Be careful reading through Psychedelic Information Theory - it's an odd mix of pretty accurate information about the pharmacology of psychedelics, and a lot of unsubstantiated speculation. We know very little about how to make the leap from the cell-level to the cognitive/perceptual level, and the author fills that gap in with a lot of stuff that, as a neuroscientist, seems specious at best.
There's been a lot of work into the neurological correlates of the psychedelic experience since this was published - if you're interested in this kind of thing, look into the works of Carhart-Harris - "Homological Scaffolds of Brain Function Networks" (which should still be available for free) is probably the biggest breakthrough in the field of psychedelic neuroscience since the discovery of the 5-HT2Ar
Blessings
~ND
"There are many paths up the same mountain."