The forebrain of the Pacific hagfish: a cladistic reconstruction of the ancestral craniate forebrain.
The forebrain of the Pacific hagfish: a cladistic reconstruction of the ancestral craniate forebrain.
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太平洋盲鳗的前脑：祖先颅骨前脑的分支重建。
DOI：
10.1159/000108540
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Northcutt,RG
中科院分区：
文献类型：
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作者：
Wicht,H;Northcutt,RG
描述了太平洋盲鳗的前脑的形态、细胞结构和次级嗅觉投影。成年盲鳗的前脑心室系统大大减少，但仍然可以识别心室结构的痕迹。为了阐明前脑内的地形关系，我们提供了心室系统的三维重建，包括退化部分。地形学和胚胎学使我们得出结论，先前作者的“海马体原基”是间脑结构。由于地形和形态学的原因，我们将之前作者的“基底区”解释为视前区的一部分，并将所谓的“前嗅核”的一部分确定为纹状体的同源物。层状白质以次级嗅觉投射为主，表现出高度的区域性细胞结构特化，整个前脑也是如此。在盲鳗的前脑中总共鉴定出42个细胞群（例如，在七鳃鳗中只有25个细胞群）。这种令人惊讶的高度细胞结构复杂性促使我们重新审视颅脑的系统发育历史，并考虑到这种复杂性。在这篇论文中，我们使用进化的方法来重建一个形态，我们得出结论，最早的头盖骨的前脑可能比以前认为的更复杂。这种重建包括关于早期颅脑的一般形态、次级嗅觉系统和视觉系统的假设，以及前脑主要分支的相对大小。
The forebrain of the Pacific hagfish is described with regard to its morphology, cytoarchitecture, and secondary olfactory projections. The forebrain ventricular system is greatly reduced in adult hagfishes, although vestiges of ventricular structures can still be recognized. In order to clarify topographical relationships within the forebrain, we provide a three-dimensional reconstruction of the ventricular system, including the vestigial portions. Topography and embryology lead us to conclude that the 'primordium hippocampi' of previous authors is a diencephalic structure. For topographical and hodological reasons, we interpret the 'area basalis' of previous authors to be part of the preoptic region, and we identify a part of the so-called 'nucleus olfactorius anterior' as the homologue of the striatum. The laminated pallium is dominated by secondary olfactory projections and shows a high degree of regional cytoarchitectural specialization, as does the entire forebrain. In all, 42 cell groups are identified in the forebrain of hagfishes (compared to only about 25 in lampreys, for example). This surprisingly high degree of cytoarchitectural complexity prompted us to re-examine the phylogenetic history of craniate brains with this complexity in mind. In this paper we use cladistic methodology to reconstruct a morphotype, and we conclude that the forebrains of the earliest craniates may have been more complex than previously believed. This reconstruction includes hypotheses regarding the general morphology, secondary olfactory system, and visual system, as well as the relative sizes of major divisions of the forebrain in the earliest craniates.