PATHS OF INDIVIDUAL AXONS IN THE VISUAL SYSTEM

视觉系统中各个轴突的路径

• 批准号: 3262736
• 负责人: ANNE C RUSOFF
• 金额: $ 6.67万
• 依托单位: MONTANA STATE UNIVERSITY - BOZEMAN
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-09-01 至 1991-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3262736
• 关键词: action potentials; autoradiography; axon; electron microscopy; eye regeneration; fresh water environment; histochemistry /cytochemistry; histology; nervous system regeneration; neuroanatomy; radiotracer; retina; retinal ganglion; superior colliculus; synapses; tritium; visual pathways

This proposal is an anatomical study of the responses of individual axons of retinal ganglion cells to different environmental conditions as they regenerate after damage to the optic nerve. Two species of fish, the rainbow cichlid and the bluegill sunfish, will be used. The project is divided into 3 parts: 1) a study of the pattern and timing of regeneration onto a recrom which is devoid fo residual retinal axonal material 2) a study of the effects of electrical activity on the branching of regenerating axons both as they make their ways through the damaged region of the nerve and as they make new terminal arbors on the tectum; and 3) a study of the effects of partial retinal ablation on the tectum. For the first study one optic nerve in each fish will be crushed and kept off the tectum until the debris from the degenerating axons has disappeared. Then the optic nerve will be allowed to regenerate onto the tectum, and the time and precision of reestablishment of a retinotopic map on the tectum will be determined by filling small groups of regenerated axons with cobaltouslysine to visualize them both in sections of the optic nerve and tract and on the whole flat-mounted tectum. The positions of these filled axons will be compared both with respect to the time course of regeneration and to the precision of the normal map. For the second study the optic nerve will be crushed and then allowed to regenerate either in the absence of electrical activity (by injecting an actionpotential blocker into the eye) or in the presence of extra electrical activity (caused by stimulating the nerve externally). Again the regenerated axons will be visualized by filling small groups of them with cobaltous-lysine; the number of branches per axon will be quantified both as the axons cross the damaged region of the nerve and as they terminate in the tectum. The number of branches at these points will be compared with the precision of reestablishment of the retinotopic map to determine whether axons regenerate more precisely with or without electrical activity. The final study is an attempt to determine whether loss of a portion of retinal afferents leads to loss of tectal cells in adult fish. Cells at the tectal margins will be labeled with 3Hthymidine before partial retinal ablation; later the tecta will be sectioned and examined radioautographically to determine whether the labeled cells have disappeared, indicating actual loss of neurons. These studies combine to define some of the parameters which affect successful regeneration in the central nervous system.

这个建议是对个体反应的解剖学研究。 视网膜神经节细胞对不同环境的轴突 视神经受损后再生时的情况。 两种鱼，彩虹旗鱼和蓝鳍太阳鱼， 将会被使用。本课题共分为三个部分：1)研究 在缺失的回旋上再生的模式和时间 残留的视网膜轴突材料2)影响的研究 再生轴突分支的电活动 它们穿过受损的神经区域 当它们在顶盖上形成新的末端茎时；3)a) 视网膜部分切除对顶盖影响的研究。为 第一项研究中，每条鱼的一条视神经将被挤压 直到退化轴突的碎片出现在顶盖之外 已经消失了。然后视神经将被允许 在顶盖再生，时间和精确度 在顶盖重建视网膜定位图将是 通过将少量再生轴突填充到 用钴-赖氨酸在光学切片上显示它们 神经和束，以及整个平装的顶盖。这个 这些被填充的轴突的位置将与 到再生的时间进程和到 法线贴图。在第二项研究中，视神经将被挤压 然后在没有电的情况下允许再生 活动(通过向眼睛内注射动作电位阻滞剂)或 在存在额外电活动(由刺激引起)的情况下 外部的神经)。再说一次，再生的轴突 通过用赖氨酸钴填充它们中的一小群进行可视化； 每个轴突的分支数量将被量化为 轴突穿过受损的神经区域，当它们 终止于顶盖。这些点上的分支机构数量 将与重建 视网膜定位图以确定轴突是否再生更多 精确地有或没有电活动。最后的研究是一项 尝试确定视网膜的一部分是否丢失 传入导致成鱼顶盖细胞的丧失。单元格位于 顶盖边缘用~3H-胸腺嘧啶核苷标记 视网膜消融术；随后将对顶盖进行切片和检查 放射自显影以确定标记的细胞是否有 消失了，表明实际上神经元已经丧失了。这些研究 组合以定义影响成功的一些参数 中枢神经系统的再生。