How can I find literature about the connection between proprioception and thinking?
Two major terms:

"Spatial Representation":

of pitch height (lower/higher):

https://www.sciencedirect.com/science/article/pii/S0010027705000260

emotions (down/up):

https://www.tandfonline.com/doi/abs/10.1080/02699930500347794

"Spatial Analogy":
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5256459/

Some papers argue that even time has strong spatial representation in it:
https://www.sciencedirect.com/science/article/pii/S001002770700087X