NEURON DEATH IN CENTRAL NERVOUS SYSTEM DEVELOPMENT

新大脑皮层内在组织的本质是一个中心 发育神经生物学中的问题。成熟的新皮质为马赛克。 在功能和解剖方面的专业领域共享一个 基本的层状和柱状结构。中心问题是 新皮质是否是一个未指明的、统一的结构， 身份是由外部机构强加的，比如丘脑，或者是它 包含固有的本地身份，吸引和组织特定的 输入结构，并指定某些输出。国际贸易组织的发展 丘脑皮质投射的切线和板层特异性 将在两个实验条件下进行研究。在第一个 实验中，背侧新皮质的一个区域，主要是视觉皮质，将 在第一个丘脑轴突到达之前在子宫中被取出 皮质，发育、存活、成熟的投射模式和 将对丘脑轴突茎体积进行调查。在第二个 操纵，第四层的发育性删除和变化 大量的超颗粒层将使用有丝分裂来制造 缓蚀剂MAM(甲氧基乙酸甲酯)，平行分析。 这两种操作的目的都是删除目标 在轴突和目标种群的任何相互作用之前的种群，以及 从而揭示了在选择皮质和 传入丘脑皮质轴突的板层终末区域，以及 丘脑和大脑皮质之间的种群匹配机制。这个 这项工作的临床意义是直接的：除了提供 关于脑后皮质重组性质的基本信息 损害，我们将直接描述大脑皮质在 早期局部缺失，如可能发生的血管意外，或 在一次细胞毒性的侮辱之后。

The nature of the intrinsic organization of the neocortex is a central question in developmental neurobiology. The mature neocortex is a mosaic of functionally and anatomically specialized areas that share a fundamental laminar and columnar structure. The central question is whether the neocortex is an unspecified, unified structure on which local identity is imposed by an external agency like the thalamus or whether it contains intrinsic local identity that attracts and organizes particular input structure and specifies certain output. The development of the tangential and laminar specificity of thalamic projections to the cortex will be investigated in two experimental conditions. In the first experiment, a region of dorsal neocortex, principally visual cortex, will be removed in utero prior to the arrival of the first thalamic axons in the cortex, and the development, survival, mature projection pattern and volume of arbor of thalamic axons will be investigated. In the second manipulation, a developmental deletion of the layer IV and varying amounts of the supragranular layers will be made using a mitotic inhibitor, MAM (methylazoxymethanol acetate), with a parallel analysis. The intent of both of these manipulations is to delete the target population prior to any interaction of axon and target populations, and thus reveal any intrinsic specificity in the choice of cortical and laminar terminal area by incoming thalamocortical axons, and the mechanisms of population matching between the thalamus and cortex. The clinical significance of this work is direct: in addition to supplying basic information about the nature of cortical reorganization after brain damage, we will be directly describing what happens to the cortex after early local deletions, such as might happen with a vascular accident, or after a cytotoxic insult.