An animal’s nervous system changes as its body grows from birth to adulthood and its behaviours mature^{1,2,3,4,5,6,7,8}. The form and extent of circuit remodelling across the connectome is unknown^{3,9,10,11,12,13,14,15}. Here we used serial-section electron microscopy to reconstruct the full brain of eight isogenic Caenorhabditis elegans individuals across postnatal stages to investigate how it changes with age. The overall geometry of the brain is preserved from birth to adulthood, but substantial changes in chemical synaptic connectivity emerge on this consistent scaffold. Comparing connectomes between individuals reveals substantial differences in connectivity that make each brain partly unique. Comparing connectomes across maturation reveals consistent wiring changes between different neurons. These changes alter the strength of existing connections and create new connections. Collective changes in the network alter information processing. During development, the central decision-making circuitry is maintained, whereas sensory and motor pathways substantially remodel. With age, the brain becomes progressively more feedforward and discernibly modular. Thus developmental connectomics reveals principles that underlie brain maturation.

动物的神经系统会随着其身体从出生到成年的生长以及其行为的成熟而发生变化^{1,2,3,4,5,6,7,8}。跨连接组的电路重塑的形式和程度未知^{3,9,10,11,12,13,14,15}。在这里，我们使用连续切片电子显微镜重建了八种等基因秀丽隐杆线虫的全脑跨产后阶段的个体来研究它如何随年龄变化。大脑的整体几何形状从出生到成年都得到了保留，但是在这个一致的支架上出现了化学突触连接的实质性变化。比较个体之间的连接组揭示了连接性的显着差异，这使得每个大脑都有部分独特性。比较成熟过程中的连接组揭示了不同神经元之间一致的布线变化。这些变化改变了现有连接的强度并创建了新的连接。网络的集体变化改变了信息处理。在开发过程中，中央决策电路得以维持，而感觉和运动通路则大幅重塑。随着年龄的增长，大脑变得越来越前馈和明显模块化。