Wright C I, Groenewegen H J
Graduate School in Neurosciences Amsterdam, Department of Anatomy and Embryology, Vrije Universiteit, The Netherlands.
J Comp Neurol. 1995 Oct 23;361(3):383-403. doi: 10.1002/cne.903610304.
In the rat, fibers from the prelimbic cortex terminate in the medial nucleus accumbens. Anterior paraventricular thalamic and parvicellular basal amygdaloid fibers reached both the prelimbic cortex and the medial nucleus accumbens. All three afferent systems have an inhomogenous distribution within the nucleus accumbens, and whether or not these projections actually reach the same areas is unknown. Our aim was to evaluate the relationships of the three afferents with respect to the shell, the core, and the cell clusters of the nucleus accumbens. Double anterograde tracing and single anterograde tracing combined with immunohistochemistry for calbindin (D28k) or Nissl stain was used. Following tracer injections in the prelimbic cortex and the anterior paraventricular thalamus, a complementary (i.e., nonoverlapping) pattern of fibers was found in the shell. Thus, afferents from the prelimbic cortex are associated with cell clusters, whereas those from the anterior paraventricular thalamus avoid these cells but are affiliated with regions exhibiting weak homogeneous calbindin immunoreactivity. In the calbindin-poor patches of the core, the situation is reversed as both sets of fibers overlap. In cases with injections in the prelimbic cortex and the parvicellular basal amygdala, a pattern of overlap was seen in the shell and core. Thus, the fibers in the shell were found together in association with cell clusters, whereas regions of weak homogeneous calbindin immunoreactivity were avoided. In the core, overlap was seen in the patch compartment. Finally, with parvicellular basal amygdala/paraventricular thalamus injections, a complementary fiber organization was present in the shell, but overlap was prominent in the patches of the core. The results demonstrate that the relationships of prelimbic cortical, paraventricular thalamic, and parvicellular basal amygdaloid afferents in the nucleus accumbens vary according to their compartmental (immunohistochemical and cellular) affiliation. Compartmentalization is therefore a possible anatomical substrate for condensation or segregation of neuronal signals passing through the nucleus accumbens.
在大鼠中，来自前边缘皮层的纤维终止于伏隔核内侧。丘脑室旁前部和杏仁核基底小细胞的纤维同时到达前边缘皮层和伏隔核内侧。所有这三种传入系统在伏隔核内的分布都不均匀，而且这些投射是否实际到达相同区域尚不清楚。我们的目的是评估这三种传入纤维与伏隔核壳、核心及细胞簇之间的关系。采用了双顺行示踪以及将单顺行示踪与钙结合蛋白（D28k）免疫组化或尼氏染色相结合的方法。在前边缘皮层和丘脑室旁前部注射示踪剂后，在壳区发现了互补（即不重叠）的纤维模式。因此，来自前边缘皮层的传入纤维与细胞簇相关，而来自丘脑室旁前部的传入纤维避开这些细胞，但与显示弱均匀钙结合蛋白免疫反应性的区域相关。在核心区钙结合蛋白含量低的区域，情况则相反，两组纤维重叠。在前边缘皮层和杏仁核基底小细胞注射的情况下，在壳区和核心区都观察到重叠模式。因此，壳区的纤维共同与细胞簇相关，而避开了弱均匀钙结合蛋白免疫反应性的区域。在核心区，在小块区域观察到重叠。最后，在杏仁核基底小细胞/丘脑室旁注射时，壳区存在互补的纤维组织，但在核心区的小块区域重叠明显。结果表明，伏隔核中前边缘皮层、丘脑室旁和杏仁核基底小细胞传入纤维之间的关系根据它们的分区（免疫组化和细胞）归属而有所不同。因此，分区可能是通过伏隔核的神经元信号凝聚或分离的一种解剖学基础。
