Embryonic boundaries were first described in Drosophila, and then in vertebrate embryos, as cellular interfaces between compartments. They display signaling properties and in vertebrates might allocate cells fated to different anatomical structures, or cells that will play different functions over time. One of the vertebrate embryonic structures with boundaries is the hindbrain, the posterior brain vesicle, which is transitory segmented upon morphogenesis. The hindbrain is formed by iterative units called rhombomeres that constitute units of gene expression and cell-lineage compartments. Rhombomeric cells are segregated by interhombomeric boundaries, which are prefigured by sharp gene expression borders. Hindbrain boundaries were first described as static groups of cells. However, later discoveries demonstrated the dynamic behavior of this specific cell population. They play distinct functional properties during brain morphogenesis that partially overlap on time, starting as a mechanical barrier to prevent cell intermingling, becoming a signaling hub, to finally constitute a group of proliferating progenitors providing differentiated neurons to the system. In this review, I try to give a more functional overview of this segmentation process and in particular of hindbrain boundaries. I will discuss the new challenges in the field on how to integrate cell fate specification and morphogenesis during brain embryonic development.

胚胎边界首先在果蝇中被描述，然后在脊椎动物胚胎中被描述为隔间之间的细胞界面。它们显示信号特性，并且在脊椎动物中可能会将细胞分配到不同的解剖结构，或者随着时间的推移将发挥不同功能的细胞。具有边界的脊椎动物胚胎结构之一是后脑，即后脑囊泡，它在形态发生时被暂时分割。后脑由称为菱形体的迭代单元形成，这些单元构成基因表达单元和细胞谱系隔室。菱形细胞由菱形间边界分隔，这些边界以尖锐的基因表达边界为先导。后脑边界首先被描述为静态的细胞群。然而，后来的发现证明了这种特定细胞群的动态行为。它们在大脑形态发生过程中发挥不同的功能特性，在时间上部分重叠，从防止细胞混合的机械屏障开始，成为信号中心，最终构成一组增殖祖细胞，为系统提供分化的神经元。在这篇评论中，我试图对这个分割过程，特别是后脑边界进行更实用的概述。我将讨论如何在脑胚胎发育过程中整合细胞命运规范和形态发生领域的新挑战。成为信号中心，最终构成一组增殖祖细胞，为系统提供分化的神经元。在这篇评论中，我尝试对这个分割过程，特别是后脑边界进行更实用的概述。我将讨论如何在脑胚胎发育过程中整合细胞命运规范和形态发生领域的新挑战。成为信号中心，最终构成一组增殖祖细胞，为系统提供分化的神经元。在这篇评论中，我尝试对这个分割过程，特别是后脑边界进行更实用的概述。我将讨论如何在脑胚胎发育过程中整合细胞命运规范和形态发生领域的新挑战。