Psychedelic drugs like LSD and psilocybin may treat neuropsychiatric disorders by dose-dependently altering the brain's functional hierarchy—the organization of neural activity across regions. Using a turbulence framework that measures local synchronization (vorticity) in both space and time, researchers found that both drugs produce consistent and distinct effects, particularly compressing the default mode network, a higher-level network. These findings support the hypothesis that psychedelics modulate the functional hierarchy and provide a quantitative comparison of how LSD and psilocybin change brain dynamics, with implications for therapeutic use.
Functional connectomes become more idiosyncratic under psilocybin, with greater dissimilarity between individuals than under placebo. While idiosyncratic features in placebo subjects appear mainly in the frontoparietal network, under psilocybin they concentrate in the default mode network (DMN). A DMN-focused pattern predicts subjective psilocybin experience, marked by reduced within-DMN and DMN-limbic connectivity and increased connectivity between the DMN and attentional systems. These findings link psilocybin's brain effects to subjective experience and demonstrate the value of brain-fingerprinting in pharmacological neuroimaging.
Alpha and theta brain rhythms have been linked to mindfulness, but connecting brain activity to subjective experience is difficult. This study used network analysis on data from 16 novices who completed up to 24 sessions of focused attention and open monitoring meditation, with EEG and self-reported mindfulness collected. Distinct network structures emerged for each practice, supporting their theoretical differences. Shared features included strong autoregressive effects for mindfulness—consistent with skill learning—and opposing influences of frontal versus posterior alpha power. The results challenge simple interpretations of meditation-related EEG, suggesting the functional meaning of neural activity depends on the specific practice and training stage.