MECHANISMS OF VISUAL SYSTEM MATURATION

视觉系统成熟的机制

• 批准号: 3259725
• 负责人: Vivien A Casagrande
• 金额: $ 8.41万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1983
• 资助国家: 美国
• 起止时间: 1983-12-01 至 1987-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3259725
• 关键词: afferent nerve; axon; cell death; cell differentiation; dendrites; denervation; electron microscopy; evolution; histology; innervation; lateral geniculate body; microscopy; neuronal transport; newborn animals; visual cortex; visual pathways

The major objective is to define mechanisms by which patterns of visual connections are established during development. This program is a continuation of our efforts to explain how lateral geniculate nucleus (LGN) layers form. We will use the 6 layered tree shrew LGN as a model system since all cell 6 layers develop postnatally. The 3 specific aims examine how retinal afferents influence cell layer formation. In Aim 1, studies are proposed to elucidate the sequence and details of connections of developing LGN cells. Prenatal studies utilizing HRP and 3H amino acid tracers will examine initial retinal afferent segregation. Postnatal studies utilizing HRP will examine the morphology of individual terminal arbors of retinal, tectal, and cortical axons within the nucleus. Also, tracers will be used to examine the sequence of LGN innervation of striate cortex. Aim 2 will provide information on the regulation of cell number and cell death in the retina and LGN during LGN layer formation. Finally, Aim 3 will test different ways in which retinal afferents might trophically influence LGN targets by 1) manipulating optic nerve activity (darkrearing or tetrodotoxin injection), 2) blocking of axoplasmic transport (colchicine), 3) damaging discrete retinal regions. In all cases, LGN cell layer development and cytologic differentiation will be examined to determine the effectiveness of these manipulations. Together these studies should provide a clearer picture of how lamination develops within the LGN; results which in turn could provide clues as to basic rules by which sensory afferents influence the cytologic differentiation and topography of postsynaptic targets in a highly ordered system. As such, these studies are relevant not only to understanding basic mechanisms of normal visual development, but also clinically to understanding disorders that may effect that development.

主要目标是定义视觉模式的机制 在开发过程中建立了联系。 这个程序是 延续我们为解释侧向元化核如何（LGN）的努力 图层形式。 我们将使用6个分层的树sh lgn作为模型系统 由于所有细胞6层都会在产后发展。 三个特定目的检查 视网膜传入如何影响细胞层的形成。 在AIM 1中，研究 建议阐明序列和连接的序列和细节 发展LGN细胞。 利用HRP和3H氨基酸的产前研究 示踪剂将检查初始的视网膜传入分离。 产后 利用HRP的研究将检查单个终端的形态 核内视网膜，张力骨和皮质轴突的轴向。 还， 示踪剂将用于检查条纹的LGN神经支配的序列 皮质。 AIM 2将提供有关单元编号调节的信息 在LGN层形成期间，视网膜和LGN中的细胞死亡。 最后， AIM 3将测试视网膜传入可能会进行营养的不同方式 通过1）操纵视神经活性来影响LGN目标（黑暗 或注射四毒素），2）轴质转运的阻塞 （秋水仙碱），3）破坏离散视网膜区域。 在所有情况下，LGN细胞 将检查层开发和细胞学分化 确定这些操纵的有效性。 这些研究共同提供了更清晰的层压图 在LGN内发展；结果又可以提供有关的线索 感觉传入影响细胞学的基本规则 高度有序的突触后目标的分化和地形 系统。 因此，这些研究不仅与理解有关 正常视觉发展的基本机制，但在临床上也 了解可能影响这种发展的疾病。