Current Biology
December 1, 2023
Nicholas Kolbman, Tiecheng Liu, Peter Guzzo et al.
21 citations
A single intravenous dose of psilocybin reduces mechanical hypersensitivity for 28 days in a rat model of formalin-induced chronic pain, suggesting potential for treating chronic pain conditions. The study addresses a gap in research on psilocybin's effectiveness for chronic pain, as prior work focused on psychiatric disorders and substance abuse. No systematic investigation had previously examined psilocybin's impact on chronic pain indices.
Translational Psychiatry
March 25, 2025
Brian H Silverstein, Nicholas Kolbman, Amanda Nelson et al.
8 citations
Psilocybin alters brain network organization in rats in a dose-dependent manner. Using electroencephalography from 27 cortical sites in 12 rats, the study found that psilocybin disrupted theta-gamma coupling, increased frontal high gamma connectivity and network density, and increased posterior theta connectivity and density. Medium gamma frontoparietal connectivity and behavioral activity showed an inverted-U relationship with dose. These results suggest that high-frequency network organization, decoupled from local theta-phase, may be a key signature of psilocybin-induced altered states of consciousness.
Sleep
May 26, 2025
Alejandra Mondino, Amir Jadidian, Brandon A Toth et al.
4 citations
The preoptic area of the hypothalamus, long thought to only promote sleep, contains glutamatergic neurons (MLPO_VGLUT2) that actually drive wakefulness and suppress REM sleep. Using fiber photometry in mice, these neurons were highly active during REM sleep, wakefulness, and brief arousals, but minimally active during non-REM sleep. Chemogenetic stimulation of MLPO_VGLUT2 inhibited REM sleep onset, independent of non-REM fragmentation caused by hypothermia, and blocked the REM sleep rebound normally seen after total sleep deprivation. Chemogenetic inhibition increased REM sleep time only during the light phase. Mapping showed these neurons project to brain regions that promote wakefulness and inhibit REM sleep. The authors conclude that MLPO_VGLUT2 powerfully suppress REM sleep, and their overactivation disrupts REM recovery.
bioRxiv (Cold Spring Harbor Laboratory)
February 12, 2024
Brian H Silverstein, Nicholas Kolbman, Amanda Nelson et al.
3 citations
preprint
Psilocybin disrupts the coupling between theta and gamma brain waves in rats and reorganizes brain networks in a dose-dependent manner. Using 27 electrodes across the cortex, the study found that psilocybin increased frontal high gamma connectivity and posterior theta connectivity, as well as network density in those regions. Medium gamma frontoparietal connectivity showed a nonlinear relationship with dose. Theta-gamma phase-amplitude coupling was disrupted. These changes suggest that high-frequency network organization, decoupled from local theta-phase, may be a signature of the altered state of consciousness induced by psilocybin.
bioRxiv (Cold Spring Harbor Laboratory)
October 14, 2025
Nicholas Kolbman, Amanda Nelson, Rachel Summerfield et al.
1 citation
preprint
Psilocybin and DMT, two serotonergic psychedelics, delay the onset of slow-wave sleep and REM sleep, and cause a short-lasting increase in wakefulness and decrease in slow-wave sleep in rats. Psilocybin also reduces REM sleep, decreases theta power and coherence, and increases high gamma power and coherence during wake and slow-wave sleep, as well as increasing high gamma coherence during REM sleep. DMT increases gamma coherence only during wakefulness. The enhanced high gamma functional connectivity suggests that psychedelic-induced changes in neural dynamics can occur independently of arousal states.
Physiology
May 1, 2024
Rachel Summerfield, Trent Groenhout, Tiecheng Liu et al.
Intravenous DMT, a psychedelic, increases wakefulness and reduces slow-wave sleep in rats during the first three hours after administration, with a delay in the onset of rapid eye movement sleep. Low (3.75 mg/kg) and high (7.5 mg/kg) doses both produced these effects, while time spent in REM sleep during the light period was unaffected. The findings align with previous reports on serotonergic psychedelics and wakefulness.
bioRxiv (Cold Spring Harbor Laboratory)
August 28, 2023
Nicholas Kolbman, Tiecheng Liu, Peter R. Guzzo et al.
preprint
A single intravenous dose of psilocybin (1 mg/kg or 10 mg/kg) reduced mechanical hypersensitivity in rats for 28 days after formalin-induced chronic pain, but had only a limited effect on thermal hyperalgesia. Formalin injection caused thermal hyperalgesia and bilateral mechanical hypersensitivity in all rats. Psilocybin significantly attenuated the mechanical hypersensitivity throughout the 28-day testing period, while thermal hyperalgesia was reduced only on days 1, 3, 5, and 21. These results suggest psilocybin may have potential for treating chronic pain, though its effects on different pain types vary.