Proceedings of the National Academy of Sciences of the United States of America
March 28, 2023
Christopher Timmermann, Leor Roseman, Sharad Haridas et al.
217 citations
Intravenous DMT, a potent psychedelic and serotonin 2A receptor agonist, profoundly alters brain function in healthy volunteers. In a placebo-controlled study with 20 participants, multimodal neuroimaging (EEG-fMRI) showed that DMT robustly increases global functional connectivity, disrupts and desegregates brain networks, and compresses the principal cortical gradient. These changes overlapped with brain regions rich in serotonin 2A receptors and associated with human-specific psychological functions. EEG and fMRI measures correlated, linking neurophysiological changes to network-level effects. The findings indicate DMT predominantly acts on the brain's transmodal association cortex, the evolutionarily recent area tied to advanced cognition and high 5-HT2A receptor density.
Elife
October 12, 2020
Andrea Alamia, Christopher Timmermann, David J Nutt et al.
86 citations
The psychedelic drug DMT rapidly induces a highly immersive state of consciousness with vivid visual imagery. In a study of participants who received DMT or placebo (saline) while keeping their eyes closed, brain electrical activity showed a pattern of cortical travelling waves similar to that normally seen during visual stimulation. The typical alpha-brainwave rhythms of eyes-closed rest were significantly reduced, while forward-directed waves from lower to higher brain regions increased. These findings support the idea that psychedelics reduce the brain's reliance on prior expectations, shifting the balance from top-down to bottom-up information processing, which may be a key mechanism underlying altered states of consciousness.
bioRxiv (Cold Spring Harbor Laboratory)
May 8, 2020
Andrea Alamia, Christopher Timmermann, Rufin Vanrullen et al.
25 citations
preprint
The psychedelic drug DMT rapidly induces an immersive conscious state with vivid visual imagery. EEG recordings showed that DMT alters cortical traveling waves: the typical alpha-band backward wave of eyes-closed rest decreased, while a forward wave similar to that seen during visual stimulation increased. This supports a model where psychedelics reduce the precision-weighting of prior expectations, shifting the balance from top-down to bottom-up information flow. The findings suggest that backward traveling waves are correlates of precision weighting and that reduced backward and increased forward waves are a mechanistic principle of psychedelic-induced altered states.
Elife
November 9, 2020
Andrea Alamia, Christopher Timmermann, David J Nutt et al.
7 citations
correction
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