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Martin K Madsen

7 papers in the library · 152 citations · publishing 2021-2026

Papers

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Psilocybin's effect on human brain synaptic plasticity.

Translational Psychiatry July 15, 2026 Annette Johansen, Pontus Plavén-sigray, Martin K Madsen et al.

Psychedelics such as psilocybin have been linked to enhanced neuroplasticity and symptom relief in affective disorders, but the neurobiological mechanisms and impact of environmental context remain unclear. Here, we tested whether a single dose of psilocybin (0.3 mg/kg) alters synaptic density in healthy individuals and whether setting-dependent subjective experience shapes this effect. Fifteen...

Effects of psilocybin on sleep quality and brain microstructure in chronic cluster headache.

Journal of psychopharmacology (Oxford, England) May 29, 2026 Kristoffer Brendstrup‐brix, Brice Ozenne, Patrick M. Fisher et al.

Patients with chronic cluster headache (CCH) suffer from poor sleep, which may impact their brain microstructure and parenchymal clearance of waste products. Psilocybin has shown promise for the treatment of CCH and has been linked to increased neuroplasticity with possible influences on brain microstructure. To investigate the effects of psilocybin on sleep, brain water diffusivity, and...

Psilocybin acutely reduces low-frequency BOLD power and frequency-specific connectivity

bioRxiv April 13, 2026 Anders S. Olsen, Kristian Larsen, Drummond E. Mcculloch et al.

Abstract Psilocybin and other serotonergic drugs acutely alter human brain function and large-scale connectivity as measured with BOLD fMRI, but whether these effects are frequency-specific remains unknown. We applied multitaper spectral and cross-spectral analyses to resting-state fMRI data from 28 healthy volunteers scanned multiple times acutely following oral psilocybin administration (0.2...

Acute psilocybin and ketanserin effects on cerebral blood flow: 5-HT2AR neuromodulation in healthy humans.

Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism February 26, 2025 Kristian Larsen, Ulrich Lindberg, Brice Ozenne et al. 9 citations

Psilocin, the active metabolite of psilocybin, is a psychedelic and agonist at the serotonin 2A receptor (5-HT2AR) that has shown positive therapeutic effects for brain disorders such as depression. To elucidate the brain effects of psilocybin, we directly compared the acute effects of 5-HT2AR agonist (psilocybin) and antagonist (ketanserin) on cerebral blood flow (CBF) using pseudo-continuous...

Consistent evidence that brain serotonin 2A receptor binding is positively associated with personality-based risk markers of depression

The British Journal of Psychiatry December 5, 2024 Emma S Høgsted, Vincent Beliveau, Brice Ozenne et al. 4 citations

Background Using [ 18 F]altanserin, a serotonin 2A receptor (5-HT 2A R) antagonist Positron Emission Tomography (PET) tracer, a positive association between cortical 5-HT 2A R binding and the inward-directed facets of neuroticism has been demonstrated in healthy individuals. Psilocybin, a 5-HT 2A R agonist, shows promise for the treatment of depression, reducing neuroticism and mood symptoms...

Amygdala response to emotional faces following acute administration of psilocybin in healthy individuals

Neuroscience Applied December 30, 2023 Sophia Armand, Kristian Larsen, Martin K Madsen et al. 7 citations

The serotonergic psychedelic psilocybin acutely induces changes in emotional states. However, it remains unresolved whether psilocybin acutely modulates amygdala reactivity to emotions, a brain region critically involved in emotion processing. Using functional magnetic resonance imaging (fMRI), we examined in 26 healthy individuals whether amygdala responses to angry, fearful and neutral faces...

Psilocybin-induced changes in brain network integrity and segregation correlate with plasma psilocin level and psychedelic experience.

European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology September 1, 2021 Martin K Madsen, Dea S Stenbæk, Albin Arvidsson et al. 132 citations

The emerging novel therapeutic psilocybin produces psychedelic effects via engagement of cerebral serotonergic targets by psilocin (active metabolite). The serotonin 2A receptor critically mediates these effects by altering distributed neural processes that manifest as increased entropy, reduced functional connectivity (FC) within discrete brain networks (i.e., reduced integrity) and increased...