Biology subjects

Ramaekers, J.

Publications and source records attributed to Ramaekers, J..

6 recordsLinked to original sources

bioRxiv2026

Tuning in together: LSD enhances inter-brain synchrony and felt connectedness in romantic couples

Social connection is fundamental to human wellbeing. Serotonergic psychedelics such as lysergic acid diethylamide (LSD) acutely heighten subjective connectedness, yet their effects on real-time social connection remain poorly understood. Using EEG hyperscanning in a randomized, double-blind, placebo-controlled crossover study, we recorded neural activity simultaneously from both members of healthy romantic couples (N=25) who received LSD (50 g) or placebo together, across resting and interactive states. LSD increased subjective connectedness, including feelings of love, closeness, trust, and being "in sync," while reducing loneliness, compared to placebo. This affiliative shift dissociated from the drugs pharmacokinetic time-course, remaining elevated as subjective intensity and plasma concentration declined. In parallel, LSD increased inter-brain synchrony during shared rest, carried specifically by theta-band amplitude-envelope coupling. Importantly, this effect survived two complementary controls. First, it exceeded coupling between unrelated individuals and second the effects depended on contemporaneous neural alignment rather than shared drug-induced dynamics. Exploratory analyses showed that romantic partners with greater resting synchrony reported greater feelings of connectedness. These findings provide the first evidence that a psychedelic enhances brain-to-brain coupling between people, linking a pharmacologically induced state of felt connection to a measurable signature shared across interacting brains.

neuroscience↗

bioRxiv2026

Temporal effects of a single oral dose of psilocybin on plasma circulating miRNAs in healthy young adults.

BackgroundPsilocybin, a classic psychedelic, produces acute alterations in brain function, and has shown sustained therapeutic effects in psychiatric disorders. However, most studies focus on acute brain imaging readouts (e.g., fMRI) and rarely assess longer-term molecular changes. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression, are enriched in the brain, and can be released into blood, potentially indexing brain-relevant molecular processes. We hypothesised that a single psilocybin dose would show acute changes in miRNAs with predicted relevance to neuroplasticity related signalling and immune/inflammatory regulation in healthy adults. MethodsIn a randomised, double-blind, placebo-controlled study (N=62; 31 psilocybin, 31 placebo), volunteers received psilocybin (0.17 mg/kg) or placebo. Blood was collected at baseline, 360 minutes, and 7 days after dosing. Plasma miRNAs were quantified by small RNA sequencing. Elastic net regression was used for feature selection, followed by differential expression analysis and validation with linear mixed models. Pathway enrichment used Reactome and Gene Ontology. ResultsTwo circulating miRNAs (let-7g-5p and miR-150-5p) met criteria for differentially expressed at 360 minutes following psilocybin administration, with no significant differences detected at 7 days or in the placebo condition under the statistical thresholds used. Over representation analysis suggested enrichment of molecular processes involved in neuroplasticity (e.g., TrkA, MAPK), inflammation (e.g., IL-6, TGF-{beta}), and transcriptional regulation (e.g., RNA polymerase II, SMAD2/3/4). ConclusionsA single oral dose of psilocybin was associated with transient alterations in circulating miRNA expression, consistent with an acute shift in circulating gene-regulatory miRNA signals, without sustained miRNA changes at 7 days. These findings provide initial evidence that circulating miRNA changes after psilocybin may reflect acute molecular process responses and support further investigation of circulating miRNAs as potential biomarkers of psychedelic-induced molecular responses.

neuroscience↗

bioRxiv2026

Circulating MicroRNAs and Their Associations with Neurotrophic, Inflammatory and Glutamate Markers in Healthy Volunteers

Psilocybin acutely alters neurotrophic, neurochemical, and immune markers, but the relationships between these responses and circulating microRNAs (miRNAs), i.e. non-coding RNAs that regulate post-transcriptional gene expression, remain unclear. In a randomized, double-blind, placebo-controlled study of 62 healthy adults who received psilocybin (0.17 mg/kg) or placebo, we previously demonstrated that let-7g-5p and miR-150-5p were transiently differentially expressed 360 minutes after psilocybin administration. Here, we examined whether changes in these miRNAs were associated with concurrent neurotrophic, inflammatory, pharmacokinetic, and glutamatergic measures. Expression changes from baseline to 360 min and 7 days were analysed using linear regression against changes in BDNF, TNF-, IL-6, C-reactive protein, cortisol, medial prefrontal cortex glutamate/total creatine, and psilocin concentrations. Psilocybin increased let-7g-5p and decreased miR-150-5p expression. Changes in let-7g-5p were positively associated with psilocin concentrations, suggesting sensitivity to inter-individual pharmacokinetic variability, whereas miR-150-5p showed no concentration-dependent association. In both groups, miRNA changes were negatively related to baseline expression: lower baseline let-7g-5p predicted larger increases, whereas higher baseline miR-150-5p predicted larger decreases. BDNF changes were associated with both miRNAs under placebo but not psilocybin, consistent with reduced between-subject variability and a flattened BDNF-miRNA relationship following treatment. Medial prefrontal glutamate was negatively associated with miR-150-5p change under psilocybin. No associations were found with immune biomarkers. Together, these findings support the predicted involvement of let-7g-5p and miR-150-5p in neuroplasticity and their potential as accessible blood-based biomarkers of individual neurobiological responsiveness to psilocybin and other psychedelics.

neuroscience↗

bioRxiv2025

Unmixing the Psychedelic Connectome: Brain Network Traits of Psilocybin

Psilocybin induces profound alterations in consciousness, yet prevailing neural models often describe a monolithic change in brain connectivity that may not fully capture the multifaceted nature of the psychedelic state. To test the hypothesis of a composite neural state, this study applied a robust, data-driven framework, Connectome Independent Component Analysis (connICA) with multi-level resampling, to resting-state fMRI data from healthy volunteers. The analysis decomposed connectomes into statistically independent functional connectivity traits ("FC-Traits"), revealing a primary trait whose expression was significantly modulated by plasma psilocin concentration, providing a whole-cortical signature of the drugs physiological action. Crucially, a second, distinct trait was also isolated, which independently associated with impaired performance on a visual divergent thinking task. These findings demonstrate that the acute psilocybin state is a composite of co-occurring neural processes. This validates the application of a decompositional connectomic framework to move beyond global descriptions and successfully disentangle the specific neural patterns underlying distinct pharmacological and cognitive correlates.

neuroscience↗

bioRxiv2023

The unique neural signature of your trip: Functional connectome fingerprints of subjective psilocybin experience

The emerging neuroscientific frontier of brain fingerprinting has recently established that human functional connectomes (FCs) exhibit fingerprint-like idiosyncratic features, which map onto heterogeneously distributed behavioural traits. Here, we harness brain-fingerprinting tools to extract FC features that predict subjective drug experience induced by the psychedelic psilocybin. Specifically, in neuroimaging data of healthy volunteers under the acute influence of psilocybin or a placebo, we show that, post psilocybin administration, FCs become more idiosyncratic due to greater inter-subject dissimilarity. Moreover, whereas in placebo subjects idiosyncratic features are primarily found in the frontoparietal network, in psilocybin subjects they concentrate in the default-mode network (DMN). Crucially, isolating the latter revealed an FC pattern that predicts subjective psilocybin experience and is characterised by reduced within-DMN and DMN-limbic connectivity, as well as increased connectivity between the DMN and attentional systems. Overall, these results contribute to bridging the gap between psilocybin-mediated effects on brain and behaviour, while demonstrating the value of a brain-fingerprinting approach to pharmacological neuroimaging. Author summaryThe trending field of brain fingerprinting focuses on characterising fingerprint-like idiosyncratic features of human functional connectomes (FCs), which have been shown to predict heterogeneously distributed behavioural traits. Here, we apply brain-fingerprinting methods to fMRI data from subjects who were administered the psychedelic psilocybin or a placebo. We find that, compared to the placebo condition, subjects under acute psilocybin effects exhibited more idiosyncratic FCs, with idiosyncratic features being largely concentrated in the default-mode network (DMN). Furthermore, we isolated an idiosyncratic FC pattern that predicted reports of subjective psilocybin experiences. This pattern was characterised by altered DMN connectivity, specifically by reduced within-DMN and DMN-limbic connectivity, and increased connectivity between the DMN and attentional systems. This work paves the way for exciting new research harnessing pharmacological brain fingerprinting.

neuroscience↗

bioRxiv2021

Spatial patterns in functional brain connectomes reflect acute and chronic cannabis use.

Resting state fMRI has been employed to identify alterations in functional connectivity within or between brain regions following acute and chronic exposure to {Delta}9-tetrahydrocannabinol (THC), the psychoactive component in cannabis. Most studies focused a priori on a limited number of local brain areas or circuits, without considering the impact of cannabis on wholebrain network organization. The present study attempted to identify changes in the wholebrain human functional connectome as assessed with ultra-high field (7T) resting state scans of occasional (N=12) and chronic cannabis users (N=14) during placebo and following vaporization of cannabis. Two distinct data-driven methodologies, i.e. network-based statistics (NBS) and connICA, were used to identify changes in functional connectomes associated with acute cannabis intoxication and chronic cannabis use. Both methodologies revealed a broad state of hyperconnectivity within the entire range of major brain networks in chronic cannabis users compared to occasional cannabis users, which might be reflective of an adaptive network reorganization following prolonged cannabis exposure. The connICA methodology also extracted a distinct spatial connectivity pattern of hypoconnectivity involving the dorsal attention, limbic, subcortical and cerebellum networks and of hyperconnectivity between the default mode and ventral attention network, that was associated with the feeling of subjective high during THC intoxication across both user groups. Whole-brain network approaches identified spatial patterns in functional brain connectomes that distinguished acute from chronic cannabis use, and offer an important utility for probing the interplay between short and long-term alterations in functional brain dynamics when progressing from occasional to chronic use of cannabis.

neuroscience↗