DMT On The Brain

Human brain effects of DMT assessed via EEG-fMRI - Clinical trials of psychedelic therapy for the treatment of a variety of mental health conditions have yielded consistently promising safety and efficacy findings. The signature psychological effects of the so-called classic psychedelics are initiated via agonism at the serotonin 2A receptor (5-HT2AR). A wealth of convergent evidence suggests that 5-HT2A receptor agonism is the trigger event in psychedelics’ therapeutic action, likely initiating processes of cortical plasticity that are exploited via adjunctive psychological support.

Most human research with pure DMT has involved an intravenous mode of administration. Given this way, the drug has a rapid action—peaking at ~3 min and subsiding at ~15 min; ideal for examining rapid changes in brain function associated with a rapid transition into, and back from, a highly altered quality of waking consciousness. Accordingly, human functional neuroimaging with DMT offers a unique scientific opportunity for advancing our understanding of the neurobiology of conscious states.

Results from previous functional MRI (fMRI) studies assessing the brain effects of psychedelics have revealed decreased within-network functional connectivity (FC) or 'integrity', increased between-network FC or decreased 'segregation', a larger repertoire of brain connectivity profiles, a globally hyperconnected brain state, freer transitions between brain states, and a reduction of its principal sensory-association cortex gradient. Importantly, these studies broadly converge on the action of psychedelics on the transmodal association cortex pole (or 'TOP') of the human brain. The TOP sits at the upper end of a hierarchical gradient of cortical organization, while unimodal sensory areas sit at the lower end. The TOP is linked to abstract semantic representations, longer temporal windows of information processing, and is relatively more detached from sensory input, while also appearing later in primate cortical expansion and development. These findings suggest that the subjective effects of psychedelics depend on the dysregulation of the association cortices. Evidence from neuroimaging studies also suggests that this cortical dysregulation may result in the disinhibition of 'lower' or evolutionarily and developmentally 'earlier' systems such as the so-called limbic system.

Until the present study, only indirect correlations have been possible between electrophysiological and fMRI functional brain activity recordings done under the effects of a psychedelic; thus, the present study offers an opportunity to simultaneously acquire and then correlate such data, while at the same time leveraging DMT’s short-acting effects. Acquiring electroencephalography (EEG) and fMRI in parallel also enables us to see true neuronal activity (i.e., through the EEG data) rather than having to infer it through a hemodynamic signal [i.e., the fMRI blood oxygen level–dependent (BOLD) signal] that could be confounded by a direct vascular action of the drug. Furthermore, the high temporal resolution of EEG provides reliable means to relate the rhythmic and entropy-related effects induced by a psychedelic with simultaneous changes in brain connectivity captured with fMRI. The inclusion of EEG therefore gives us confidence about the neuronal action of the psychedelic.

In this study, we advance on previous work examining the neural correlates of the psychedelic state by combining fMRI and electroencephalography (EEG) in a simultaneous recording paradigm in a resting-state condition. Intravenous DMT (versus placebo) was administered to healthy volunteers during eyes-closed, resting-state conditions. This approach offers an important advancement because it enables the direct observation of changes in neuronal activity (EEG) in parallel with indirect changes seen through the fMRI blood oxygen level–dependent (BOLD) signal. Further, the EEG-fMRI combination overcomes each modality’s bounds on temporal or spatial resolution—enabling the collection of the most comprehensive information possible on brain activity via noninvasive contemporary human functional neuroimaging.

This study was funded via a donation by Patrick Vernon. The Beckley Foundation mediated Patrick Vernon’s support. Christopher Timmermann (C.T.) is funded by Comisión Nacional de Investigación Científica y Tecnológica and Anton Bilton. Robin L. Carhart-Harris (R.C.-H.) was funded by the founding funders of the Centre for Psychedelic Research and is now supported by a Ralph Metzner endowment. We would like to thank Sam Turton, Luigi Espasiano, and Roberta Murphy for providing medical cover during study visits; Ines Violante, Romy Lorenz, and David Carmichael for advice regarding EEG-fMRI data collection and analysis; Albert Busza and Ivana Russo who assisted with MRI data collection; Rick Strassman and Andrew Gallimore who reviewed early versions of the study protocol; and Anton Bilton for intellectual support. Portions of this work were developed from the doctoral thesis of C.T.

DMT Trip Report

So after the first DMT experience @TruelifeStorys decided to go right back in, and he was shown this is a dream. He actually thought he was going to be stuck in the dream state but as it faded he made this video ...

https://www.youtube.com/embed/gRWeGkAtfss