The CSF-contacting nucleus regulates learning and memory through synaptic connections with the hippocampus.

The cerebrospinal fluid (CSF)-contacting nucleus is a special nucleus. To study the mechanism of the CSF-contacting nucleus in learning and memory, we used classic retrograde tracing methods to observe the synaptic connections between the CSF-contacting nucleus and the hippocampus. By injecting cholera toxin B subunit (CB) - saporin (SAP) into the lateral ventricle of animals to exclusively damage this nucleus, a mature CSF-contacting nucleus-deficient model animal was established. Then, the changes in learning and memory behaviors in animals with "damage" or "compensation" after damage to the CSF-contacting nucleus were studied. The results showed that learning and memory abilities in animals decreased significantly after the destruction of the CSF-contacting nucleus, accompanied by a decrease in 5-HT concentrations in hippocampus. However, after compensating for 5-HT in the hippocampus continuously, the learning and memory abilities of the animals were significantly improved. This study suggests that the CSF-contacting nucleus may participate in the regulation of learning and memory through direct synaptic connections with the hippocampus.