Psychiatry Research Neuroimaging
November 1, 2001
Dietrich Lehmann, P.L Faber, Peter Achermann et al.
212 citations
EEG recordings from an advanced meditator showed that different meditation states—visualization, verbalization, and dissolution of self—activate distinct brain regions. Gamma-band (35–44 Hz) activity patterns differed significantly across four meditations. Visualization engaged the right posterior brain, verbalization the left central area, and self-dissolution involved right fronto-temporal regions. These findings align with known functional neuroanatomy and are discussed in relation to self-representation, reality testing, depersonalization disorders, and brain lesions.
Neurosci Biobehav Rev
February 22, 2022
Idil Sezer, Diego A. Pizzagalli, Matthew D. Sacchet
206 citations
This review synthesizes evidence on the relationship between resting-state fMRI functional connectivity and mindfulness in both clinical and non-clinical populations. The authors find that mindfulness practice is associated with altered functional connectivity in brain networks involved in attention, self-referential processing, and emotion regulation. These changes may underlie the psychological benefits of mindfulness, but the review notes that the current evidence is mixed and limited by heterogeneous methodologies and small sample sizes.
The Journal of pharmacology and experimental therapeutics
May 1, 2025
Amaya R Jenkins, Daniela B Radl, Thomas J Kornecook et al.
8 citations
Ketamine produces short-lived increases in reward responsiveness in rats under nonstressful conditions, but under ongoing chronic stress it rescues blunted reward responsiveness for nearly one week. These findings highlight the role of environmental context in ketamine's effects on reward processing and suggest its antianhedonic action may contribute to its antidepressant efficacy.
Biological Psychiatry Global Open Science
May 1, 2026
Mario Bogdanov, Jason N Scott, Shiba M Esfand et al.
1 citation
A single low dose of ketamine improves the ability to learn from rewards in both people with treatment-resistant depression and stressed rats, using nearly identical tasks. Twenty-four hours after receiving ketamine, individuals with treatment-resistant depression and chronically stressed rats showed a stronger tendency to choose the more frequently rewarded option, matching the performance of healthy controls. This effect was most pronounced in people with more severe anhedonia at the start. Ketamine did not affect general task accuracy, indicating it selectively boosts reward learning rather than overall performance. These findings point to a shared behavioral mechanism by which ketamine alleviates anhedonia, with potential implications for treating anhedonia in depression and related conditions.
medRxiv Preprint Server
June 2, 2025
Mario Bogdanov, Jason N Scott, Shiba M Esfand et al.
1 citation
preprint
A single, subanesthetic dose of ketamine improved reward responsiveness in both humans with treatment-resistant depression and chronically-stressed rats, measured using functionally identical tasks. The finding suggests that ketamine's rapid antidepressant effects may involve enhancing reward processing, a core feature of anhedonia. The work provides translational evidence linking preclinical and clinical observations, though the mechanisms remain unclear.
Neuropsychopharmacology
July 10, 2026
Christopher W. Thomas, Kayleigh S. Lamalfa, Tobias P. Whelan et al.
Psilocybin and ketamine acutely increased reward responsiveness in rats, and the effect persisted 24 hours after dosing. The increase from psilocybin, but not ketamine, was blocked by a 5-HT2A receptor antagonist. Other psychedelics, DMT and DOI, also acutely increased reward responsiveness but the effect did not last 24 hours. The non-psychedelic 5-HT2A agonist lisuride and the SSRI fluoxetine had no positive effects. These results suggest psychedelics can produce acute and enduring increases in reward responsiveness, partly through the 5-HT2A receptor, though the time course varies and clinical implications require further validation.
Translational Psychiatry
March 6, 2026
Ty Lees, Jason N Scott, Brian W. Boyle et al.
A single low dose of ketamine (0.5 mg/kg) reduced depressive, anhedonic, and ruminative symptoms 24 hours later in 24 people with treatment-resistant depression. The symptom improvement was not linked to changes in brain connectivity but was associated with connectivity patterns present before the infusion. After ketamine, participants showed broad increases in resting-state functional connectivity within and between the default mode and frontoparietal networks, as measured by EEG. The authors suggest these connectivity increases may reflect ketamine's synaptogenic effects, which can be short-lived. The study included 34 healthy controls who did not receive ketamine.