medRxiv
September 29, 2019
Lorenzo Pasquini, Fernanda Palhano-Fontes, Draulio B. Araujo
24 citations
preprint
One day after a single session with the psychedelic ayahuasca, connectivity within and between brain networks that support interoception, emotion, and self-related thought is altered compared to placebo. In a randomized trial with 22 participants receiving ayahuasca and 21 receiving placebo, the ayahuasca group showed increased connectivity within the salience network, decreased connectivity within the default mode network, and increased connectivity between these two networks. Primary sensory networks were not affected. These connectivity changes correlated with acute subjective effects such as altered body awareness, volition, and affect. The findings suggest that ayahuasca induces subacute functional reorganization of higher-order cognitive brain networks.
Research square
March 8, 2024
Hannes Kettner, Leor Roseman, Adam Gazzaley et al.
5 citations
Older adults (age 60+) who participated in a guided psychedelic group retreat showed significant improvements in well-being, with larger gains among those with a prior psychiatric diagnosis. Compared to younger adults, older adults experienced weaker acute psychedelic effects, and these effects did not predict well-being changes. Instead, a sense of communitas—the relational or social connection during the group session—predicted well-being improvements in older adults, suggesting that the social context of psychedelic therapy may be especially important for this age group.
bioRxiv (Cold Spring Harbor Laboratory)
November 7, 2024
Lorenzo Pasquini, Jakub Vohryzek, Anira Escrichs et al.
4 citations
preprint
Psilocybin induces fast and sustained improvements in mental well-being, yet its long-term mechanisms are not fully understood. Four weeks after a full dose, fronto-striatal-thalamic (FST) circuitry—involved in goal-directed behavior and motivation—shows increased dynamic activity and flexibility in healthy volunteers. Computational modeling indicates that reduced structural constraints on functional dynamics cause this increased flexibility. Long-term changes include increased bottom-up and reduced top-down information flow, mediated by serotonergic (5-HT2A) and dopaminergic (D2) receptor systems. This functional re-organization of FST circuits may represent a common mechanism underlying clinical improvements across neuropsychiatric disorders such as substance abuse, major depression, and anorexia.
bioRxiv : the preprint server for biology
August 12, 2024
Lorenzo Pasquini, Alexander J Simon, Courtney L Gallen et al.
4 citations
preprint
The psychedelic DMT rapidly alters consciousness, producing physical transcendence, vivid auditory distortions, and visual imagery. Using simultaneous fMRI and EKG data from 14 healthy volunteers before, during, and after intravenous DMT (versus placebo), a brain substate emerged immediately after injection characterized by deactivations in the hippocampus and medial parietal cortex alongside increased superior temporal lobe activity. Hippocampal and medial parietal deactivations correlated with disruptions in the sense of time, space, and self-referential processes, reflecting a deconstruction of ordinary consciousness. Superior temporal lobe activations correlated with audio/visual hallucinations and the experience of "entities.
Imaging Neuroscience
April 16, 2025
Lorenzo Pasquini, Alexander J. Simon, Courtney L. Gallen et al.
1 citation
DMT rapidly induces a short-lasting altered state of consciousness marked by physical transcendence, vivid auditory distortions, and visual imagery. Using simultaneous fMRI and EKG data from 14 healthy volunteers before, during, and after intravenous DMT or placebo, a brain substate emerged immediately after DMT injection, characterized by deactivations in the hippocampus and medial parietal cortex and increased activity in the superior temporal lobe. Hippocampal and medial parietal deactivations correlated with altered sense of time, space, and self-referential processes, reflecting a deconstruction of ordinary consciousness. Superior temporal lobe activations correlated with audio/visual hallucinations and the experience of "entities.
bioRxiv (Cold Spring Harbor Laboratory)
March 10, 2025
Shaun K.l. Quah, Cameron Glick, Leor Roseman et al.
preprint
People with major depression who responded to either psilocybin or escitalopram showed distinct changes in brain network connectivity compared to non-responders. Responders had increased linear connectivity within the ventral attention network and greater nonlinear connectivity within the default mode and ventral attention networks. Psilocybin responders showed enhanced coordination between higher-order networks, while escitalopram responders showed reduced connectivity within networks linked to self-referential thought and salience processing. These patterns suggest the two antidepressants work through different mechanisms, with nonlinear connectivity analyses revealing effects not captured by traditional linear measures.