Butler A B
Ivory Tower Neurobiology Institute, Arlington, VA 22207.
Brain Res Brain Res Rev. 1994 Jan;19(1):66-101. doi: 10.1016/0165-0173(94)90004-3.
The large body of evidence that supports the hypothesis that the dorsal cortex and dorsal ventricular ridge of non-mammalian (non-synapsid) amniotes form the dorsal pallium and are homologous as a set of specified populations of cells to respective sets of cells in mammalian isocortex is reviewed. Several recently taken positions that oppose this hypothesis are examined and found to lack a solid foundation. A cladistic analysis of multiple features of the dorsal pallium in amniotes was carried out in order to obtain a morphotype for the common ancestral stock of all living amniotes, i.e., a captorhinomorph amniote. A previous cladistic analysis of the dorsal thalamus (Butler, A.B., The evolution of the dorsal thalamus of jawed vertebrates, including mammals: cladistic analysis and a new hypothesis, Brain Res. Rev., 19 (1994) 29-65; this issue, previous article) found that two fundamental divisions of the dorsal thalamus can be recognized--termed the lemnothalamus in reference to predominant lemniscal sensory input and the collothalamus in reference to predominant input from the midbrain roof. These two divisions are both elaborated in amniotes in that their volume is increased and their nuclei are laterally migrated in comparison with anamniotes. The present cladistic analysis found that two corresponding, fundamental divisions of the dorsal pallium were present in captorhinomorph amniotes and were expanded relative to their condition in anamniotes. Both the lemnothalamic medial pallial division and the collothalamic lateral pallial division were subsequently further markedly expanded in the synapsid line leading to mammals, along with correlated expansions of the lemnothalamus and collothalamus. Only the collothalamic lateral pallial division--along with the collothalamus--was subsequently further markedly expanded in the non-synapsid amniote line that gave rise to diapsid reptiles, birds and turtles. In the synapsid line leading to mammals, an increase in the degree of radial organization of both divisions of the dorsal pallium also occurred, resulting in an 'outside-in' migration pattern during development. The lemnothalamic medial division of the dorsal pallium has two parts. The medial part forms the subicular, cingulate, prefrontal, sensorimotor, and related cortices in mammals and the medial part of the dorsal cortex in non-synapsid amniotes. The lateral part forms striate cortex in mammals and the lateral part of dorsal cortex (or pallial thickening or visual Wulst) in non-synapsid amniotes. Specific fields within the collothalamic lateral division of the dorsal pallium form the extrastriate, auditory, secondary somatosensory, and related cortices in mammals and the visual, auditory, somatosensory, and related areas of the dorsal ventricular ridge in non-synapsid amniotes.
本文回顾了大量证据，这些证据支持以下假说：非哺乳类（非合弓纲）羊膜动物的背侧皮质和背侧脑室嵴形成背侧大脑皮质，并且作为一组特定的细胞群，与哺乳类大脑皮质中的相应细胞群同源。本文还审视了最近一些反对该假说的观点，发现这些观点缺乏坚实的基础。为了获得所有现存羊膜动物共同祖先种群（即杯鼻龙类羊膜动物）的形态型，对羊膜动物背侧大脑皮质的多个特征进行了分支系统分析。先前对背侧丘脑的分支系统分析（巴特勒，A.B.，有颌脊椎动物包括哺乳动物背侧丘脑的进化：分支系统分析及新假说，《脑研究评论》，19（1994）29 - 65；本期，前文）发现，可以识别出背侧丘脑的两个基本分区——根据主要的薄束感觉输入称为丘系丘脑，根据来自中脑顶盖的主要输入称为顶盖丘脑。与无羊膜动物相比，这两个分区在羊膜动物中都有扩展，即它们的体积增大且核向外侧迁移。目前的分支系统分析发现，杯鼻龙类羊膜动物中存在背侧大脑皮质的两个相应基本分区，并且相对于它们在无羊膜动物中的状态有所扩展。在通向哺乳动物的合弓纲谱系中，丘系丘脑内侧大脑皮质分区和顶盖丘脑外侧大脑皮质分区随后都进一步显著扩展，同时丘系丘脑和顶盖丘脑也相应扩展。在导致双孔类爬行动物、鸟类和龟类的非合弓纲羊膜动物谱系中，只有顶盖丘脑外侧大脑皮质分区——连同顶盖丘脑——随后进一步显著扩展。在通向哺乳动物的合弓纲谱系中，背侧大脑皮质两个分区的放射状组织程度也有所增加，导致在发育过程中出现“由外向内”的迁移模式。背侧大脑皮质的丘系丘脑内侧分区有两个部分。内侧部分在哺乳动物中形成海马旁回、扣带回、前额叶、感觉运动及相关皮质，在非合弓纲羊膜动物中形成背侧皮质的内侧部分。外侧部分在哺乳动物中形成纹状皮质，在非合弓纲羊膜动物中形成背侧皮质的外侧部分（或大脑皮质增厚或视觉顶叶）。背侧大脑皮质的顶盖丘脑外侧分区内的特定区域在哺乳动物中形成纹外、听觉、次级躯体感觉及相关皮质，在非合弓纲羊膜动物中形成背侧脑室嵴的视觉、听觉、躯体感觉及相关区域。
