Wright C I, Groenewegen H J
Graduate School Neurosciences Amsterdam, Department of Anatomy and Embryology, Vrije Universiteit, The Netherlands.
Neuroscience. 1996 Jul;73(2):359-73. doi: 10.1016/0306-4522(95)00592-7.
Regions of the prefrontal cortex that project to the nucleus accumbens in the rat receive input from midline thalamic and basal amygdaloid nuclei which also project to the same striatal region as their prefrontal cortical target. For example, the prelimbic cortex projects to the medial nucleus accumbens, and receives input from the paraventricular thalamic nucleus and the parvicellular basal amygdala. These latter two areas also project to the medial nucleus accumbens. It has been shown that afferents from the prelimbic cortex, the paraventricular thalamic nucleus and the parvicellular basal amygdala to the nucleus accumbens overlap or are separated in the nucleus accumbens, depending upon their position in the shell and core. The dorsal agranular insular cortex, the intermediodorsal thalamic nucleus and the magnocellular basal amygdaloid nucleus terminate in the lateral part of the nucleus accumbens and adjacent ventral part of the caudate-putamen. The intermediodorsal thalamic nucleus and the magnocellular basal amygdaloid nucleus reach both the dorsal agranular insular cortex and the lateral nucleus accumbens, and thus appear positioned to influence the prefrontal corticostriatal system at cortical and striatal levels. However, all three afferent systems have a heterogeneous distribution within this striatal region, and whether these projections actually reach the same areas is unknown. We investigated the patterns of separation and overlap in the nucleus accumbens between dorsal agranular insular cortical, magnocellular basal amygdaloid and intermediodorsal thalamic afferents with respect to the histochemical features of the nucleus. Techniques allowing the detection of two different anterograde tracers, or a single anterograde tracer and Calbindin-D28k immunoreactivity, in the same tissue sections were used. The results demonstrate that the afferents from the dorsal agranular insular area and the intermediodorsal thalamic nucleus avoid the shell of the lateral nucleus accumbens, which receives strong inputs from the magnocellular basal amygdala. In the matrix of the core and the ventral part of the caudate-putamen, fibers from the superficial layers of the dorsal agranular insular area overlap precisely with afferents from the intermediodorsal nucleus. In the patches, projections from the deep layers of the dorsal agranular insular cortex coincide with those from the magnocellular basal amygdala. The present findings have implications for the compartmental structure of the nucleus accumbens and provide novel insights into the organizational principles of prefrontal corticostriatal circuits.
大鼠前额叶皮质中投射至伏隔核的区域，接收来自中线丘脑核和基底杏仁核的输入，而这些丘脑核和基底杏仁核也投射至与它们在前额叶皮质的靶区相同的纹状体区域。例如，前边缘皮质投射至伏隔核内侧，且接收来自室旁丘脑核和小细胞基底杏仁核的输入。后两个区域也投射至伏隔核内侧。研究表明，从前边缘皮质、室旁丘脑核和小细胞基底杏仁核至伏隔核的传入纤维，在伏隔核中会重叠或分离，这取决于它们在壳和核中的位置。背侧无颗粒岛叶皮质、丘脑背内侧核和大细胞基底杏仁核终止于伏隔核外侧部分以及尾壳核相邻的腹侧部分。丘脑背内侧核和大细胞基底杏仁核既投射至背侧无颗粒岛叶皮质，也投射至伏隔核外侧，因此似乎能够在皮质和纹状体水平影响前额叶皮质-纹状体系统。然而，所有这三个传入系统在这个纹状体区域内的分布都是不均匀的，而且这些投射是否真的到达相同区域尚不清楚。我们研究了背侧无颗粒岛叶皮质、大细胞基底杏仁核和丘脑背内侧核的传入纤维在伏隔核内相对于伏隔核组织化学特征的分离和重叠模式。我们使用了能够在同一组织切片中检测两种不同顺行示踪剂，或一种顺行示踪剂和钙结合蛋白-D28k免疫反应性的技术。结果表明，来自背侧无颗粒岛叶区域和丘脑背内侧核的传入纤维避开了伏隔核外侧的壳，而壳接收来自大细胞基底杏仁核的大量输入。在核心基质和尾壳核腹侧部分，来自背侧无颗粒岛叶区域浅层的纤维与来自丘脑背内侧核的传入纤维精确重叠。在纹斑中，来自背侧无颗粒岛叶皮质深层的投射与来自大细胞基底杏仁核的投射重合。目前的研究结果对伏隔核的分区结构具有启示意义，并为前额叶皮质-纹状体回路的组织原则提供了新的见解。
