BRAINSTEM PROJECTIONS TO CEREBRUM AND CEREBELLUM

这里提出的实验将确定和比较组织 来自中脑中缝核团的发散轴突投射， 蓝斑和三叉神经核。最近发展起来的，敏感的 将使用双重逆行轴突追踪技术 小麦胚芽凝集素(WGA)、N-[乙酰-3 H]和WGA结合示踪剂 辣根过氧化物酶(HRP)和荧光示踪剂配对 这些脑干神经元投射靶区内的注射策略 揭示其侧支轴突和未分支轴突的顺序 投射。组织的光和荧光显微分析 这些研究中的部分将确定不同之处或相似之处 存在于发散的轴突投射的组织中 脑干单胺能神经元与感觉传递神经元的比较 中脑和三叉神经延髓核神经元。初步 实验表明，接受中脑中缝的每个中枢神经系统结构 投影在地形上具有自己独特的表示形式 中缝的不同部分。似乎中缝神经支配的 具有相互关联的结构通过以下方式相互关联 一组地形截然不同的经络投射 神经元。Small相关顺行轴突示踪实验 在中缝、蓝斑等部位注射凝集素 三叉神经核将显示不同的地形图 这些目标结构的组织和几何有序性 不同方向投射的脑干神经元。蓝斑、中缝和 三叉神经细胞都投射到前脑(如丘脑和 大脑皮质)、中脑(如顶盖和中脑网状结构 后脑(如小脑)和脊椎部位。研究 在此提出，试图解决组织的不同计划 脑干神经元及其向各种中枢神经的轴突投射 系统结构将揭示脑干神经元 大脑和大脑等结构中相互关联的神经元电路 小脑皮质。当这些电路被改变时，通常是一个 神经元丧失的后果，中枢神经系统疾病状态，如 帕金森氏症或脑瘫可能会随之而来。了解 脑干靶标的研制、维护及相关方案 电路将阐明这种情况的原因和可能的治疗方法 疾病。

The experiments proposed here will determine and compare the organization of divergent axonal projections which arise from the midbrain raphe nuclei, locus coeruleus, and trigeminal nuclei. Recently developed, sensitive double retrograde axonal tracing techniques will be employed using the tracers wheat germ agglutinin (WGA), N-[acetyl-3H] and WGA conjugated to horseradish peroxidase (HRP) as well as fluorescent tracers in paired injection strategies within projection targets of these brainstem neuronal groups to reveal the order of their collateralized and unbranched axonal projections. Light and fluorescence microscopic analysis of tissue sections from these studies will determine differences or similarities that exist in the organization of divergent axonal projections arising from brainstem monoaminergic neurons versus those which arise from sensory relay neurons of the midbrain and medullary trigeminal nuclei. Preliminary experiments have revealed that each CNS structure receiving midbrain raphe projections has its own unique representation within a topographically distinct portion of the raphe. It also appears that raphe-innervated structures possessing interconnections with each other are interrelated by a topographically distinct group of collaterilized raphe projection neurons. Correlative anterograde axonal tracing experiments using small injections of lectins within portions of the raphe, locus coeruleus, and trigeminal nuclei will reveal different patterns of topographical organization and geometric orderliness within target structures of these divergently projecting brainstem neurons. Locus coeruleus, raphe, and trigeminal neurons all project to the forebrain (e.g., thalamus and cerebral cortex), midbrain (e.g., tectum and mesencephalic reticular formation), hindbrain (e.g., cerebellum) and spinal sites. Studies proposed here which attempt to resolve the different plans for organizing brainstem neurons and their axonal projections to various central nervous system structures will reveal the ways in which brainstem neurons interrelate neuronal circuitries in such structures as the cerebral and cerebellar cortices. When these circuits are altered, usually a consequence of neuronal loss, central nervous system disease states such as Parkinson's Disease or Cerebral Palsy can follow. Understanding the development, maintenance, and interrelative schemes of brainstem-target circuitries will shed light on the cause and possible treatments for such diseases.