Sensory and Motor Systems
Author: Joselina Berti | Email: jberti@leloir.org.ar
Joselina Berti1°, Guillermo Lanuza1°
1° Fundación Instituto Leloir
Cerebrospinal fluid-contacting neurons (CSF-cNs) are a distinct group of neurons within the spinal cord, which stand out due to their strategic location surrounding the central canal. In zebrafish, they detect spinal curvature during swimming and act as chemosensors of CSF composition. However, how they contribute to CNS circuitry in tetrapods remains unclear. In this work, we characterize the CSF-cNs network in the mouse brain by using Pkd2l1Cre mice to selectively mark the CSF-cN cell bodies, axons and synaptic terminals. We confirm they are present in the central canal in the hindbrain, extending up to the beginning of the fourth ventricle. Their axons project across different brainstem areas, including the hypoglossal (nXII) and Roller nucleus. CSF-cN’ axons wrap around the nXII in a remarkably precise manner, while also innervate the core of the Roller. XII motoneurons modulate tongue movement and are output of the rhythmic network that control breathing. Opposing, Roller nucleus has been poorly studied. The analysis of genetic Synaptophysin-Tom puncta identified that CSF-cNs form profuse GABAergic synapses on ventral motoneurons of the nXII and Dbx1-derived Roller neurons. We hypothesize that CSF-cNs may regulate respiratory activity though these nuclei, according to CSF homeostasis. Altogether, our results describe a brand-new connectivity map of CSF-cN in the mammalian brainstem, which could bring light to unforeseen circuits and regulation of autonomic functions.