Both 2C-B and psilocybin acutely loosen the usual boundaries between brain networks. In healthy volunteers, they reduce cohesion within networks such as visual and default mode systems, while increasing connections between networks and between cortical and subcortical regions. Signal complexity also rises, indicating more diverse and less predictable activity.
Where they differ: psilocybin tends to produce broader and stronger cross-network changes, whereas 2C-B shows relatively greater increases in some transmodal links, for example between default mode and frontoparietal areas. Participants also reported psilocybin as more intense or dysphoric on average, despite similar scan-time intensity.
Mechanistically, the spatial pattern of changes aligns for both drugs with regions rich in 5-HT2A receptors. Differences between 2C-B and psilocybin may also relate to 5-HT1A and dopamine transporter distributions, though these associations are correlational.
These results come from a small, double-blind, placebo-controlled crossover study in healthy volunteers using 7T resting-state fMRI and are not evidence of therapeutic effects. For details, see the Molecular Psychiatry report.
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