CELLULAR PHYSIOLOGY OF CORTICAL DEVELOPMENT

本项目将探讨大脑皮层突触的基本机制 队形。三个特定的突触，两个兴奋性的和一个抑制性的， 将在海马皮层的器官培养中进行研究。脑区 新生大鼠的切片将在生活状态下进行培养和研究 使用延时激光共聚焦显微镜。荧光染料和离子 指示器将用于可视化细胞结构和活动 模式。将使用电生理方法来评估和 操纵突触功能。对细胞进行生理学检查 免疫组织化学和电子固定后重新鉴定 显微镜研究。 该项目将从详细的解剖学、免疫组织化学和 三种胚胎体外发育的电生理基线研究 突触：(1)兴奋性苔藓纤维与锥体细胞的突触 海马CA3区，(2)兴奋性Schaffer侧支纤维突触 投射到CA1区的锥体细胞；(3)篮子抑制性突触 CA1区锥体细胞。培养的切片系统将 然后用来追问四个主要的生理学和 突触形成的动力学： 1.轴突生长锥如何在皮质组织环境中导航？ 2.轴突生长锥和未成熟的树突是如何形成初始的 接触导致突触形成？ 3.初次接触和接触之间的顺序和时间安排是什么 功能突触的建立？ 4.电活动如何影响分子的形成和稳定性 突触？ 关于这些问题中的每一个都有几个具体的假设 测试过。 拟议的研究应该为神经异常提供洞察力 发育包括出生缺陷、学习障碍和精神疾病 智力迟缓。他们还可能帮助建议医疗程序 预防或逆转与创伤相关的神经功能障碍 卒中。最后，他们可能会阐明正常的发育基础 衰老对神经系统功能的影响以及对退行性疾病的影响 帕金森氏症和阿尔茨海默氏症等疾病。

This project will address the basic mechanisms of cortical synapse formation. Three specific synapses, two excitatory and one inhibitory, will be studied in organotypic cultures of hippocampal cortex. Brain slices from neonatal rats will be cultured and studied in the living state using time-lapse laser confocal microscopy. Fluorescent stains and ion indicators will be used to visualize cellular structure and activity patterns. Electrophysiological methods will be used to assess and to manipulate synaptic function. Cells examined physiologically will be reidentified after fixation for immunohistochemical and electron microscopic study. The project will begin with a detailed anatomical, immunohistochemical and electrophysiological baseline study of the in vitro development of three synapses: (1) the excitatory mossy fiber synapse onto pyramidal cells in hippocampal area CA3, (2) the excitatory Schaffer collateral fiber synapse onto pyramidal cells in area CA1, and (3) the inhibitory synapse of basket cells onto pyramidal cells in area CA1. The cultured slice system will then be used to pursue four main questions about the physiology and dynamics of synapse formation: 1. How do axonal growth cones navigate in a cortical tissue environment? 2. How do axonal growth cones and immature dendrites make the initial contact leading to synapse formation? 3. What is the sequence and timing of events between initial contact and establishment of a functional synapse? 4. How does electrical activity influence the formation and stability of synapses? Several specific hypotheses regarding each of these questions will be tested. The proposed studies should provide insights into abnormalities of neural development including birth defects, learning disorders and mental retardation. They may also help to suggest medical procedures for prevention or reversal of neurological deficits associated with trauma and stroke. Finally, they may elucidate the developmental basis for normal aging effects on nervous system function and also for degenerative conditions such as Parkinson's and Alzheimer's diseases.