Laboratorio de Neuromorfología Funcional, Clínica Universitaria de Navarra, Pamplona, Spain.
PLoS One. 2012;7(1):e30504. doi: 10.1371/journal.pone.0030504. Epub 2012 Jan 17.
The afferent projections of the striatum (caudate nucleus and putamen) are segregated in three territories: associative, sensorimotor and limbic. Striatal interneurons are in part responsible for the integration of these different types of information. Among them, GABAergic interneurons are the most abundant, and can be sorted in three populations according to their content in the calcium binding proteins calretinin (CR), parvalbumin (PV) and calbindin (CB). Conversely, striatal dopaminergic cells (whose role as interneurons is still unclear) are scarce. This study aims to analyze the interneuron distribution in the striatal functional territories, as well as their organization regarding to the striosomal compartment.
METHODOLOGY/PRINCIPAL FINDINGS: We used immunohistochemical methods to visualize CR, PV, CB and tyrosine hydroxylase (TH) positive striatal neurons. The interneuronal distribution was assessed by stereological methods applied to every striatal functional territory. Considering the four cell groups altogether, their density was higher in the associative (2120±91 cells/mm(3)) than in the sensorimotor (959±47 cells/mm(3)) or limbic (633±119 cells/mm(3)) territories. CB- and TH-immunoreactive(-ir) cells were distributed rather homogeneously in the three striatal territories. However, the density of CR and PV interneurons were more abundant in the associative and sensorimotor striatum, respectively. Regarding to their compartmental organization, CR-ir interneurons were frequently found in the border between compartments in the associative and sensorimotor territories, and CB-ir interneurons abounded at the striosome/matrix border in the sensorimotor domain.
CONCLUSIONS/SIGNIFICANCE: The present study demonstrates that the architecture of the human striatum in terms of its interneuron composition varies in its three functional territories. Furthermore, our data highlight the importance of CR-ir striatal interneurons in the integration of associative information, and the selective role of PV-ir interneurons in the motor territory. On the other hand, the low density of dopaminergic cells casts doubts about their role in the normal human striatum.
纹状体（尾状核和壳核）的传入投射分为三个区域：联合区、感觉运动区和边缘区。纹状体中间神经元部分负责整合这些不同类型的信息。其中，GABA 能中间神经元最为丰富，根据其钙结合蛋白 calretinin（CR）、parvalbumin（PV）和 calbindin（CB）的含量可分为三种。相反，纹状体多巴胺能细胞（其作为中间神经元的作用仍不清楚）较少。本研究旨在分析纹状体功能区的中间神经元分布及其与纹状体隔室的组织关系。
方法/主要发现：我们使用免疫组织化学方法可视化 CR、PV、CB 和酪氨酸羟化酶（TH）阳性纹状体神经元。通过立体学方法评估每个纹状体功能区的中间神经元分布。综合考虑这四种细胞群，它们在联合区（2120±91 个细胞/mm³）的密度高于感觉运动区（959±47 个细胞/mm³）和边缘区（633±119 个细胞/mm³）。CB 和 TH 免疫反应（ir）细胞在三个纹状体区域的分布较为均匀。然而，CR 和 PV 中间神经元的密度在联合区和感觉运动区分别更为丰富。关于它们的隔室组织，CR-ir 中间神经元在联合区和感觉运动区的隔室边界处经常被发现，而 CB-ir 中间神经元在感觉运动区的纹状体/基质边界处丰富。
结论/意义：本研究表明，人类纹状体在其三个功能区的中间神经元组成方面存在结构差异。此外，我们的数据突出了 CR-ir 纹状体中间神经元在整合联合信息方面的重要性，以及 PV-ir 中间神经元在运动区的选择性作用。另一方面，多巴胺能细胞的低密度使人对其在正常人类纹状体中的作用产生怀疑。
