King J S, Chen Y F, Bishop G A
Department of Cell Biology, Neurobiology and Anatomy, Ohio State University, Columbus 43210.
Anat Embryol (Berl). 1993 Sep;188(3):299-305. doi: 10.1007/BF00188220.
The axons of basket cells course horizontally within the lower molecular layer of the cerebellar cortex and give rise to three types of axon collaterals. One collateral distributes around the somata and axon hillocks of Purkinje cells, forming a complex pericellular basket-like formation or "pinceau". The other two axonal specializations have the form of beaded tendrils, but differ in their origin and laminar distribution. In the previous paper, the morphometry and configuration of these axonal branches were described. In the present account, their synaptic relationships are analyzed based on serial section analysis and computer reconstructions. Our data indicate that: (1) Purkinje cells receive descending collaterals from more than one basket cell; (2) the contribution of the descending collaterals to individual pinceau is not uniform; Purkinje cells located close to the basket cell of origin receive a greater number of descending collaterals when compared to Purkinje cells located more distally; (3) few synaptic junctions are formed by the descending collaterals within the pinceaux; (4) beaded tendrils make synaptic contacts with the somata and dendrites of Purkinje cells, and (5) the horizontal axon forms synaptic junctions with the dendritic shafts and spiny branchlets of Purkinje cells. Functional considerations of these synaptic relationships are discussed in the light of the classic concept of off-beam inhibition mediated by basket cells.
篮状细胞的轴突在小脑皮质的分子层下部水平走行，并发出三种类型的轴突侧支。一种侧支分布在浦肯野细胞的胞体和轴突丘周围，形成复杂的细胞周围篮状结构或“套圈”。另外两种轴突特化形式为串珠状卷须，但它们的起源和层状分布不同。在前一篇论文中，描述了这些轴突分支的形态测量和结构。在本报告中，基于连续切片分析和计算机重建对它们的突触关系进行了分析。我们的数据表明：（1）浦肯野细胞从不止一个篮状细胞接收下行侧支；（2）下行侧支对单个套圈的贡献不均匀；与位于更远端的浦肯野细胞相比，靠近起源篮状细胞的浦肯野细胞接收更多的下行侧支；（3）下行侧支在套圈内形成的突触连接很少；（4）串珠状卷须与浦肯野细胞的胞体和树突形成突触联系，以及（5）水平轴突与浦肯野细胞的树突干和棘状小分支形成突触连接。根据篮状细胞介导的离束抑制的经典概念，讨论了这些突触关系的功能意义。
