Nature
August 1, 2024
Joshua S Siegel, Subha Subramanian, Demetrius Perry et al.
241 citations
A single high dose of psilocybin (25 mg) massively disrupts functional connectivity in the human brain, causing more than threefold greater change than methylphenidate (40 mg). These changes are driven by desynchronization across spatial scales, dissolving network distinctions by reducing correlations within and anticorrelations between networks. The strongest effects occur in the default mode network, which is connected to the anterior hippocampus and is thought to create the sense of space, time, and self. Individual differences in connectivity changes are strongly linked to the subjective psychedelic experience. A persistent decrease in connectivity between the anterior hippocampus and default mode network lasts for weeks, suggesting a neuroanatomical correlate of the therapeutic and proplasticity effects of psychedelics.
NeuroImage
September 1, 2020
Frederick S Barrett, Samuel R Krimmel, Roland R Griffiths et al.
191 citations
Psilocybin, a serotonin 2A receptor partial agonist, alters claustrum function in humans. In 15 healthy participants, psilocybin decreased the amplitude of low-frequency fluctuations and variance of BOLD signal in the left and right claustrum. It also changed functional connectivity: right claustrum connectivity with auditory and default mode networks decreased, while connectivity with the fronto-parietal task control network increased; left claustrum connectivity with the fronto-parietal task control network decreased. Subjective effects predicted these neural changes. The findings provide the first empirical evidence that 5-HT2A receptor signaling significantly modulates claustrum activity, suggesting a role for the claustrum in psilocybin's subjective and therapeutic effects.
Mindfulness
April 1, 2023
Carly A Hunt, Janelle E Letzen, Samuel R Krimmel et al.
9 citations
A secondary analysis of a clinical trial compared a 12-week enhanced mindfulness-based stress reduction course (MBSR+) to stress management for headache in 98 migraine patients. Greater pre-treatment functional connectivity between the ventromedial prefrontal cortex and right nucleus accumbens predicted more meditation practice during MBSR+ and larger reductions in headache frequency. Participants who meditated more showed increased mindfulness and reduced helplessness related to pain, but not improvements in headache frequency, severity, or impact. Increased mindfulness mediated reductions in headache impact but not frequency. The findings suggest mesocorticolimbic system function relates to motivated behavior, and motivation-enhancing interventions might boost meditation engagement.