MECHANISMS OF VISUAL SYSTEM MATURATION

本研究的总体目标是了解 负责细胞模式发展的机制 和神经系统中的连接。 的发展 外侧膝状体核（LGN）的层次和联系 提供了一个适当的系统，用于调查这些 机制，因为正常的系统是精确组织和 它的组织和发展的许多方面都很好- 记录在案。 我们对这个系统的研究使我们假设 提出层流形成机制的模型。 每个 的具体目标是为了测试这个模型的各个方面， 树鼩和雪貂正在发育的LGN。 具体目标1将决定发展是否 传入神经和树突的生长顺序支持这一观点 这些过程以系统的方式相互作用， 层间间隙 具体目标2将探讨影响 视网膜传入神经对LGN细胞生长和间距的影响：a） 阻断轴浆转运; B）损伤离散视网膜 区域;以及c）检查区域和层流变化， 胆碱能过程的个体发生。 具体目标3将 检查发育中的皮质和丘的影响， 关于层间空间形成的预测：a）删除这些 输入; B）阻断动作电位;以及c）单眼 在发育早期摘除动物的核。 最后，具体 目的4探讨建立体外细胞培养方法的可行性 模型（器官型培养系统）的LGN检查 细胞结构和连接的发展 控制条件。 总之，这些研究将阐明层流的机制， 在LGN的发展。 这些结果可以反过来提供 关于产生有序细胞的基本规则的线索 神经系统中的模式和连接。 这些研究 不仅有助于理解 正常的视觉系统发展，而且要了解 可能影响其发展的临床疾病。

The overall objective of this research is to understand the mechanisms responsible for the development of cellular patterns and connections in the nervous system. The development of layers and connections in the lateral geniculate nucleus (LGN) provides an opportune system for investigation of these mechanisms, since the normal system is precisely organized and many aspects of its organization and development are well- documented. Our work on this system has led us to postulate a model that suggests the mechanisms of laminar formation. Each of the specific aims is designed to test aspects of this model in the developing LGN of tree shrews and ferrets. SPECIFIC AIM 1 will determine whether the developmental sequence of growth of afferents and dendrites supports the idea that these processes interact in a systematic way to produce interlaminar spaces. SPECIFIC AIM 2 will explore the influence of retinal afferents on LGN cell growth and spacing by: a) blocking axoplasmic transport; b) damaging discrete retinal regions; and c) examining for regional and laminar variations in the ontogenesis of cholinergic processes. SPECIFIC AIM 3 will examine the influence of developing cortical and collicular projections on interlaminar space formation by: a) deleting these inputs; b) blocking action potentials; and c) monocularly enucleating animals early in development. Finally, SPECIFIC AIM 4 will explore the feasibility of establishing an in vitro model (organotypic culture system) of the LGN to examine the development of cytoarchitecture and connections under controlled conditions. Together, these studies will clarify the mechanism of laminar development in the LGN. These results could, in turn, provide clues concerning the basic rules the produce orderly cellular patterns and connections in the nervous system. These studies are relevant not only to understanding basic mechanisms of normal visual system development, but also to understanding clinical disorders that may affect that development.