Unraveling the roles of cerebrospinal fluid-contacting neurons

Abstract

Sensory neurons previously shown to optimize speed and balance in fish by providing information about the curvature of the spine show similar morphology and connectivity in mice.

Keywords: PKD2L1; cerebrospinal fluid; cerebrospinal fluid-contacting neuron; interoception; locomotion; mechanosensation; mouse; neural circuit; neuroscience; proprioception; spinal cord.

Figure 1.. Cerebrospinal-contacting neurons share common functional morphology and neuronal targets in the spinal cord of mice and fish, where they help to optimize balance and locomotion.

Cerebrospinal-contacting neurons (CSF-cNs; pink) in the central canal (green) of the spinal cord (dark grey) improve balance and locomotion by sensing mechanical stimuli and sending this information via their axons (black lines) to neurons that control motor outputs. (Left) As described in Wu et al., 2021, in zebrafish, the CSF-cNs connect to various groups of spinal cord cells involved in locomotion, such as excitatory premotor and sensory V0-v and V2a interneurons (blue circles), fast and slow motor neurons (white circles with black outline; bottom), reticulospinal neurons (which relay locomotion-initiating signals from the brain) as well as serotoninergic neurons acting as neuromodulators. Some of the CSF-cNs also project onto groups of cells in the hindbrain, such as occipital motor neurons. Finally, CSF-cNs project onto large sensory interneurons which likely convey information of a corollary discharge (the process by which the brain can be informed of impending movement) back to the hindbrain. (Right) Nakamura et al. showed that, similar to fish, the axons of the CSF-cNs in mice project to motor neurons and pre-motor excitatory interneurons, but also onto other CSF-cNs. This is in agreement with another recently published study (Gerstmann et al., 2022).