EARLY OLFACTORY DEVELOPMENT

提出的实验检查了中央继电器的发展 嗅觉系统：嗅球、前嗅核和 初级嗅觉皮层。嗅觉系统已被选定为数个 理由：它的功能在幼年哺乳动物中相当重要，而且其作用很明显 层状组织促进早期大脑的定量研究 成长。这些项目采用了灰色短尾负鼠 Monodelphis 国内。 Monodelphis 幼崽出生时处于非常不成熟的状态，并且， 物种缺乏育儿袋，很容易进行早期实验 操纵。这些特征，加上物种生长缓慢， 提供一种独特适合早期检查的哺乳动物制剂 发展互动。解决的问题包括：A) 肾小球如何 发展？信息传递到区域的中枢神经系统 被称为肾小球，每个肾小球都被认为接受专门的 有关刺激不同方面的信息。因此， 肾小球输入的发育分离可能会组织 信息流遍及整个系统。存在数据表明两者 外周因素和中枢因素负责肾小球 组织。我们计划通过检查序列来测试这些想法 神经元和神经胶质细胞的发育。 B) 基本模式是什么 中央嗅觉投射的生长和成熟？令人惊讶的是 对于大多数人来说，人们对细胞形态的发展知之甚少。 嗅觉系统中的主要神经元类别。我们计划审查 使用几种新技术开发细胞形状。 C）有多重要 灯泡的发育是在形成更高阶结构吗？事实 球茎是前脑中最早熟的区域之一 开发已被用来表明存在“串行感应” 系统，外围感应灯泡，然后灯泡起作用 组织后续接力活动。我们将通过删除来测试这个概念 生命早期的嗅球并检查随后的生长 较高的加工区域。 D) 传入活动有多重要 高阶结构的形成？早期的感觉操纵有 已被证明对我国的发展具有深远的影响 嗅球。 Monodelphis 由于出生时极度不成熟， 提供了一个检查功能激活作用的机会 贯穿整个体系的形成时期。在一起， 研究将提供有关大脑正常过程的重要信息 发展及其控制受内部和外部因素的影响。

The experiments proposed examine the development of the central relays in the olfactory system: the olfactory bulb, anterior olfactory nucleus and primary olfactory cortex. The olfactory system has been chosen for several reasons: its function is quite important in young mammals and its clear laminar organization facilitates quantitative studies of early brain growth. The projects employ the gray, short-tailed opossum Monodelphis domestica. Monodelphis pups are born in a very immature state, and, as the species lacks a pouch, are quite accessible to early experimental manipulation. These features, coupled with the slow growth of the species, offer a mammalian preparation uniquely suited for examinations of early developmental interactions. Issues addressed include: A) How do glomeruli develop? Information is passed to the central nervous system in regions known as glomeruli, each of which are thought to receive specialized information about different aspects of stimuli. Therefore, the developmental segregation of inputs into glomeruli may organize information flow throughout the entire system. Data exists suggesting both peripheral and central factors are responsible for glomerular organization. We plan to test these ideas by examining sequences of development of both neurons and glia. B) What are the basic patterns of growth and maturation in the central olfactory projections? Surprisingly little is known about the development of cellular morphology for most of the major neuron classes in the olfactory system. We plan to examine the development of cell shape using several new techniques. C) How important is bulb development in the formation of higher order structures? The fact that the bulb is one of the most precocious regions of the forebrain to develop has been used to suggest that there is a "serial induction" in the system, with the periphery inducing the bulb and the bulb then acting to organize subsequent relays. We will test this notion by removing the olfactory' bulb during early life and examining the subsequent growth of the higher processing areas. D) How important is afferent activity in the formation of higher order structures? Early sensory manipulations have been demonstrated to have far-reaching effects on the development of the olfactory bulb. Monodelphis, due to its extreme immaturity at birth, offers an opportunity to examine the role of functional activation throughout the entire formative period of the system. Together, the studies will provide important information about normal processes of brain development and their control by both internal and external factors.