And taken to the extreme by groups like the Monroe Institute and their experiments with the U.S. D.O.D. on altered states of consciousness they state as a result of their method of synchronizing brainwaves between the two hemispheres akin to various forms of meditation.
For the rabbit-holers:
https://en.wikipedia.org/wiki/Robert_Monroe
Related: https://www.cia.gov/readingroom/docs/CIA-RDP96-00788R0017002...
Also related, recording: https://archive.org/details/monroe-institute-explorer-series...