Brauer K, Werner L, Winkelmann E, Lüth H J
J Hirnforsch. 1981;22(1):59-74.
Morphology of neurons and afferent axons in the dorsal lateral geniculate nucleus (dLGN) of the tree shrew (Tupaia glis) was studied using Golgi-Kopsch impregnated and Nissl stained material. Staining of acetylcholinesterase (AChE) could inform about the distribution of this enzyme in the tree shrew's dLGN. The results can be summarized as follows: 1. Two classes of neurons can be identified: class-I-neurons and class-II-neurons. Class-I-neurons correspond to geniculo-cortical relay neurons (GCR-neurons) and class-II-neurons correspond to local interneurons (I-neurons). 2. Class-I-neurons differ in their morphology depending on their laminar position. Tufted neurons with clusters of grape-like appendages in their branching zones resembling X-cells in the cat's dLGN are localized in the external laminae 5 and 4. In the superficial lamina 6 the dendrite domains of GCR-neurons are flattened and elongated. Dendrites seem not to penetrate laminar borders. The cells in layer 3 have the smallest soma and radiate dendrites. There is some evidence that GCR-neurons in this lamina represent W-cells (Carey et al., 1979). GCR-neurons in laminae 2 and 1 (innermost laminae) have the biggest somata. Their dendritic branching patterns make it difficult to classify the cells into tufted or radiate. Branching zones are rather smooth. These cells seem to be good candidates for Y-cells. 3. I-neurons could be identified in all laminae. Their dendrites preferentially take a dorso-ventral course. Only axon initial segments of these neurons were visible in Golgi preparations. 4. GCR-neurons and I-neurons could also be identified in Nissl preparations. The ratio GCR-neurons: I-neurons is about 10:1, i.e. 10% of all neurons are I-neurons. 5. In Golgi preparations some types of axons were impregnated. Type-1-axons resemble cortical afferents of other mammalian species. Type-2-axons (2a, 2b, 2c) do not leave single laminae in our material. Considering branching characteristics of their terminal zones, this finding could be a reference for their retinal origin. 6. Laminae 5, 4, 2, and 1 have a remarkable higher content of AChe than the laminae 6 and 3. The low level of ACHE in lamina 3 of the tree shrew's dLGN corresponds to the less activity of ACHE in the laminae 4 and 5 of Galago senegalensis (Fitzpatrick and Diamond, 1979), which like lamina 3 in Tupaia's dLGN project to layer I of the visual cortex (Carey et al., 1979).
利用高尔基-科普希浸染法和尼氏染色材料，研究了树鼩（笔尾树鼩）背外侧膝状核（dLGN）中神经元和传入轴突的形态。乙酰胆碱酯酶（AChE）染色可以揭示该酶在树鼩dLGN中的分布情况。结果总结如下：1. 可识别出两类神经元：I类神经元和II类神经元。I类神经元对应膝状体-皮质中继神经元（GCR神经元），II类神经元对应局部中间神经元（I神经元）。2. I类神经元的形态因其所在层位而异。在其分支区域有葡萄状附属物簇的簇状神经元，类似于猫dLGN中的X细胞，位于外侧层5和4。在浅层6中，GCR神经元的树突域扁平且细长。树突似乎不穿透层界。第3层中的细胞胞体最小，有放射状树突。有证据表明该层中的GCR神经元代表W细胞（凯里等人，1979年）。第2层和第1层（最内层）中的GCR神经元胞体最大。它们的树突分支模式难以将细胞归类为簇状或放射状。分支区域相当平滑。这些细胞似乎是Y细胞的良好候选者。3. 在所有层中均可识别出I神经元。它们的树突优先呈背腹走向。在高尔基制剂中仅可见这些神经元的轴突起始段。4. 在尼氏制剂中也可识别出GCR神经元和I神经元。GCR神经元与I神经元的比例约为10:1，即所有神经元中有10%是I神经元。5. 在高尔基制剂中，一些类型的轴突被浸染。1型轴突类似于其他哺乳动物物种的皮质传入纤维。2型轴突（2a、2b、2c）在我们的材料中不离开单个层。考虑到其终末区域的分支特征，这一发现可为其视网膜起源提供参考。6. 第5、4、2和1层的乙酰胆碱酯酶含量明显高于第6和3层。树鼩dLGN第3层中乙酰胆碱酯酶水平较低，这与塞内加尔婴猴第4和5层中乙酰胆碱酯酶活性较低相对应，塞内加尔婴猴的第3层与树鼩dLGN的第3层一样，投射到视觉皮层的第I层（凯里等人，1979年）。
