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The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs
Frontiers | The entropic brain: a theory of conscious states informed by neuroimaging research with psychedelic drugs | Frontiers in Human Neuroscience

Entropy is a dimensionless quantity that is used for measuring uncertainty about the state of a system but it can also imply physical qualities, where high entropy is synonymous with high disorder. Entropy is applied here in the context of states of consciousness and their associated neurodynamics, with a particular focus on the psychedelic state. The psychedelic state is considered an exemplar of a primitive or primary state of consciousness that preceded the development of modern, adult, human, normal waking consciousness......................

Based on neuroimaging data with psilocybin, a classic psychedelic drug, it is argued that the defining feature of “primary states” is elevated entropy in certain aspects of brain function, such as the repertoire of functional connectivity motifs that form and fragment across time.

Psilocybin
https://en.wikipedia.org/wiki/Psilocybin

Psilocybin[nb 1] (/ˌsɪləˈsaɪbɪn/ sil-ə-sy-bin) is a naturally occurring psychedelic compound produced by more than 200 species of mushrooms, collectively known as psilocybin mushrooms.