，并启动影响感觉运动发育因素的研究。这些研究将对理解和潜在治疗由神经元连接错误引起的人眼运动障碍和其他疾病具有重要意义。6

DESCRIPTION (provided by applicant): The mammalian superior colliculus (SC) is a subcortical structure that integrates visual and other sensory information to initiate orienting movements of the eyes and head. A fundamental feature of SC organization is that the representations of sensory inputs and motor outputs are topographically arranged and aligned. While great progress has been made in understanding the development of the visual representation in the SC, how the motor maps are formed and aligned with the visual map remains unknown. In order to take advantage of the available genetic tools in mice, the investigators propose to perform a comprehensive investigation of the organization and development of motor maps in the mouse SC. First, electrical microstimulation will be conducted in the deep layers of the SC to evoke saccade-like rapid eye movements in mice. The topographic organization of the eye movement map will be revealed by systematically varying the stimulation sites in the SC and determining the amplitude and direction of the evoked movements. Single-unit recording will also be performed in the deep layers to determine how individual neurons encode eye movement direction and amplitude, and how such movement fields are mapped in the mouse SC. Second, the same experiments will be performed in mice deprived of visual experience from birth and in an existing transgenic mouse line that have altered visual maps in the SC. These experiments will determine whether visual inputs provide an instructive signal for motor map development and visuomotor alignment. Together, the proposed experiments will provide the first systematic mapping of the deep layers of the mouse SC and initiate studies on factors influencing sensorimotor development. These studies will have important implications for the understanding and potential treatment of human eye movement disorders and other diseases that result from miswiring of neuronal connections. 6