Objective: To investigate the projections the cerebrospinal fluid-contacting (CSF-contacting) nucleus receives from the diencephalon and to speculate on the functional significance of these connections.

Methods: The retrograde tracer cholera toxin B subunit (CB) was injected into the CSF-contacting nucleus in SD rats according to the experimental formula of the stereotaxic coordinates. Animals were perfused 7–10 days after the injection, and the diencephalon was sliced at 40 μm with a freezing microtome. CB-immunofluorescence was performed on all diencephalic sections. The features of CB-positive neuron distribution in the diencephalon were observed with a fluorescence microscope.

Results: The retrograde labeled CB-positive neurons were found in the epithalamus, subthalamus, and hypothalamus. Three functional diencephalic areas including 43 sub-regions revealed projections to the CSF-contacting nucleus. The CB-positive neurons were distributed in different density ranges: sparse, moderate, and dense.

Conclusion: Based on the connectivity patterns of the CSF-contacting nucleus that receives anatomical inputs from the diencephalon, we preliminarily assume that the CSF-contacting nucleus participates in homeostasis regulation, visceral activity, stress, emotion, pain and addiction, and sleeping and arousal. The present study firstly illustrates the broad projections of the CSF-contacting nucleus from the diencephalon, which implies the complicated functions of the nucleus especially for the unique roles of coordination in neural and body fluids regulations.

目的：调查脑脊液接触（CSF接触）核从间脑收到的预测，并推测这些连接的功能意义。

方法：根据立体定位坐标的实验公式，将逆行示踪示踪霍乱毒素B亚基（CB）注入SD大鼠的CSF接触核中。注射后7-10天为动物灌流，并用冷冻切片机将40微米的二脑切成薄片。在所有二脑切片上进行CB免疫荧光。用荧光显微镜观察脑中CB阳性神经元的分布特征。

结果：在上丘脑，丘脑下和下丘脑中发现了逆行标记的CB阳性神经元。三个功能性双脑区域，包括43个子区域，揭示了与CSF接触核的投影。CB阳性神经元分布在不同的密度范围内：稀疏，中等和密集。

结论基于CSF接触核从双脑接受解剖学输入的连通性模式，我们初步假设CSF接触核参与体内稳态调节，内脏活动，压力，情绪，疼痛和成瘾以及睡眠和唤醒。本研究首先从中脑阐明了CSF接触核的广泛预测，这暗示了核的复杂功能，尤其是对于神经和体液调节中的独特协调作用。