ANATOMICAL ANALYSIS OF NEURONAL CIRCUITS

这个项目旨在提高我们对详细电路的理解 丘脑及其与觉醒、睡眠-觉醒周期的关系，以及 信息从皮质下中继器传递到大脑皮层。在……里面 这个项目之前的工作，光显微分析 去甲肾上腺素(NA)传入丘脑网状核(TRN)显示 来自中等密度的轴突网络的神经轴突 在这个丘脑核内。鼻轴突看起来是随机的 分布于TRN内，多巴胺-β-羟基酶阳性 (DBH+)近端和远端树突上均可见轴突 TRN神经元的突起，较少出现在体细胞上。今年, 胸径加工的TRN神经细胞的电子显微镜观察 免疫组织化学显示DBH+轴突使非典型性 ALL与网状神经元树突的非对称性突触接触 直径。这些观察表明，蓝斑NA系统，在 除了影响背侧丘脑和大脑皮层 直接，可以通过其投影间接影响信号流 对TRN神经元的影响。 该项目还包括对γ-氨基丁酸的分析。 丘脑中含有(GABA能)系统的。丘脑的一个模型 门控机制提出了TRN终末在 大脑皮层主干中继神经元和GABA能局部环路神经元 不同行为状态下的背侧丘脑。大部分工作 该模型的基础是猫，但对丘脑的研究 在体外的功能经常依赖于啮齿动物的制剂，如 豚鼠切片。因为里面几乎没有GABA能神经元 许多大鼠和小鼠的中继核，该模型在 它对豚鼠等啮齿动物的适用性。因此， 本实验观察了豚鼠丘脑背侧LCNs的分布。 免疫组织化学技术。GABA能神经元分布更广 在豚鼠丘脑内，而不是在大鼠和小鼠的丘脑中， 在豚鼠体内发现了不同的GABA神经元群 腹基复合体，在大鼠和小鼠中不存在。因此，有 LCNs在不同啮齿动物中的分布差异很大 物种，这一发现与丘脑门控模型有关。

This project seeks to improve our understanding of the detailed circuitry of the thalamus and its relation to arousal, sleep-wakefulness cycles, and information transfer from subcortical relays to the cerebral cortex. In previous work on this project, light microscopic analysis of the noradrenergic (NA) input to the thalamic reticular nucleus (TRN) showed that the NA axons from a moderately dense meshwork of boutons en passant within this thalamic nucleus. The NA axons are seemingly randomly distributed within the TRN, with the dopamine-beta-hydroxylase positive (DBH+) axons appearing to about upon both proximal and distal dendritic processes of TRN neurons, and less frequently, upon somata. This year, electron microscopic examination of TRN neurophil processed for DBH immunohistochemistry indicated that DBH+ axonal boutons make atypical asymmetric synaptic contacts with reticular neuron dendrites of all diameters. These observations show that the locus coeruleus NA system, in addition to influencing the dorsal thalamus and the cerebral cortex directly, can influence the signal flow indirectly through its projection upon TRN neurons. This project also involves an analysis of gamma-aminobutyric acid containing (GABAergic) systems in the thalamus. One model of thalamic gating mechanisms proposes a differential role of TRN terminals upon the principal relay neurons and the GABAergic local circuit neurons (LCNs) of the dorsal thalamus during different behavioral states. Much of the work upon which the model is based involves cats, but studies of thalamic function in vitro have frequently relied upon rodent preparations, such as guinea pig slices. Since there are virtually no GABAergic neurons within many relay nuclei of rats and mice, the model could be questioned in terms of its applicability to rodents such as guinea pigs. Accordingly, the distribution of dorsal thalamic LCNs was examined in guinea pigs, with immunohistochemical techniques. GABAergic neurons are more widespread within guinea pig thalamus than in the thalami of rats and mice, and a distinct population of GABA neurons is found within the guinea pig ventrobasal complex, which is not found in rats and mice. Thus, there is considerable variation in the distribution of LCNs among different rodent species, a finding which is of relevance to models of thalamic gating.