AUTHOR=Song Si-Yuan , Li Ying , Zhai Xiao-Meng , Li Yue-Hao , Bao Cheng-Yi , Shan Cheng-Jing , Hong Jia , Cao Jun-Li , Zhang Li-Cai 

TITLE=Monosynaptic Input Mapping of Diencephalic Projections to the Cerebrospinal Fluid-Contacting Nucleus in the Rat

JOURNAL=Frontiers in Neuroanatomy

VOLUME=Volume 14 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/neuroanatomy/articles/10.3389/fnana.2020.00007

DOI=10.3389/fnana.2020.00007

ISSN=1662-5129

ABSTRACT=Objective: To investigate the projections the cerebrospinal fluid-contacting (CSF-contacting) nucleus receives from the diencephalon and to speculate on 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 d 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 labelled CB-positive neurons were found in the epithalamus, subthalamus and hypothalamus. Three functional diencephalic areas including forty-three 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 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.