A review of dynamic neuroimaging research suggests that the brain's spontaneous activity fluctuates in a non-trivial, structured way, compatible with exploring a discrete repertoire of states. This supports the hypothesis of a dynamic core—a constantly evolving but transiently stable set of coordinated neurons that forms the physical substrate for each conscious experience. Studies indicate that metastability in brain dynamics may underlie this repertoire and that it can be modified during altered states of consciousness. The review proposes that linking metastability to the level of consciousness could lead to a mechanistic understanding of altered states using dynamical systems theory and statistical physics.
The work examines the distinct brainwave patterns produced by two classes of psychoactive drugs: serotonergic psychedelics (such as psilocybin or LSD) and glutamatergic dissociatives (such as ketamine). The authors describe how each drug class generates unique spectral signatures in EEG recordings, reflecting different underlying neural mechanisms. Serotonergic psychedelics are associated with increased gamma power and reduced alpha power, while glutamatergic dissociatives produce increased theta and gamma power. These distinct patterns may serve as biomarkers for the drugs' effects on brain function and consciousness.