Developmental Neurobiology, Kyoto Prefectural University of Medicine Kyoto, Japan ; Japan Science and Technology Agency, PRESTO Kawaguchi, Japan.
Department of Biophysics, Graduate School of Science, Kyoto University Kyoto, Japan.
Front Neurosci. 2015 Feb 24;9:45. doi: 10.3389/fnins.2015.00045. eCollection 2015.
The mammalian neocortex is a remarkable structure that is characterized by tangential surface expansion and six-layered lamination. However, how the mammalian neocortex emerged during evolution remains elusive. Because all modern reptiles have a homolog of the neocortex at the dorsal pallium, developmental analyses of the reptilian cortex are valuable to explore the origin of the neocortex. However, reptilian cortical development and the underlying molecular mechanisms remain unclear, mainly due to technical difficulties with sample collection and embryonic manipulation. Here, we introduce a method of embryonic manipulations for the Madagascar ground gecko and Chinese softshell turtle. We established in ovo electroporation and an ex ovo culture system to address neural stem cell dynamics, neuronal differentiation and migration. Applications of these techniques illuminate the developmental mechanisms underlying reptilian corticogenesis, which provides significant insight into the evolutionary steps of different types of cortex and the origin of the mammalian neocortex.
哺乳动物大脑皮层是一种具有显著特征的结构，其特征在于切向表面扩展和六层分层。然而，哺乳动物大脑皮层在进化过程中是如何出现的仍然难以捉摸。由于所有现代爬行动物的背侧脑皮层都有大脑皮层的同源物，因此对爬行动物皮层的发育分析对于探索大脑皮层的起源很有价值。然而，爬行动物皮层的发育及其潜在的分子机制仍不清楚，主要是由于样本收集和胚胎操作的技术困难。在这里，我们介绍了马达加斯加地蜥和中国鳖胚胎操作的方法。我们建立了鸡胚电穿孔和鸡胚外培养系统，以研究神经干细胞的动力学、神经元分化和迁移。这些技术的应用阐明了爬行动物皮质发生的发育机制，为不同类型皮质的进化步骤以及哺乳动物大脑皮层的起源提供了重要的见解。
