Walker R H, Graybiel A M
Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge 02139.
J Comp Neurol. 1993 Nov 22;337(4):629-39. doi: 10.1002/cne.903370408.
Despite the relatively unfeatured cytoarchitecture of the striatum, this large subcortical region has been found to have a modular macroscopic substructure comprising the neurochemically distinct striosomes and matrix, and, within the matrix, patchy input and output arrangements called matrisomes. In the study reported here, we explored the possibility that the cellular architecture of the striatum is also more specialized than previously suspected. We injected medium spiny neurons in lightly fixed slices of the squirrel monkey caudate nucleus, reconstructed their dendritic arbors, and analyzed the orientations of these arbors with respect to the cardinal planes of the striatum. The data were unequivocal in suggesting that many spiny neurons, whether near striosomes or not, have dendritic arbors with preferred orientations along a diagonal axis running from rostral, dorsal, and medial to caudal, ventral, and lateral. This axis corresponds to the orientations of many striosomes and matrisomes in the squirrel monkey's caudate nucleus. We therefore suggest that the primate striatum is characterized not only by a macroscopic organization dividing it into striosomes and matrisomes, but also by a microscopic architecture observed by the dendritic arbors of many of its projection neurons. We obtained comparable supplementary observations for the ferret caudate nucleus, suggesting that such spatial alignment of spiny dendritic arbors may be a general feature of striatal organization. These polarized dendritic arrangements could provide a cellular framework for compartmental input-output processing within the striatum.
尽管纹状体的细胞结构相对缺乏特征，但这个大的皮质下区域已被发现具有模块化的宏观亚结构，包括神经化学上不同的纹状体小体和基质，并且在基质内，有称为基质小体的斑片状输入和输出排列。在本文报道的研究中，我们探讨了纹状体的细胞结构也比以前怀疑的更具特异性的可能性。我们在松鼠猴尾状核的轻度固定切片中注射中等棘状神经元，重建它们的树突分支，并分析这些分支相对于纹状体基本平面的方向。数据明确表明，许多棘状神经元，无论是否靠近纹状体小体，其树突分支都具有沿着从吻侧、背侧和内侧到尾侧、腹侧和外侧的对角线轴的优先方向。这个轴与松鼠猴尾状核中许多纹状体小体和基质小体的方向相对应。因此，我们认为灵长类纹状体的特征不仅在于将其分为纹状体小体和基质小体的宏观组织，还在于其许多投射神经元的树突分支所观察到的微观结构。我们对雪貂尾状核获得了类似的补充观察结果，表明这种棘状树突分支的空间排列可能是纹状体组织的一个普遍特征。这些极化的树突排列可以为纹状体内的分区输入 - 输出处理提供细胞框架。
