van Groen Thomas, Kadish Inga, Wyss J Michael
Department of Neuroscience and Neurology, University of Kuopio, Kuopio, Finland.
Brain Res Bull. 2002;57(3-4):553-6. doi: 10.1016/s0361-9230(01)00683-9.
Both differences and similarities exist between mammalian species in the projections from entorhinal cortex to the hippocampal formation. In most species, layer II cells of the entorhinal cortex project to the dentate gyrus, and they terminate in the outer two-thirds of the molecular layer of the dentate gyrus. The axons from layer III cells project bilaterally to areas CA(1) and CA(3) of the hippocampus, terminating in the stratum lacunosum moleculare. We have analyzed these projections in mice, and in general, the entorhinal cortex-to-hippocampus projections are similar to those in rats. Axons from layer II neurons terminate in the outer and middle thirds of the molecular layer of the dentate gyrus, and axons from layer III neurons terminate bilaterally in the stratum lacunosum moleculare of areas CA(1) and CA(3), and in the molecular layer of the subiculum. However, in contrast to rat, mouse entorhinal cortex neurons do not appreciably project to the contralateral dentate gyrus. Most species, including mice, show a similar topographical organization of the entorhinal-hippocampal projections, with neurons in the lateral part of both the lateral and medial entorhinal cortex projecting to the dorsal part or septal pole of the hippocampus, whereas the projection to the ventral hippocampus originates primarily from neurons in medial parts of the entorhinal cortex.
在从内嗅皮层到海马结构的投射方面，哺乳动物物种之间既存在差异也有相似之处。在大多数物种中，内嗅皮层的II层细胞投射到齿状回，它们终止于齿状回分子层的外侧三分之二。III层细胞的轴突双侧投射到海马的CA(1)区和CA(3)区，终止于分子层的腔隙层。我们已经分析了小鼠的这些投射，总体而言，内嗅皮层到海马的投射与大鼠的相似。II层神经元的轴突终止于齿状回分子层的外侧和中间三分之一，III层神经元的轴突双侧终止于CA(1)区和CA(3)区分子层的腔隙层以及下托的分子层。然而，与大鼠不同的是，小鼠内嗅皮层神经元不会明显投射到对侧齿状回。包括小鼠在内的大多数物种，在内嗅-海马投射方面表现出相似的拓扑组织，外侧和内侧内嗅皮层外侧部分的神经元投射到海马的背侧部分或隔极，而投射到腹侧海马的主要起源于内嗅皮层内侧部分的神经元。
