Morgane P J, Glezer I I, Jacobs M S
Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts 01545.
J Comp Neurol. 1988 Jul 1;273(1):3-25. doi: 10.1002/cne.902730103.
On cytoarchitectonic grounds we have identified two distinct types of cortical formations composing the lateral gyrus (visual cortex) of the dolphin and have termed these heterolaminar cortex and homolaminar cortex. The heterolaminar cortex occupies the medial and lateral banks of the entolateral sulcus whereas the homolaminar cortex occupies the remainder of the lateral gyrus both lateral and medial to the entolateral sulcus. Each of these cortices exhibits special cytoarchitectonic features, a major difference being that heterolaminar cortex contains an incipient layer IV whereas layer IV is clearly absent in homolaminar cortex. Quantitative imaging procedures reveal that there is greater laminar differentiation in heterolaminar than in homolaminar cortex. Golgi analysis of neuronal forms and dendritic architecture confirms this distinction between the two types of cortex composing the lateral gyrus. Computer-assisted morphometric methods have been applied to both types of cortex and indicate by a variety of parameters several quantitative differences in the cellular numbers, types, and organization in each type of cortex. Both types of cortex, homolaminar and heterolaminar, exhibit a markedly higher cellular density in the posterior sector of the lateral gyrus than in the anterior sector. We have also for the first time been able to identify a columnar type of organization of the cetacean visual cortex and have described two types of cytoarchitectonic columns, major and minor, in each of these types of cortex. Comparisons in organization of these basic columnar units between the bat, representing a prototypic brain, and the dolphin reveal many similarities but also major quantitative differences in type of organization between the visual cortices in these species. Marked differences are also seen between the cytoarchitectonic columnar organization of the visual cortices in the dolphin and columnar organization of striate cortex in the human brain, the number of columns per unit of cortex in the human being almost twice that seen in the dolphin brain. Some phylogenetic implications of these findings are discussed in relation to the so-called "initial" type of cortical organization reconstructed largely by retrospective inference.
基于细胞构筑学原理，我们识别出构成海豚外侧回（视觉皮层）的两种不同类型的皮质结构，并将其分别命名为异层皮质和同层皮质。异层皮质占据外侧内沟的内侧和外侧壁，而同层皮质占据外侧回的其余部分，位于外侧内沟的外侧和内侧。这些皮质各自呈现出特殊的细胞构筑特征，一个主要区别在于异层皮质含有初期的第IV层，而同层皮质中明显没有第IV层。定量成像程序显示，异层皮质中的层状分化比同层皮质更为显著。对神经元形态和树突结构的高尔基分析证实了构成外侧回的这两种皮质类型之间的差异。计算机辅助形态测量方法已应用于这两种皮质类型，并通过各种参数表明每种皮质类型在细胞数量、类型和组织方面存在若干定量差异。同层皮质和异层皮质这两种类型的皮质，在外侧回后部的细胞密度均明显高于前部。我们还首次能够识别出鲸类视觉皮层的柱状组织类型，并描述了在每种皮质类型中的两种细胞构筑柱，即主要柱和次要柱。将代表典型大脑的蝙蝠与海豚在这些基本柱状单元的组织方面进行比较，结果显示出许多相似之处，但这些物种的视觉皮层在组织类型上也存在主要的定量差异。在海豚视觉皮层的细胞构筑柱状组织与人脑纹状皮层的柱状组织之间也观察到明显差异，人类大脑每单位皮质的柱数量几乎是海豚大脑的两倍。本文结合主要通过回顾性推断重建的所谓“初始”类型的皮质组织，讨论了这些发现的一些系统发育意义。
