Jacobs M S, McFarland W L, Morgane P J
Brain Res Bull. 1979;4 Suppl 1:1-108. doi: 10.1016/0361-9230(79)90299-5.
The hippocampal formation or archicortical division of the rhinecephalon of the bottlenose dolphin, Tursiops truncatus, is described from the standpoint of its gross topographic relations and cytoarchitecture. A feature of the dolphin brain, which lacks olfactory bulbs and peduncles, is the striking reduction of the archicortical relative to the paleocortical formations. The small, poorly developed archicortex covered by massive epihippocampal portions of the hemispheres (parietal and temporal lobes), appears greatly reduced relative to the large, well developed olfactory lobes which are covered by small epistriatal portions of the hemispheres (orbital lobes). The archicortex exhibits three junctional zones with the paleocortex, two laterally in the unci and one anteriorly in the septal area. Despite the small size of the hippocampal formations, the general topographic disposition of its cytoarchitectonic areas and their cellular organization in Tursiops have many features that are similar to those in other placental mammals. The archicortex is subdivisible into four major sectors: temporal, retrosplenial, supracallosal and subcallosal. With the exception of the temporal sector, cytoarchitectonic areas of the other sectors are variously attenuated and poorly differentiated, particularly the dentate area and the hippocampal areas H5 and H4. Here, the dentate area and hippocampal areas H5 and H4 which are present along the paradentate bank of the hippocampal sulcus, extend to the level of the oblique sulcus of the parahippocampal gyrus and then disappear. Hippocampal areas H3, H2 and H1 are also clear in the floor and along the parahippocampal bank of the hippocampal sulcus in the temporal sector. These areas are less definable as they extend beyond the oblique sulcus into the retrosplenial sector and are difficult to recognize as distinct areas in the supracallosal and subcallosal sectors of the archicortex. The archicortex is demarcated bilaterally from limbic formations in the border of the hemisphere by segments of the rhinic cleft which are very clear. Equally clear is the cytoarchitectonic demarcation of the archicortex from the neocortex in the border (limbus) of each hemisphere, i.e., where the subiculum abuts against the presubiculum. The subicular area, best expressed in the temporal sector, extends anteriorly over the corpus callosum to the subcallosal gyrus and, throughout its extent from the uncal to the septal junction, is clearly demarcated from limbic neocortex by a transition zone characterized by archicortical cells merging with cells in the deep layer of the bordering neocortex. Overall, the archicortical formations of the dolphin and other whale brains we have examined exhibit many regional peculiarities that we have described, both grossly and architectonically, with emphasis on the comparative anatomical approach.
从宽吻海豚（Tursiops truncatus）大脑边缘系统的海马结构或原皮质部分的大体地形关系和细胞结构角度进行了描述。海豚大脑的一个特征是缺乏嗅球和嗅束，相对于古皮质结构，原皮质显著减少。被半球（顶叶和颞叶）大量海马旁部分覆盖的小而发育不良的原皮质，相对于被半球小的嗅纹旁部分（眶叶）覆盖的大而发育良好的嗅叶，显得大为减少。原皮质与古皮质有三个连接区，两个在钩的外侧，一个在前部的隔区。尽管海马结构较小，但宽吻海豚中海马细胞构筑区的总体地形分布及其细胞组织具有许多与其他胎盘哺乳动物相似的特征。原皮质可细分为四个主要部分：颞叶、压后叶、胼胝体上区和胼胝体下区。除颞叶部分外，其他部分的细胞构筑区有不同程度的变薄和分化不良，特别是齿状区以及海马区H5和H4。在这里，沿着海马沟齿状缘存在的齿状区以及海马区H5和H4，延伸至海马旁回斜沟水平，然后消失。海马区H3、H2和H1在颞叶部分的海马沟底部和海马旁缘也很清晰。随着这些区域延伸至斜沟之外进入压后叶部分，它们变得较难界定，并且在原皮质的胼胝体上区和胼胝体下区难以识别为不同的区域。原皮质在半球边缘与边缘系统结构由非常清晰的鼻裂段双侧分界。同样清晰的是，在每个半球的边缘（边缘）处，原皮质与新皮质之间的细胞构筑分界，即海马下托与前海马下托相邻的地方。海马下托区在颞叶部分最为明显，向前延伸至胼胝体，到达胼胝体下回，并且在从钩到隔区连接的整个范围内，通过一个以原皮质细胞与相邻新皮质深层细胞融合为特征的过渡区，与边缘新皮质明显分界。总体而言，我们所研究的海豚和其他鲸类大脑的原皮质结构在大体和结构上都表现出许多我们所描述的区域特殊性，重点采用了比较解剖学方法。
