Synapse
January 1, 1987
Dean F. Wong, John R. Lever, Paul Hartig et al.
93 citations
A new radioligand, [11C]-MBL, selectively binds to serotonin 5-HT2 receptors in the brain, as shown by in vitro assays (Ki = 0.5 nM) and PET imaging in baboons and seven healthy human volunteers. In humans, highest binding occurred in frontal, temporal, and parietal cortex, with lower levels in caudate and putamen. Blocking with ketanserin confirmed specificity. Frontal cortex-to-cerebellum ratios ranged from 1.7 to 2.7, with older volunteers showing lower ratios, suggesting age-related decline in 5-HT2 receptor density. [11C]-MBL enables in vivo monitoring of these receptors in most human brain regions.
Frontiers in Neuroergonomics
January 20, 2022
Yun Zhou, Frederick S. Barrett, Theresa M. Carbonaro et al.
17 citations
A psychoactive dose of psilocybin (10 mg/70 kg) occupied an average of 39.5% of serotonin 2A receptors in the brains of four healthy volunteers, as measured by PET imaging. The highest occupancy occurred in regions of the default mode network, including the subgenual anterior cingulate and bilateral angular gyri, with values between 63.12% and 74.72%. Individual variability in regional occupancy was marked. These findings support further research into how differences in receptor occupancy relate to psilocybin's acute and lasting effects.
medRxiv
August 24, 2023
Subha Subramanian, Demetrius Perry, Caterina Gratton et al.
14 citations
preprint
Psilocybin disrupts connectivity across cortical networks and subcortical structures, producing more than three-fold greater acute changes in functional networks than methylphenidate. These changes are driven by desynchronization of brain activity across spatial scales, strongest in the default mode network (DMN), which is connected to the anterior hippocampus and thought to create our sense of self. Performing a perceptual task reduces psilocybin-induced network changes, suggesting a neurobiological basis for grounding during psychedelic therapy. Psilocybin induces a persistent decrease in functional connectivity between the anterior hippocampus and cortex (and DMN in particular), lasting for weeks but normalizing after six months. This persistent suppression of hippocampal-DMN connectivity represents a candidate neuroanatomical and mechanistic correlate for psilocybin's pro-plasticity and anti-depressant effects.