Knocking at the Doors of Perception: Relating LSD Effects on Low-Frequency Fluctuations and Regional Homogeneity to Receptor Densities in fMRIf

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Paolo La-Torraca-Vittori - , University of Pavia (Author)
  • Livio Tarchi - , University of Florence (Author)
  • Elisa Arrigo - , University of Pavia (Author)
  • Stefano Lanterna - , University of Pavia (Author)
  • Eleonora Tosi - , University of Trento (Author)
  • Arne Doose - , Division of Psychological and Social Medicine and Developmental Neurosciences (Author)
  • Fulvia Palesi - , University of Pavia (Author)
  • Doris Pischedda - , University of Pavia (Author)
  • Valdo Ricca - , University of Florence (Author)
  • Paolo Fusar-Poli - , University of Pavia, King's College London (KCL), South London and Maudsley NHS Foundation Trust, Ludwig Maximilian University of Munich (Author)
  • Stefano Damiani - , University of Pavia (Author)

Abstract

Despite a renewed scientific interest in lysergic acid diethylamide (LSD), its local neural effects remain underexplored. This functional magnetic resonance imaging (fMRI) study explored and compared LSD-induced changes in local activity (amplitude of low-frequency fluctuations: ALFF) and local connectivity (regional homogeneity: ReHo), assessing their relationship to regional receptor density. Imaging data of 15 healthy adults from an open dataset were analyzed. For each participant, two pairs of resting-state runs were available (rest1 and rest2), one performed under placebo and one following the intravenous administration of 75-μg LSD. Voxel-wise paired t-tests compared ALFF and ReHo in the LSD versus placebo conditions. Rest1*rest2 test–retest reliability and ALFF*ReHo cross-modal associations were assessed with conjunction maps and vertex-wise correlations. Finally, neurochemical enrichment analyses related LSD-induced ALFF and ReHo changes to cortical density maps of LSD-related neurotransmitter receptors and transporters. Both ALFF and ReHo decreased in somatosensory/visual cortices under LSD compared to placebo. Specific decreases were observed for ALFF in associative regions belonging to the default mode and frontoparietal networks, and for ReHo in subcortical regions (cluster-based corrected p < 0.05). Test–retest reliability was high for ALFF (rho = 0.80, p = 0.001) and moderate for ReHo (rho = 0.46, p = 0.001). ALFF*ReHo LSD-induced changes were moderately associated (rest1: rho = 0.36, p = 0.001; rest2: rho = 0.56, p = 0.001). Neurochemical enrichment analysis showed that LSD-induced ALFF/ReHo alterations were reliably and negatively correlated with the density of D2 and 5-HT1A receptors (FDR-corrected p < 0.05). These preliminary findings suggest that LSD may engage complex and dynamic neurochemical processes beyond its known 5-HT2A receptor target, warranting further investigation.

Details

Original languageEnglish
Article numbere70338
JournalEuropean journal of neuroscience
Volume62
Issue number10
Publication statusPublished - Nov 2025
Peer-reviewedYes

External IDs

PubMed 41305961
ORCID /0000-0002-5026-1239/work/202354001

Keywords

ASJC Scopus subject areas

Keywords

  • ALFF, consciousness, lysergic acid diethylamide, neuroimaging, psychedelics, ReHo