Using Cerebral Characters to Reconstruct Deep Metazoan Phylogeny: Comparative neuroarchitecture of the brain in annelids, molluscs and arthropods analyzed with confocal laser scanning microscopy

节肢动物大脑的许多解剖特征在进化过程中被高度保守，包括神经丸的存在和基本神经结构，如中枢体和蘑菇体。因此，这些特征是推导节肢动物与动物界其他主要类群的系统发育关系的理想标记。虽然关于真节肢动物大脑结构的文献很多，但对大多数其他无脊椎动物神经节内部结构的研究却很少。在“深层后生动物系统发育”一章的开头，我们详细分析了真足类和爪足类的基础代表动物的神经结构，从而对全节肢动物大脑的基础模式有了更清晰的认识。我们已经调查了几个代表的环节动物的细胞解剖，并在第二个应用期间，软体动物。该项目的目的是比较节肢动物与环节动物和软体动物大脑的地面模式。对环节动物大脑的分析已进入高级阶段，并将以对特别感兴趣的大脑中心的详细调查作为补充。我们将继续研究基底软体动物的大脑神经节，这是一个在DMP中没有被形态学项目覆盖的群体。使用免疫荧光抗体技术和最先进的共聚焦激光扫描显微镜以及3d重建将使我们能够详细分析解剖数据。鉴定同源脑结构的方法一致性和严格标准将导致一组可比的特征。与来自DMP其他成员的结果一起，获得的数据集将在DMP的最后阶段进行综合系统发育分析。

Numerous anatomical features of the brain of arthropods are highly conserved during evolution, including the presence and basic neuroarchitecture of neuropils such as the central body and the mushroom bodies. These features are therefore ideal markers from which to derive phylogenetic relationships of arthropods with other major groups of the animal kingdom. While the literature on euarthropod brain architecture is abundant there have been only sparse and superficial reports examining the internal structure of cerebral ganglia of most other invertebrate phyla. In the beginning of “Deep Metazoan Phylogeny” we have analyzed in detail the neuroarchitecture of basal representatives of euarthopods and of onychophorans, resulting in a clearer picture of the ground pattern of the brain of panarthropods. We have investigated the cellular anatomy of several representatives of the Annelida, and during the second application period, of the Mollusca. The aim of the project is to compare the ground pattern of the arthropod brain to that of annelids and molluscs. The analysis of the annelid brain is in an advanced stage and will be supplemented by detailed investigations of brain centers of special interest. We will continue to investigate cerebral ganglia of basal molluscs, a group that is otherwise not covered by morphological projects within DMP. The use of immunofluorescence antibody techniques and state-of-the-art confocal laser scanning microscopy along with 3D-reconstructions will allow us to analyze the anatomical data in detail. Methodological consistency and strict criteria for identifying homologous brain structures will result in a comparable set of characters. Together with results from other members of DMP the acquired set of data will be subjected to a combined phylogenetic analysis in the concluding phase of DMP.