Elife
March 2, 2021
Balázs Szigeti, Laura Kärtner, Allan Blemings et al.
192 citations
A self-blinding citizen science trial with 191 participants tested whether microdosing psychedelics produces psychological benefits beyond a placebo. All psychological outcomes improved from baseline to after the four-week dose period in the microdose group, but the placebo group also improved, and no significant between-group differences were observed. Small, significant differences in acute measures (emotional state, drug intensity, mood, energy, creativity) and post-acute anxiety appeared, but these could be explained by participants breaking blind. The findings suggest that anecdotal benefits of microdosing can be explained by the placebo effect.
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.
Elife
November 9, 2020
Andrea Alamia, Christopher Timmermann, David J Nutt et al.
7 citations
correction
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Elife
April 21, 2026
Classical psychedelics produce visual hallucinations that are coherent at a low level but dream-like at a high level, yet no concrete mechanistic model explains these effects while remaining consistent with known pharmacology. The authors propose the 'oneirogen hypothesis': psychedelics induce neural activity states similar to dreaming. They simulate this by manipulating neural network models trained with the Wake-Sleep algorithm, partially shifting the model to a 'Sleep' state with greater top-down influence, mimicking effects on apical dendrites. This captures observed phenomena like hallucinations, increased stimulus-conditioned variability, and synaptic plasticity. The work offers testable predictions to validate the hypothesis.
Elife
August 21, 2025
Criterion shifts—changes in how people decide whether they have seen something—can distort neural measures of consciousness, causing simultaneous over- or under-estimation of both conscious and unconscious processing. While it was already known that subjective reports are vulnerable to such biases, new simulations and empirical work show that these effects have concrete consequences when analyzing real brain data. The authors argue that their findings are novel and that the experimental manipulations they used are not unrealistic compared to natural variations across experiments.