Vertes Robert P, Hoover Walter B
Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, Florida 33431, USA.
J Comp Neurol. 2008 May 10;508(2):212-37. doi: 10.1002/cne.21679.
The paraventricular (PV) and paratenial (PT) nuclei are prominent cell groups of the midline thalamus. To our knowledge, only a single early report has examined PV projections and no previous study has comprehensively analyzed PT projections. By using the anterograde anatomical tracer, Phaseolus vulgaris leucoagglutinin, and the retrograde tracer, FluoroGold, we examined the efferent projections of PV and PT. We showed that the output of PV is virtually directed to a discrete set of limbic forebrain structures, including 'limbic' regions of the cortex. These include the infralimbic, prelimbic, dorsal agranular insular, and entorhinal cortices, the ventral subiculum of the hippocampus, dorsal tenia tecta, claustrum, lateral septum, dorsal striatum, nucleus accumbens (core and shell), olfactory tubercle, bed nucleus of stria terminalis (BST), medial, central, cortical, and basal nuclei of amygdala, and the suprachiasmatic, arcuate, and dorsomedial nuclei of the hypothalamus. The posterior PV distributes more heavily than the anterior PV to the dorsal striatum and to the central and basal nuclei of amygdala. PT projections significantly overlap with those of PV, with some important differences. PT distributes less heavily than PV to BST and to the amygdala, but much more densely to the medial prefrontal and entorhinal cortices and to the ventral subiculum of hippocampus. As described herein, PV/PT receive a vast array of afferents from the brainstem, hypothalamus, and limbic forebrain, related to arousal and attentive states of the animal, and would appear to channel that information to structures of the limbic forebrain in the selection of appropriate responses to changing environmental conditions. Depending on the specific complement of emotionally associated information reaching PV/PT at any one time, PV/PT would appear positioned, by actions on the limbic forebrain, to direct behavior toward a particular outcome over a range of outcomes.
室旁核（PV）和丘脑带核（PT）是中线丘脑的重要细胞群。据我们所知，仅有一篇早期报告研究了PV的投射，且此前没有研究对PT的投射进行过全面分析。通过使用顺行性解剖示踪剂菜豆白细胞凝集素和逆行性示踪剂荧光金，我们研究了PV和PT的传出投射。我们发现，PV的输出实际上指向一组离散的边缘前脑结构，包括皮质的“边缘”区域。这些区域包括内嗅下皮质、内嗅前皮质、背侧无颗粒岛叶皮质和内嗅皮质、海马腹侧下托、背侧带纹、屏状核、外侧隔核、背侧纹状体、伏隔核（核心区和壳区）、嗅结节、终纹床核（BST）、杏仁核的内侧核、中央核、皮质核和基底核，以及下丘脑的视交叉上核、弓状核和背内侧核。PV后区比PV前区向背侧纹状体以及杏仁核的中央核和基底核的分布更密集。PT的投射与PV的投射有显著重叠，但也存在一些重要差异。PT向BST和杏仁核的分布比PV少，但向内侧前额叶皮质和内嗅皮质以及海马腹侧下托的分布要密集得多。如本文所述，PV/PT接收来自脑干、下丘脑和边缘前脑的大量传入信息，这些信息与动物的觉醒和注意力状态有关，并且似乎会将这些信息传递到边缘前脑的结构中，以便对不断变化的环境条件选择适当的反应。根据在任何一个时间点到达PV/PT的与情绪相关信息的具体组成，PV/PT似乎通过作用于边缘前脑，在一系列结果中引导行为朝向特定结果。
