Oxytocin (OXT) plays important roles in autonomic control and behavioral modulation. However, it is unknown how the projection patterns of OXT neurons align with underlying physiological functions. Here, we present the reconstructed single-neuron, whole-brain projectomes of 264 OXT neurons of the mouse paraventricular hypothalamic nucleus (PVH) at submicron resolution. These neurons hierarchically clustered into two groups, with distinct morphological and transcriptional characteristics and mutually exclusive projection patterns. Cluster 1 (177 neurons) axons terminated exclusively in the median eminence (ME) and have few collaterals terminating within hypothalamic regions. By contrast, cluster 2 (87 neurons) sent wide-spread axons to multiple brain regions, but excluding ME. Dendritic arbors of OXT neurons also extended outside of the PVH, suggesting capability to sense signals and modulate target regions. These single-neuron resolution observations reveal distinct OXT subpopulations, provide comprehensive analysis of their morphology, and lay the structural foundation for better understanding the functional heterogeneity of OXT neurons.

中文翻译：

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小鼠室旁下丘脑核催产素神经元的单神经元投影揭示了相互排斥的投影模式

催产素（OXT）在自主控制和行为调节中发挥重要作用。然而，OXT 神经元的投射模式如何与潜在的生理功能相一致尚不清楚。在这里，我们展示了小鼠下丘脑室旁核 (PVH) 264 个 OXT 神经元的亚微米分辨率重建单神经元全脑投影。这些神经元分层聚集成两组，具有不同的形态和转录特征以及相互排斥的投射模式。簇 1（177 个神经元）轴突仅终止于正中隆起 (ME)，并且很少有侧枝终止于下丘脑区域。相比之下，簇 2（87 个神经元）将广泛分布的轴突发送到多个大脑区域，但不包括 ME。 OXT 神经元的树突状乔木也延伸到 PVH 之外，表明其具有感知信号和调节目标区域的能力。这些单神经元分辨率观察揭示了不同的 OXT 亚群，提供了对其形态的全面分析，并为更好地理解 OXT 神经元的功能异质性奠定了结构基础。