Research library / Brain imaging study
Human brain effects of DMT assessed via EEG-fMRI
Timmermann C, Roseman L, Haridas S, et al. Proceedings of the National Academy of Sciences 2023;120(13):e2218949120
This study scanned the brains of 20 healthy volunteers with EEG and functional MRI at the same time, before, during and after an intravenous injection of 20 mg DMT, and on a separate occasion after placebo. Under DMT, brain regions communicated more widely across the whole brain and the usual separation between large-scale networks broke down. The regions most affected were the higher-order association areas of the cortex, which also carry the most serotonin 2A receptors, the receptor DMT acts on. The size of these changes tracked how intense people rated the experience. The study is a careful map of what the brain does during a short, intense DMT experience. It does not test whether DMT treats any condition, and with 20 healthy participants it cannot say how patients would respond.
What it found
- fMRI showed robust increases in global functional connectivity under DMT, with brain networks becoming less separated from each other.
- The principal cortical gradient was compressed during the DMT state.
- Maps linking connectivity change to rated intensity matched serotonin 2A receptor maps taken from separate PET data.
- Changes in EEG measures correlated with specific fMRI changes.