The Classic, or Serotonergic, Psychedelics

DMT, LSD, Psilocybin, and Mescaline: these classic psychedelics work via serotonin 5-HT2A receptor agonism. These receptors are widely distributed across the central nervous system with high concentrations in visual cortex and association areas of the cerebral cortex. Psychedelic activation of 5-HT2AR's leads to desynchronization of oscillatory activity, disintegration of intrinsic integrity in the Default Mode Network (DMN), increased between-network global functional connectivity, and expanded signal diversity. These dynamics help us to understand the unique behavioral phenomenology, perception changes, and altered states of consciousness associated with classic psychedelics.

To read more check out this awesome article: Classic psychedelics: An integrative review of epidemiology, therapeutics, mystical experience, and brain network function.