Agster Kara L, Tomás Pereira Inês, Saddoris Michael P, Burwell Rebecca D
Department of Neuroscience, Brown University, Providence, Rhode Island.
Department of Cognitive, Linguistic, and Psychological Sciences, Brown University, Providence, Rhode Island.
Hippocampus. 2016 Sep;26(9):1213-30. doi: 10.1002/hipo.22600. Epub 2016 May 24.
This is the second of two studies detailing the subcortical connections of the perirhinal (PER), the postrhinal (POR) and entorhinal (EC) cortices of the rat. In the present study, we analyzed the subcortical efferents of the rat PER areas 35 and 36, POR, and the lateral and medial entorhinal areas (LEA and MEA). Anterograde tracers were injected into these five regions, and the resulting density of fiber labeling was quantified in an extensive set of subcortical structures. Density and topography of fiber labeling were quantitatively assessed in 36 subcortical areas, including olfactory structures, claustrum, amygdala nuclei, septal nuclei, basal ganglia, thalamic nuclei, and hypothalamic structures. In addition to reporting the density of labeled fibers, we incorporated a new method for quantifying the size of anterograde projections that takes into account the volume of the target subcortical structure as well as the density of fiber labeling. The PER, POR, and EC displayed unique patterns of projections to subcortical areas. Interestingly, all regions examined provided strong input to the basal ganglia, although the projections arising in the PER and LEA were stronger and more widespread. PER areas 35 and 36 exhibited similar pattern of projections with some differences. PER area 36 projects more heavily to the lateral amygdala and much more heavily to thalamic nuclei including the lateral posterior nucleus, the posterior complex, and the nucleus reuniens. Area 35 projects more heavily to olfactory structures. The LEA provides the strongest and most widespread projections to subcortical structures including all those targeted by the PER as well as the medial and posterior septal nuclei. POR shows fewer subcortical projections overall, but contributes substantial input to the lateral posterior nucleus of the thalamus. The MEA projections are even weaker. Our results suggest that the PER and LEA have greater influence over olfactory, amygdala, and septal nuclei, whereas PER area 36 and the POR have greater influence over thalamic nuclei. © 2016 Wiley Periodicals, Inc.
这是两项详细研究大鼠嗅周皮质（PER）、嗅后皮质（POR）和内嗅皮质（EC）皮质下连接的研究中的第二项。在本研究中，我们分析了大鼠PER的35区和36区、POR以及外侧和内侧内嗅区（LEA和MEA）的皮质下传出纤维。将顺行示踪剂注入这五个区域，并在大量皮质下结构中对由此产生的纤维标记密度进行定量分析。在36个皮质下区域对纤维标记的密度和拓扑结构进行了定量评估，这些区域包括嗅觉结构、屏状核、杏仁核、隔核、基底神经节、丘脑核和下丘脑结构。除了报告标记纤维的密度外，我们还采用了一种新方法来量化顺行投射的大小，该方法考虑了目标皮质下结构的体积以及纤维标记的密度。PER、POR和EC向皮质下区域投射的模式独特。有趣的是，所有检查的区域都向基底神经节提供了强大的输入，尽管起源于PER和LEA的投射更强且更广泛。PER的35区和36区表现出相似的投射模式，但存在一些差异。PER的36区向外侧杏仁核投射更多，向包括外侧后核、后复合体和 reunien 核在内的丘脑核投射更多。35区向嗅觉结构投射更多。LEA向皮质下结构提供最强且最广泛的投射，包括PER靶向的所有结构以及内侧和后隔核。总体而言，POR的皮质下投射较少，但对丘脑外侧后核有大量输入。MEA的投射甚至更弱。我们的结果表明，PER和LEA对嗅觉、杏仁核和隔核的影响更大，而PER的36区和POR对丘脑核的影响更大。© 2016威利期刊公司
