Paloff A M, Usunoff K G, Hinova-Palova D V
Department of Anatomy, Histology, Faculty of Medicine, Medical Academy, Sofia, Bulgaria.
J Hirnforsch. 1992;33(4-5):361-407.
The combined Golgi/electron microscope technique was used to analyse the cytoarchitecture and the fine structure of the central nucleus of the inferior colliculus in the cat. The analysis of Golgi-impregnated sections discriminates three major neuronal types, according to somato-dendritic morphology, and to presence or absence of dendritic spines. Two major types (spiny and aspiny) might be further subdivided into large, medium-large, medium-small and small, whilst the third ("mixed") type is subdivided into large and medium-large types. The large, medium-large and medium-small cells of the major types appear to be efferent (relay) neurons, whilst the small spiny, and especially the small aspiny cells are interneurons. In agreement with previous data, the subdivision of the relay neurons in disc-shaped and stellate cells is confirmed but the disc-shaped neurons are further subdivided in typical and atypical. The dendritic fields of the latter neurons correspond greatly but not exclusively to the fibrodendritic laminae of the central nucleus. In addition to the axonal ramification of the local circuit neurons, the axons of most (if not all) types of relay cells emit a moderate to scant, rarely--a substantial number of collaterals. The collaterals of the large spiny neurons (atypical disc-shaped cells) occasionally innervate also the cell of origin. Parallel to the light microscopic discriminations of the different neuronal types, the electron microscopic observations confirm that the ultrastructural characteristics might be very distinct. Especially evident are the differences between the large neuronal types, concerning the amount and arrangement of the granular endoplasmic reticulum, and the mode of the perikaryal, dendritic, and axonal innervation by various synaptic bouton types. Along with the unequivocal discrimination of the neurons in the central nucleus of the inferior colliculus according to the dendritic orientation, we suggest also a more detailed classification of the neuronal types according to the perikaryal size, fine dendritic morphology, and ultrastructural characteristics. Further hodological experiments, combined with the presently explored technique, will help to clarify the complicated synaptic events in the central nucleus of the inferior colliculus.
采用高尔基染色法与电子显微镜技术相结合的方法，对猫下丘中央核的细胞结构和精细结构进行分析。根据细胞体-树突形态以及树突棘的有无，对高尔基染色切片的分析可区分出三种主要神经元类型。两种主要类型（有棘和无棘）可进一步细分为大、中大、中小和小四种，而第三种（“混合”）类型则细分为大、中大两种。主要类型中的大、中大、中小细胞似乎是传出（中继）神经元，而小的有棘细胞，尤其是小的无棘细胞是中间神经元。与先前的数据一致，中继神经元可分为盘状和星状细胞，这一点得到了证实，但盘状神经元进一步细分为典型和非典型。后一种神经元的树突野与中央核的纤维树突层有很大但并非完全对应的关系。除了局部回路神经元的轴突分支外，大多数（如果不是全部）中继细胞类型的轴突发出适度到稀少的侧支，很少有大量侧支。大的有棘神经元（非典型盘状细胞）的侧支偶尔也会支配其起源细胞。与不同神经元类型的光学显微镜鉴别平行，电子显微镜观察证实超微结构特征可能非常不同。大神经元类型之间的差异尤其明显，涉及粗面内质网的数量和排列，以及各种突触小体类型对胞体、树突和轴突的支配方式。除了根据树突方向对下丘中央核的神经元进行明确鉴别外，我们还建议根据胞体大小、精细的树突形态和超微结构特征对神经元类型进行更详细的分类。进一步的追踪实验，结合目前探索的技术，将有助于阐明下丘中央核中复杂的突触事件。
