A, Effects of psilocybin and ketanserin on group-averaged event-related potential waveforms for the three parieto-occipital ROIs. Placebo + placebo (black), placebo + psilocybin (red), ketanserin + placebo (blue), and ketanserin + psilocybin (green). B, Correlation between the psilocybin-induced reduction of N170 amplitudes and the psilocybin-induced perceptual visual alterations as measured by the main scales (B1) and subscales (B2) of the 5D-ASC questionnaire.