Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism
February 26, 2025
Kristian Larsen, Ulrich Lindberg, Brice Ozenne et al.
9 citations
Psilocybin, the active compound in magic mushrooms, reduces blood flow in the brain. In a study of 28 healthy volunteers, psilocybin decreased cerebral blood flow by about 11.6% at peak effect, while the serotonin blocker ketanserin had no significant effect. Psilocybin also constricted the internal carotid artery by 10.5%, whereas ketanserin did not. These findings suggest that psilocybin's effects on brain blood flow involve the serotonin 2A receptor and may help explain its therapeutic potential for conditions like depression.
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism
June 1, 2026
Klemens Egger, Robert Bozsak, Helena D Aicher et al.
A psychedelic dose of DMT combined with harmine (mimicking ayahuasca) globally increased cerebral glucose metabolism by 12.5% in 14 healthy males, as measured by FDG-PET scans during peak drug effects. Widespread cortical increases appeared in higher-order brain networks. Global glucose metabolism correlated positively with harmine plasma levels but not with DMT levels or subjective intensity. This recapitulates a classic finding for psilocybin, suggesting a potential metabolic signature of the psychedelic state.
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism
April 1, 2026
Daphne E Boucherie, Liesbeth Reneman, Jan Booij et al.
A new method combining two brain imaging techniques—pharmacological MRI and pharmacological MRS—was tested in 32 healthy adults given S-ketamine or placebo. S-ketamine caused strong blood-flow changes in frontal, cingulate, and insular brain regions, which matched patterns of glutamate and opioid receptors and correlated with participants' reports of dissociation. These blood-flow changes occurred alongside increases in brain glutamate and lactate, especially at higher doses. Combining both imaging methods improved the ability to predict whether a person had received placebo, a low dose, or a high dose of S-ketamine. The findings show that simultaneously measuring blood flow and brain chemistry provides complementary insights into how drugs affect the brain.
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism
March 21, 2026
Claudio Agnorelli, Joseph Peill, Gabriela Sawicka et al.
A single intravenous dose of ketamine (1 mg/kg) in eleven healthy men altered brain chemistry and connectivity days later. Glutamate levels rose in the anterior cingulate cortex (ACC). Functional coupling between the ACC and the dorsolateral prefrontal cortex decreased, while coupling between the ACC and the amygdala increased. Participants whose PET scans indicated increased synaptic plasticity showed reduced intrinsic activity in default mode network (DMN) regions. The findings suggest the DMN is a central hub where ketamine may reshape brain hierarchies, offering clues to its therapeutic mechanisms.