The nervous system contains complex circuits comprising thousands of cell types and trillions of connections. Here, we discuss how the field of "developmental systems neuroscience" combines the molecular and genetic perspectives of developmental neuroscience with the (typically adult-focused) functional perspective of systems neuroscience. This combination of approaches is critical to understanding how a handful of cells eventually produce the wide range of behaviors necessary for survival. Functional circuit development typically lags behind neural connectivity, leading to intermediate stages of neural activity that are either not seen in adults or, if present, are considered pathophysiological. Developmental systems neuroscience examines these intermediate stages of neural activity, mapping out the critical phases and inflection points of neural circuit function to understand how neural activity and behavior emerge across development. Beyond understanding typical development, this approach provides invaluable insight into the pathophysiology of neurodevelopmental disorders by identifying when and how functional development diverges between health and disease. We argue that developmental systems neuroscience will identify important periods of neural development, reveal novel therapeutic windows for treatment, and set the stage to answer fundamental questions about the brain in health and disease.

神经系统包含复杂的回路，包括数千种细胞类型和数万亿个连接。在这里，我们讨论了“发育系统神经科学”领域如何将发育神经科学的分子和遗传学观点与系统神经科学的（通常以成人为重点的）功能观点相结合。这种方法的组合对于理解少数细胞如何最终产生生存所需的广泛行为至关重要。功能回路的发育通常滞后于神经连接，导致神经活动的中间阶段，这些阶段要么在成人中看不到，要么如果存在，则被认为是病理生理学的。发育系统神经科学研究神经活动的这些中间阶段，绘制出神经回路功能的关键阶段和拐点，以了解神经活动和行为在发育过程中是如何出现的。除了了解典型发育之外，这种方法还通过确定功能和疾病之间的功能发育何时以及如何分化，为神经发育障碍的病理生理学提供了宝贵的见解。我们认为，发育系统神经科学将确定神经发育的重要时期，揭示新的治疗窗口，并为回答有关大脑健康和疾病的基本问题奠定基础。