Neuroimage
May 25, 2019
Louis-David Lord, Paul Expert, Selen Atasoy et al.
249 citations
Brain function can be understood as the exploration of a repertoire of metastable connectivity patterns that underlie different mental processes. Intravenous infusion of psilocybin rapidly modulates how the brain dynamically explores these resting-state networks. Using a data-driven approach focused on the leading eigenvector of BOLD phase coherence at single-TR resolution, recurrent BOLD phase-locking patterns were assessed pre- and post-infusion. A frontoparietal subsystem pattern was strongly destabilized after psilocybin, while a pattern characterized by global BOLD phase coherence became more probable. These results demonstrate network-specific neuromodulation by psilocybin, bridging molecular pharmacodynamics and whole-brain network dynamics.
Neuroimage
March 8, 2020
Manesh Girn, Caitlin Mills, Leor Roseman et al.
139 citations
Creativity involves alternating between generating ideas and evaluating them. A refined Dynamic Framework of Thought describes creative generation not as one mental state but as a product of many varying states. The psychedelic state is proposed as a mental state with high potential for facilitating creative generation, making psychedelic substances useful experimental tools for studying the neuroscience of creativity.
Neuroimage
April 25, 2022
Manesh Girn, Leor Roseman, Boris Bernhardt et al.
112 citations
LSD and psilocybin flatten the brain's normal hierarchical organization, reducing the functional separation between sensory and higher-order networks and increasing cross-talk between them. Analyzing two resting-state fMRI datasets, the principal gradient of cortical connectivity—which normally runs from basic sensory areas to complex association regions—was significantly compressed under both drugs compared to placebo. This flattening was driven by decreased specialization at both ends of the hierarchy: default mode and frontoparietal networks at the top, and somatomotor networks at the bottom. The findings support a proposed mechanistic model of the psychedelic state and demonstrate that macroscale connectivity gradients can be acutely altered by a pharmacological intervention.
Neuroimage
December 17, 2019
Lionel Barnett, Suresh D. Muthukumaraswamy, Robin L. Carhart-Harris et al.
88 citations
The psychedelic state involves a breakdown in patterns of information flow in the brain. Using MEG recordings, researchers measured functional connectivity after administration of LSD, psilocybin, and low-dose ketamine, and compared them with the non-psychedelic drug tiagabine. All three psychedelics decreased directed functional connectivity (information flow) throughout the brain, as measured by Granger causality. For LSD, this decrease was coupled with an increase in undirected functional connectivity (correlation and coherence), a surprising opposite movement that highlights the importance of comparing multiple measures of functional connectivity in neuroimaging data.
Neuroimage
June 24, 2019
Carla Pallavicini, Martina G. Vilas, Mirta Villarreal et al.
66 citations
Classic serotonergic psychedelics and dissociative drugs like ketamine produce overlapping subjective effects despite different pharmacological mechanisms. Using source-localized magnetoencephalography, researchers found that LSD, psilocybin, and ketamine all caused widespread broadband reductions in spectral power. Machine learning classifiers trained on one pair of drugs could identify the third, confirming similarity. Functional connectivity analysis revealed decreases in low alpha and theta bands specific to LSD and psilocybin, linked to 5-HT2A agonism, while low beta band decreases were common to all three drugs. These findings quantify shared large-scale brain activity patterns across drug classes and suggest that beta band decoupling is an effect shared between NMDA antagonists and 5-HT2A agonists.
Neuroimage
January 29, 2021
Beatrice M. Jobst, Selen Atasoy, Adrián Ponce-Alvarez et al.
37 citations
After taking LSD, the brain's dynamics become less stable and more diverse in response to perturbations. Using a whole-brain computational model fitted to fMRI data from individuals under LSD or placebo, researchers simulated external disruptions to different brain regions. They measured recovery time with the Perturbational Integration Latency Index (PILI). Globally, LSD caused consistently higher PILI values, indicating a shift further from stable equilibrium. Locally, the largest differences appeared in the limbic, visual, and default mode networks. LSD also increased variability of PILI across brain regions, suggesting greater response diversity. These findings reveal brain-wide dynamical changes underlying the psychedelic state and suggest potential clinical applications for psychiatric disorders.
Neuroimage
December 14, 2024
Avijit Chowdhury, Marta Bianciardi, Eric Chapdelaine et al.
14 citations
Advanced meditation states known as Jhanas, achieved through concentration absorption, are associated with distinct patterns of brain activity and subjective experience. In an intensive case study of an experienced meditator, each Jhana state showed unique neural signatures, including changes in gamma power, alpha desynchronization, and connectivity between frontal and parietal regions. These findings suggest that Jhana states are not merely variations of ordinary mindfulness but involve specific, reproducible neurophenomenological profiles. The work demonstrates that deep meditative absorption can be systematically studied using multimodal brain imaging and first-person reports, providing a foundation for understanding altered states of consciousness.
Neuroimage
May 4, 2023
Andrew Gaddis, Daniel E. Lidstone, Mary Beth Nebel et al.
correction
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