PATHS OF INDIVIDUAL AXONS IN THE VISUAL SYSTEM

视觉系统中各个轴突的路径

• 批准号: 3262739
• 负责人: ANNE C RUSOFF
• 金额: $ 3.75万
• 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/3262739
• 关键词: action potentials; autoradiography; axon; electron microscopy; eye regeneration; fish; fresh water environment; histochemistry /cytochemistry; histology; nervous system regeneration; neuroanatomy; optic nerve; 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.

该提案是对个体反应的解剖学研究 视网膜神经节细胞轴突对不同环境的反应 视神经损伤后再生的条件。 两种鱼，彩虹丽鱼和蓝鳃太阳鱼， 将用于 本课题共分三个部分：1）研究 模式和时间再生到一个recrom，这是缺乏 2）对视网膜轴突残留物的影响的研究 再生轴突分支上的电活动， 它们穿过受损的神经区域 在顶盖上形成新的顶生乔木; 部分视网膜切除术对顶盖影响的研究。 为 第一项研究中，每条鱼的一条视神经将被压碎， 直到退化轴突的碎片 消失了 然后视神经将被允许 再生到顶盖上， 在顶盖上重建视网膜定位图将是 这是通过在再生轴突的小群体中填充 赖氨酸钴使它们在视神经的切片中可见 神经和束以及整个扁平顶盖。 的 这些填充的轴突的位置将被比较， 到再生的时间过程和精确的 法线贴图 在第二次实验中，视神经将被压碎 然后在没有电的情况下再生， 活动（通过向眼睛内注射动作电位阻滞剂）或 在存在额外的电活动（由刺激引起）的情况下， 外部神经）。 再生的轴突将再次 通过用钴-赖氨酸填充它们的小组来可视化; 每个轴突的分支数量将被量化， 轴突穿过神经的受损区域， 终止于顶盖 这些点上的分支数 将与重建的精度进行比较， 视网膜定位图以确定轴突是否再生更多 精确地说有或没有电活动。 最后一项研究是 试图确定是否失去了一部分视网膜 传入导致成年鱼顶盖细胞的损失。 细胞在 顶盖边缘将用3 H胸苷标记， 视网膜切除术;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具有 消失了，表明神经元的实际损失。 这些研究 联合收割机来定义一些影响成功的参数 中枢神经系统的再生。