Serotonin and psilocybin activate 5-HT1B receptors to suppress cortical signaling through the claustrum
Nature Communications August 19, 2025 Maxwell B. Madden, Chloe Schaefgen, Binita Vedak et al. 4 citations
Serotonin activates 5-HT1B receptors on anterior cingulate cortex inputs to the claustrum, suppressing signaling to parietal association cortex-projecting claustrum neurons. Psilocybin, metabolized to the serotonin receptor agonist psilocin, similarly activates these presynaptic 5-HT1B receptors, reducing cortical signaling through the claustrum. This gain-control mechanism may be directly targeted by psilocybin to modulate downstream cortical network states, offering insight into how the classic psychedelic disrupts widespread brain activity.