Acute psilocybin effects on CBF and ICA diameter

This figure shows the acute effects of psilocybin on cerebral blood flow and internal carotid artery diameter in healthy human participants. Whole-brain cerebral blood flow was measured using pseudo-continuous arterial spin labelling MRI at baseline, during the peak and late phases following psilocybin administration (0.2–0.3 mg/kg, N = 28). Cerebral blood flow maps illustrate widespread cortical reductions at peak plasma psilocin levels. Plasma psilocin concentrations were negatively associated with both whole-brain cerebral blood flow and internal carotid artery diameter, indicating dose-dependent effects. MRI acquisition, preprocessing, and statistical modelling procedures are described in detail in Larsen et al. (Journal of Cerebral Blood Flow & Metabolism, 2025).