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神经连接的形成. 神经元的发育: 外胚层细胞形成神经元,神经嵴或者表皮 什么类型的神经元 神经元的靶细胞. 外胚层. BMP (-). 神经管. Notch/Delta. 神经元. Shh. 运动神经元. hox. Hox and Lim. 神经元连接聚焦到两个主要的系统: 运动神经元 —— 其轴突从脊髓出发到达特定的肌肉 视觉系统 —— 轴突从视网膜出发到达脑.
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神经元的发育: • 外胚层细胞形成神经元,神经嵴或者表皮 • 什么类型的神经元 • 神经元的靶细胞
外胚层 BMP(-) 神经管 Notch/Delta 神经元 Shh 运动神经元
神经元连接聚焦到两个主要的系统: • 运动神经元——其轴突从脊髓出发到达特定的肌肉 • 视觉系统——轴突从视网膜出发到达脑
1. Pathway selection, wherein the axons travel along a route that leads them to a particular region of the embryo • 2. Target selection, wherein the axons, once they reach the correct area, recognize and bind to a set of cells with which they may form stable connections • 3. Address selection, wherein the initial patterns are refined such that each axon binds to a small subset (sometimes only one) of its possible targets
Pathway selection Cell adhesion and contact guidance by attractive and permissive molecules 轴突生长锥最初的路径是由其细胞外的环境决定的。
Guidance by specific growth cone repulsion ephrins and semaphorins ephrins
Guidance by diffusible molecules 1 Neterin and their receptors 联合神经元是一种中间 神经元
dorsal spinal cord explants. Transformed chick fibroblast (COS) cells secreting netrins elicit axon outgrowth of commissural neurons from 11 -day embryonic rat dorsal spinal cord explants.
2 Slit AND Robo In Drosophila, Slit is secreted by the neuralcells in the midline; growth cones of Drosophila neurons express a Roundabout (Robo)
Target selection sensory neurons from the rat dorsal root ganglia& NT3 Neurotrophins: nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophins 3 and 4/5 (NT3, NT4/5).
"address selection" competition
Differential survival after innervation:Neurotrophic factors
总结 神经突起的发育 轴突和树突的生长 发育期间突触连接形成 突触连接的重排及精细化