ANATOMICAL ANALYSIS OF NEURONAL CIRCUITS

丘脑网状核的结构组织为 通过注射荧光染料路西法黄进行研究， 在固定的组织切片中细胞内分化为已鉴定的神经元 老鼠的大脑。此方法提供了有关 网状核神经元的树突几何结构，特别是 对于探索选定区域的微电路非常有用 大脑，因为它可以与其他 神经解剖学技术。在成功地建立了 这项工作的设施，单个神经元的结构 对丘脑网状核进行了仔细的检查和 有记录在案。丘脑网状核的传入传入 已经使用顺行和逆行轴突进行了研究 光纤跟踪技术。除了众所周知的输入之外 来自丘脑和丘脑的主要神经元的侧支 大脑皮层VI层的皮质丘脑神经元， 网状核的一般区域也接受来自 几个胆碱能细胞群。这些包括臂旁核 核、桥小脚核和巨细胞 基底核。顺行示踪剂注入脑内 臂旁核或桥脚核标记轴突 紧密相邻的Incerta地带内的乔木，但不贴标签 位于网状核内的神经元。相比之下，示踪剂注射 进入基底核导致了大量的 轴突末梢乔木组织分散，分布广泛 丘脑网状核。这些发现表明， 丘脑网状核可能在胆碱能中起关键作用 调节大脑皮层的输入。

The structural organization of the thalamic reticular nucleus was investigated by injecting the fluorescent dye, Lucifer yellow, intracellularly into identified neurons in fixed of tissue slices of the rat brain. This method provides a complete picture of the dendritic geometry of reticular nucleus neurons and is particularly useful for exploring the microcircuitry of selected regions of the brain, since it can be used in conjunction with other neuroanatomical techniques. Having successfully established the facilities for this work, the structure of individual neurons in the thalamic reticular nucleus has been carefully examined and documented. The afferent input to the thalamic reticular nucleus has than been studied using both anterograde and retrograde axonal fiber tracing techniques. In addition to the well known inputs from collaterals of principal neurons in the thalamus and corticothalamic neurons in layer VI of the cerebral cortex, the general region of the reticular nucleus also receives inputs from several cholinergic cell groups. These include the parabrachial nucleus, the pedunculopontine nucleus, and the magnocellular nucleus basalis. Anterograde tracer injections into the parabrachial nucleus or the pedunculopontine nucleus label axonal arbors within the closely adjacent zona incerta, but do not label those within the reticular nucleus. In contrast, tracer injections into the nucleus basalis result in a significant amount of diffusely organized and widespread axonal terminal arbors within the thalamic reticular nucleus. These findings suggest that the thalamic reticular nucleus may be pivotal in the cholinergic modulation of inputs to the cerebral cortex.