Proprioception and immunity?

This is not the first time and, based on recent findings in the literature, I believe it won’t be the last time I write about the non-motor roles of the cerebellum.

Historically speaking, the cerebellum has been considered a motor organ, at the core of the comparison between what is and what is possible.

The cerebellum’s job, in a nutshell, has been to take input from the spinal cord, the vestibular system and the cortex.

It matches what comes from the cortex (demand for movement) with the input from the spinal cord (proprioception) and the vestibular system (balance) as it then fires back to the cortex for actual movement to take place.

On a non-motor front, the cerebellum has been spoken of as a regulator involved in cardiovascular, respiratory and gastro intestinal activities.

Precisely, it has been shown that a lesion of the vestibulocerebellum in rats causes an immunosuppressive effect. The vestibulocerebellum is mostly involved in balance.

Lesions of the fastigial nucleus (most recent nucleus) has been seen to cause an enhancement of T, B, and natural killer cells while lesions on the interposed nucleus can lead to a suppression of these very cells.

The question then is: how is this taking place?

• One hypothesis is the link between the hypothalamus and the cerebellum. Note that this connection is a glutamaergic one (it uses glutamate as a neuromediator). That being said, the presumption is that sympathetic nerves and/or adrenocortical/thyroid hormones are potent candidates for transmission of the immuno regulatory information from the cerebellar IN-hypothalamic glutamaergic projections to immune cells via a relay of the hypothalamus.

https://www.researchgate.net/publication/260367173_Modulation_of_Immune_Function_by_Glutamatergic_Neurons_in_the_Cerebellar_Interposed_Nucleus_via_Hypothalamic_and_Sympathetic_Pathways