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Grega Repovš

University of Ljubljana

5 papers in the library · 628 citations · publishing 2018-2025

Papers

Changes in global and thalamic brain connectivity in LSD-induced altered states of consciousness are attributable to the 5-HT2A receptor

eLife October 25, 2018 Katrin H. Preller, Joshua B. Burt, Jie Lisa Ji et al. 416 citations

Lysergic acid diethylamide (LSD) reduces associative brain connectivity while increasing sensory-somatomotor and thalamic connectivity. These neural effects, along with the subjective experience, are fully blocked by ketanserin, a selective 5-HT2A receptor antagonist. The spatial pattern of LSD's effects across the brain matches the distribution of 5-HT2A receptor gene expression in humans. These results strongly implicate the 5-HT2A receptor in LSD's neuropharmacology, informing the neurobiology of psychedelics and guiding development of psychedelic-based therapeutics.

Psilocybin Induces Time-Dependent Changes in Global Functional Connectivity

Biological Psychiatry January 13, 2020 Katrin H. Preller, Patricia Duerler, Joshua B. Burt et al. 199 citations

Psilocybin reduces connectivity in associative brain regions while increasing connectivity in sensory regions, a pattern that emerges over time from administration to peak effects. Baseline connectivity predicts the extent of these changes. The shifts correlate with spatial gene expression patterns of the serotonin 2A and 1A receptors, pinpointing their critical role in the psychedelic state. These findings suggest that sensory integration and associative disintegration may underlie the psychedelic experience, and baseline connectivity could serve as a predictive marker for personalized psychedelic treatment.

What is it like to do a visuo-spatial working memory task: A qualitative phenomenological study of the visual span task.

Consciousness and cognition February 1, 2024 Aleš Oblak, Oskar Dragan, Anka Slana Ozimič et al. 8 citations

Working memory is usually measured with psychological tasks that focus on the reliability of outcomes rather than how participants experience the tasks. This study replicated protocols for investigating the lived experience of working memory using a visual span task. Eighteen healthy participants aged 21 to 35 provided subjective reports. Working memory was phenomenologically characterized at three time scales: background feelings, strategies, and tactics. At the level of tactics, transmodality—the transformation of one modality of lived experience into another—was identified as the central dynamic during task performance.

Ketamine induces multiple individually distinct whole-brain functional connectivity signatures

bioRxiv Preprint Server November 1, 2022 Flora Moujaes, Jie Lisa Ji, Masih Rahmati et al. 4 citations preprint

Ketamine is a promising therapy for treatment-resistant depression, but why some people respond better than others remains unclear. The molecular mechanisms of ketamine are not yet connected to its effects on brain activity and behavior.

Ketamine Alters Tuning of Neural and Behavioral Spatial Working Memory Precision

bioRxiv Preprint Server February 10, 2025 Masih Rahmati, Flora Moujaes, Nina Purg Suljič et al. 1 citation preprint

Working memory deficits in disorders like schizophrenia may stem from disrupted brain cell tuning. Using fMRI, researchers found that ketamine, which blocks NMDA receptors, broadens neural spatial tuning in healthy people, reducing the precision of brain responses across visual, parietal, and frontal areas and worsening spatial working memory accuracy. These tuning changes were more consistent across individuals and brain regions than overall activation changes and correlated with memory performance. The results link NMDA receptor disruption to altered brain circuit dynamics and memory impairment, offering a target for developing treatments.