Psychedelic experiences are highly sensitive to the individual’s mindset and environment. So it’s not easy to generalize lab findings to natural settings.
Research shows that setting impacts the experience, with more positive outcomes linked to well-prepared environments.
The study aims to get quality EEG data without disturbing the psychedelic experience. DMT’s short duration made it a good choice for this study. It allowed the authors to look at both usual effects of the drug and the impact of the environment.
A total of 29 participants who had previous experience with DMT joined the study. They underwent a thorough assessment procedure to make sure they are a fit for the experiment.
To make them comfortable, scientists let them choose their own setting. These include music, lighting and other factors.
Once fitted with the EEG system, participants either took DMT on their own, or had help from the facilitator. Collecting EEG data happened before DMT inhalation, and during the effect of psychedelics.
Once the participant went back to baseline the recording was ended. During the experience, participants had their eyes closed, relaxed and sat upright.
To assess participants’ experience before and after DMT, they filled out many questionnaires. The answers gave insight into their subjective experience of the setting and psychedelic effect. Authors could also assess participants’ (mind)set they brought to the experiment.
(a) A radar plot showing subjective scores for some questionnaire forms. They include: 5D Altered States of Consciousness Scale (5D-ASC), Mystical Experience Questionnaire (MEQ-30), Near-Death Experience (NDE) and more. (b) Pearson’s linear correlation between different scores in the listed questionnaires. Threshold is at p<0.05 significance level, where the greyed out correlations didn’t meet the criteria.Findings from “set”, “setting” and “psychedelic experience” assessment
Participants reported subjective effects that matched earlier studies. Significant changes were seen in “visionary restructuralization,” “oceanic boundlessness”, and “anxious ego dissolution.”
Of all the participants, 37% met the criteria for a complete mystical experience. This rate falls between those reported for psilocybin and LSD. Scientists didn’t find the expected link between openness and psychedelic experiences. This link is well-documented for other psychedelics.
What they found was an increase in agreeableness, which might relate to the social context of the experience.
Significant decrease in alpha band power immediately after DMT intake
Before administering DMT, EEG was recorded during baseline. During this period participants had their eyes closed and opened for 5 minutes.
Let’s look into the power of different EEG frequency bands, in 3 conditions.
(a) Alpha peak at around 10Hz is significantly attenuated (p < 0.05) for the DMT condition, compared to baseline. (b) Topographical maps for the t-values resulting from comparing DMT vs eyes closed per frequency band. Decrease in alpha activity is significant across electrode sites. Also, we can observe significant increase in delta and gamma bands.Scientists further analyzed changes in alpha across time, during DMT effect. They subtracted the eyes-closed condition from DMT condition.
(a) We can see a drop in alpha power immediately after DMT use, which returned to baseline after about 7 minutes.
(c) Only alpha decrease was significant across different power bands. The red horizontal bar indicates the threshold for statistical significance. This significance was present until 3 min after DMT onset.
This pattern differed from earlier studies, as the effect of DMT wore off a bit earlier then expected. This is likely due to differences in how DMT was given and the used doses.
Potential EEG markers of mystical-type experiences in natural settings
When correlating subjective scores and different frequency bands, only beta and gamma bands gave significant results.
(a) Beta and gamma power were averaged across different brain regions. Greyed out correlations are not statistically significant. (b) Scalp distribution of correlation coefficients, where significant electrodes are marked in white.Increased gamma power under DMT correlates with many items from the 5D-ASC, NDE, and MEQ-30 scales. These items reflect aspects of mystical-type experiences.
These gamma oscillations could relate to the binding of information during peak experiences.
Increased signal diversity under DMT’s effects
To analyze synchronization and de-synchronization between channels, authors included coherence and metastability analysis. They compared them in 2 conditions – DMT and eyes-closed.
Signal complexity is also compared for different electrodes across conditions.
Changes in coherence (C), metastability (K), and signal complexity following psychedelics. (a) Violin plots for C and K computed from the DMT and eyes-closed conditions. (b) Signal complexity t-value maps for DMT vs eyes-closed and eyes-open vs eyes-closed. Electrodes in white represent significant differences with p<0.05.There’s a decrease of coherence and stability in the alpha band, while with gamma we see an increase. This suggest that gamma hyper-synchrony might show the increased information binding seen in psychedelic-induced experiences.
The study showed feasibility of getting high-quality neural recordings during psychedelic experiences. It also highlights the importance of considering contextual factors in psychedelic research. You can find the original study on this link.
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