Giménez-Amaya J M, Graybiel A M
Departamento de Morfología, Facultad de Medicina, Universidad Autónoma de Madrid, Spain.
J Neurosci. 1991 Mar;11(3):779-91. doi: 10.1523/JNEUROSCI.11-03-00779.1991.
It is well known that the striatum has a chemical architecture dividing it into striosomes and matrix, and that these compartments have different input-output connections. However, striatal afferent-fiber systems also form vividly patchy terminal fields in the matrix, and studies in the past year have uncovered instances of nonstriosomal clustering of striatal output neurons. In the experiments reported here, we systematically investigated this output-neuron clustering in the primate, using the striatopallidal system as a model. Our goals were to determine whether the modular organization is a general characteristic of projection neurons in the striatal matrix, whether the modularity occurs independent of striosomal boundaries, and whether the output modules are systematically organized. We studied the distribution of striatopallidal projection neurons in 9 adult squirrel monkeys by centering deposits of the retrograde tracer HRP-WGA in either the external segment or the internal segment of the globus pallidus. Following injections of each type, many retrogradely labeled neurons appeared in the striatal matrix in clusters and bands having cross-sectional diameters of 0.2-0.8 mm. Comparisons with adjoining sections stained to demonstrate striosomes established that the local groups of striatal output neurons sometimes abutted striosomes but often did not. The retrogradely labeled clusters and bands appeared both in the caudate nucleus and in the putamen. Their arrangements were regular and often periodic. These findings suggest that the large matrix compartment of the primate striatum, which is the primary site of origin of striatal outputs to the pallidum and the reticular part of the substantia nigra, contains systematic mosaics of projection neurons. We propose that this output-neuron modularity of the striatal matrix in the primate could serve as the template for redistribution of the massive afferent-fiber systems of the striatum into specialized striatopallidal output channels.
众所周知，纹状体具有化学结构，可将其分为纹状小体和基质，并且这些分区具有不同的输入 - 输出连接。然而，纹状体传入纤维系统在基质中也形成了明显的斑块状终末场，并且过去一年的研究发现了纹状体输出神经元的非纹状小体聚集的实例。在本文报道的实验中，我们以纹状体苍白球系统为模型，系统地研究了灵长类动物中的这种输出神经元聚集。我们的目标是确定模块化组织是否是纹状体基质中投射神经元的一般特征，模块化是否独立于纹状小体边界发生，以及输出模块是否有系统地组织。我们通过将逆行示踪剂HRP - WGA注射到苍白球的外侧段或内侧段，研究了9只成年松鼠猴中纹状体苍白球投射神经元的分布。在每种类型的注射后，许多逆行标记的神经元出现在纹状体基质中，呈簇状和带状，横截面直径为0.2 - 0.8毫米。与染色以显示纹状小体的相邻切片进行比较表明，纹状体输出神经元的局部群体有时与纹状小体相邻，但通常不相邻。逆行标记的簇和带出现在尾状核和壳核中。它们的排列是规则的，并且常常是周期性的。这些发现表明，灵长类动物纹状体的大基质区是纹状体向苍白球和黑质网状部输出的主要起源部位，包含投射神经元的系统镶嵌。我们提出，灵长类动物纹状体基质中的这种输出神经元模块化可以作为纹状体大量传入纤维系统重新分布到专门的纹状体苍白球输出通道的模板。
