Phillipson O T
J Comp Neurol. 1979 Sep 1;187(1):99-115. doi: 10.1002/cne.901870107.
The ventral tegmental area of Tsai (VTA) and interfascicular nucleus of the adult rat brain has been studied with two variants of the Golgi method in three planes of section. Neurons were studied in relation to the cytoarchitectural groupings of the VTA. Dendritic organisation and dendritic fields were mapped out for each cytoarchitectural subgroup and cell types within each subgroup were classified on the basis of cell size and dendritic morphology. In each subnucleus of VTA, neurons had distinct characteristics. In nucleus paranigralis neurons were small to medium in size and their dendritic fields organised in an approximately horizontal plane orientated in an anteromedial direction and slanting dorsally over the interpeduncular nucleus and fossa. Neurons of the parabrachial group were small to medium sized with no preferential orientation. In nucleus linearis raphe caudalis small neurons were strongly orientated in the plane of the nucleus in a dorso-ventral direction slanting forwards. Neurons in the interfascicular group were small to very small and their maximum dendritic extents were seen in the horizontal plane. In frontal section they formed a compact ball of cells in the midline and were separated on either side from the larger neurons in the medial edge of nucleus paranigralis. In general VTA neurons tended to fall into one of two morphological categories. Type 1 were small to medium, and had two to four primary dendrites which divided into varicose secondary dendrites. Type 2 were medium sized, with two to five primary dendrites. Both primary and secondary dendrites and the cell soma of Type 2 neurons were moderately spiny. Secondary dendrites were not varicose. Forms also occurred which were intermediate between Types 1 and 2. In the nucleus paranigralis, Type 1 was more common medially, while Type 2 was more common laterally, particularly in the ventrolateral paranigral region. Only neurons of Type 1 were seen in nucleus linearis raphe and interfascicular nuclei. Local axon circuits were observed to arise from the primary dendrites of Type 1 neurons and to ramify close to neighbouring neurons. Axon swellings from such circuits were observed to make apparent contact with primary dendrites of nearby neurons and clusters of axon swellings were observed near cell somas of neighbouring impregnated neurons of similar type. The results are discussed and particular attention is paid to the similarities and differences between VTA and the substantia nigra pars compacts (SNC). The major difference appears to be that, whereas in SNC dendrites are organised in vertical as well as horizontal planes, in the VTA no long ventrally directed dendrites were observed. Combining these results with known cytoarchitecture and connections of VTA and SNC, it appears that fundamental differences occur between VTA and some neurons of the SNC, both in the nature of their morphology and intrinsic organisation, and in the organisation of their efferent and afferent connections.
采用两种高尔基染色法的变体，在三个切片平面上对成年大鼠脑的蔡氏腹侧被盖区（VTA）和束间核进行了研究。结合VTA的细胞构筑分组对神经元进行了研究。绘制了每个细胞构筑亚组的树突组织和树突场，并根据细胞大小和树突形态对每个亚组内的细胞类型进行了分类。在VTA的每个亚核中，神经元都有明显的特征。在黑质旁核中，神经元大小从中等到小，其树突场在一个大致水平的平面内组织，该平面朝前内侧方向，在脚间核和脚间窝上方背侧倾斜。臂旁核组的神经元大小从中等到小，无优先取向。在中缝线性核尾侧，小神经元在核平面内强烈地沿背腹方向向前倾斜。束间核组的神经元大小从非常小到小，其最大树突范围见于水平平面。在额状切面上，它们在中线形成一个紧密的细胞团，并在两侧与黑质旁核内侧边缘的较大神经元分开。一般来说，VTA神经元倾向于分为两种形态类别之一。1型神经元大小从中等到小，有两到四条初级树突，这些初级树突再分为曲张的次级树突。2型神经元大小中等，有两到五条初级树突。2型神经元的初级和次级树突以及细胞体都有适度的棘突。次级树突不是曲张的。也出现了介于1型和2型之间的形态。在黑质旁核中，1型神经元在内侧更常见，而2型神经元在外侧更常见，特别是在腹外侧黑质旁区域。在中缝线性核和束间核中只观察到1型神经元。观察到局部轴突回路起源于1型神经元的初级树突，并在邻近神经元附近分支。观察到来自这些回路的轴突膨体与附近神经元的初级树突明显接触，并且在邻近的同类浸渍神经元的细胞体附近观察到轴突膨体簇。对结果进行了讨论，并特别关注了VTA与黑质致密部（SNC）之间的异同。主要差异似乎在于，在SNC中，树突在垂直和水平平面内都有组织，而在VTA中未观察到长的腹侧树突。将这些结果与已知的VTA和SNC的细胞构筑及连接相结合，似乎VTA与SNC的一些神经元在形态和内在组织的性质以及传出和传入连接的组织方面都存在根本差异。
