Walker R H, Arbuthnott G W, Baughman R W, Graybiel A M
Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge 02139.
J Comp Neurol. 1993 Nov 22;337(4):614-28. doi: 10.1002/cne.903370407.
Medium spiny neurons are the projection neurons of the striatum. They receive the majority of striatal afferents, and they make up the vast majority of all neurons in the striatum. These densely spiny cells thus constitute a major substrate for input-output processing in the striatum. In the experiments described here we analyzed the dendritic fields of spiny neurons in the squirrel monkey striatum and plotted their orientations with respect to the borders between striosomes and matrix. Medium-sized spiny neurons in the caudate nucleus were filled intracellularly in a fixed-slice preparation with the fluorescent dye Lucifer Yellow. Dendritic arbors were reconstructed following immunostaining of the injected neurons with antiserum to Lucifer Yellow and counterstaining for striosome/matrix compartments. A majority of the medium spiny neurons studied had dendritic arborizations that remained within their compartment of origin. Thus the striosome/matrix subdivision not only partitions neurotransmitter molecules and extrinsic striatal connections into two domains in the primate caudate nucleus, but also constrains the dendritic arbors of many projection neurons there. Other medium spiny neurons, however, in both striosomes and matrix, had dendrites that crossed from one compartment into the other. About a quarter of the spiny neurons reconstructed had at least one such crossing dendrite. These results suggest that compartmentalization of afferent and efferent processing by projection neurons in the primate striatum is not absolute. For a subpopulation of spiny neurons in striosomes and matrix, inputs to one compartment could have a direct influence on output cells of the other.
中等棘状神经元是纹状体的投射神经元。它们接收纹状体的大部分传入神经，并且构成纹状体内所有神经元的绝大多数。因此，这些密集有棘的细胞构成了纹状体中输入 - 输出处理的主要基质。在本文所述的实验中，我们分析了松鼠猴纹状体中棘状神经元的树突场，并绘制了它们相对于纹状体小体和基质之间边界的方向。在固定切片标本中，用荧光染料路西法黄对尾状核中的中等大小棘状神经元进行细胞内填充。在用抗路西法黄抗血清对注射的神经元进行免疫染色并对纹状体小体/基质区室进行复染后，重建树突分支。所研究的大多数中等棘状神经元的树突分支都保留在其起源的区室内。因此，纹状体小体/基质细分不仅将神经递质分子和纹状体外部连接分隔在灵长类动物尾状核的两个区域中，而且还限制了那里许多投射神经元的树突分支。然而，纹状体小体和基质中的其他中等棘状神经元有从一个区室交叉到另一个区室的树突。重建的棘状神经元中约四分之一至少有一个这样的交叉树突。这些结果表明，灵长类动物纹状体中投射神经元的传入和传出处理的分隔不是绝对的。对于纹状体小体和基质中的一个棘状神经元亚群，一个区室的输入可能对另一个区室的输出细胞有直接影响。
