Progress in Neuro-Psychopharmacology and Biological Psychiatry

BackgroundSchizophrenia (SCZ) is a severe neurodevelopmental disorder with numerous genetic risk loci. However, little is known about the molecular alterations that occur during brain development in SCZ, particularly regarding the role of microRNA (miRNA) mediated regulatory mechanisms. This gap in knowledge is largely due to the limited availability of developing human brain tissue. Patient-derived brain organoids offer a promising alternative model. Here we use 3D dorsal forebrain organoids (DFOs) to investigate miRNA dysregulation in SCZ. MethodsDFOs were generated from human induced pluripotent stem cells (hiPSCs) derived from six SCZ patients and five matched controls and cultured for 120 days. Multi-omics analyses, immunohistochemistry, and in situ hybridization were employed to characterize molecular and spatial features. ResultsDFOs recapitulated key molecular hallmarks of human cortical development. Nineteen miRNAs were differentially expressed in SCZ: nine associated with neural progenitor proliferation were downregulated and ten linked to neuronal differentiation and synaptic maturation were upregulated, reflecting a compressed developmental timeline. Among 77 dysregulated mRNAs, 55 were predicted miRNA targets. SCZ DFOs exhibited significant upregulation of GABAergic pathway genes accompanied by altered expression of their regulatory miRNAs, indicating premature GABAergic lineage specification. The disrupted miRNA-mRNA network converged on glutamatergic and dopaminergic development, synaptic organization, and extracellular matrix remodeling. ConclusionDysregulated miRNAs in SCZ DFOs disrupt neuronal differentiation, excitatory-inhibitory balance, and early circuit formation, implicating miRNA-mediated post-transcriptional regulation as a key mechanism linking molecular alterations to cellular and network-level deficits in SCZ.

Social behavior is a fundamental phenotype across vertebrates. Zebrafish (Danio rerio) have emerged as a valuable translational model for investigating the neurobiological mechanisms underlying sociability, particularly due to their robust shoaling behavior and experimental tractability. However, the literature presents issues of reproducibility and inconsistent findings regarding the modulation of social preference and shoal cohesion in adult zebrafish. We conducted a systematic review and meta-analysis to synthesize studies evaluating the effects of pharmacological interventions that modulate the central nervous system and stress-related interventions on social behavior in adult zebrafish and, when available, anxiety-like behavior. The literature search was performed in three databases (Embase, PubMed, and Web of Science), followed by a two-step screening process based on inclusion/exclusion criteria. The included studies underwent extraction of qualitative and quantitative data, as well as risk of bias assessment. Interventions from the included studies (n = 108) were categorized according to their nature, mechanism of action, and/or therapeutic purpose, resulting in seven, four, and five meta-analyses for social preference, shoal cohesion, and anxiety-related tests, respectively. Ethanol, NMDA antagonists, pro-dopaminergic agents, and stress-related interventions decreased social preference, while stress-related interventions increased shoal cohesion. The fact that stress produced opposite effects suggests that these paradigms measure distinct sociability constructs, or perhaps are differentially modulated by confounding factors, like anxiety for example. The studies presented high heterogeneity, with prediction intervals compatible with effects in both directions, as well as methodological limitations and deficiencies in data reporting, as evidenced by the risk of bias assessment. These findings emphasize the need for well-designed new studies to validate the findings and expand the evidence on interventions that currently lack sufficient studies for quantitative synthesis.

Background: Obsessive-compulsive disorder (OCD) is characterized by disturbing thoughts (obsessions) that initiate anxiety-reducing thoughts or behaviors (compulsions). For patients with treatment-resistant OCD (tr-OCD), neuromodulation techniques, like capsulotomy (a lesion in the anterior limb of the internal capsule) and deep brain stimulation (DBS), have emerged as interventions that likely regulate connectivity between the prefrontal cortex (PFC) and subcortical targets. Three patients (Cap-DBS1-3) underwent a failed capsulotomy followed by successful DBS. Here, we aimed to understand the brain connections disrupted by failed capsulotomy vs modulated by successful DBS. Methods: We used diffusion-weighted magnetic resonance imaging (dMRI) tractography in a control cohort with tr-OCD (n=12) and in two of the Cap-DBS patients themselves to determine connectivity profiles of the capsulotomy, volume of tissue activated (VTA), and potentially necessary tracts (VTA minus capsulotomy tracts). We used whole-brain, PFC-focused, and subcortically-focused tractography algorithms to fully explore the space of possible connections. Results: Capsulotomy regions-of-interest (ROIs) connected with a variety of PFC and subcortical regions. VTA ROIs and potentially necessary tracts had limited and inconsistent PFC connectivity but substantial subcortical connectivity. While correlated to the average OCD connectome (r = 0.214, 95% CI [0.177, 0.251]; r = 0.756, 95% CI [0.739, 0.772]), the Cap-DBS connectomes had many edges that were stronger (z-score > 3). Conclusions: The connectivity profile of potentially necessary tracts for successful DBS treatment after failed capsulotomy revealed a surprising proportion of subcortical regions and inconsistent PFC involvement, highlighting an often-ignored set of connections that may be critical to effective DBS.

Background and Objectives In ADHD, a heterogeneous neurodevelopmental condition, behavioral and motor manifestations may reflect multiple inefficient or perturbed inhibitory systems. To evaluate Transcranial Magnetic Stimulation (TMS) evoked cortical silent period (CSP) duration, an indicator of GABA(B) receptor-mediated inhibition in motor cortex, as a potential biomarker of Attention-Deficit/Hyperactivity Disorder (ADHD) in children. Method We retrospectively analyzed TMS data, obtained using both round and figure-of-8 coils, from three cross-sectional studies conducted in 8- to 12-year-old children with ADHD (n=79; 10.7 +/- 1.5 years old) and age-and-sex-matched typically developing controls (n=96; 10.5 +/- 1.4 years old). Results Median CSP was 32% shorter in ADHD (p=0.02). Regression analysis demonstrated a relationship between shorter CSP and both lower active motor thresholds (p < 0.0001) and more severe hyperactivity symptom rating (p = 0.026). Test-retest CSP measures in 83 children showed moderate reliability (intraclass correlation 0.77 [ADHD], 0.75 [controls]). Conclusion TMS-evoked CSP may be a useful biomarker in future investigations of ADHD subtypes, domains of impaired function, or treatment outcomes.

Stressors are commonly used in rats to induce models of anxiety or depression. The effectiveness of these stressors is often evaluated using specific behavioural tests. In a previous meta-analysis of chronic variable stress (CVS) procedures, we predicted that longer and more intensive stress procedures would result in larger effect sizes in behavioural tests. However, we found that the duration or intensity of CVS procedures did not correlate strongly with the magnitude of the effect sizes reported in behaviouraltests. In that study, we were concerned that the large and unexplained diversity in CVS procedure design, both in terms of duration and the types of stressors used, made it challenging to detect the factors that were influencing effect size. In an effort to address this, we explore here the use of a much simpler stress procedure - chronic restraint stress (CRS) - to study the relationship between the duration of CRS procedures and the effect sizes obtained in subsequent behavioural tests. We searched PubMed for articles using CRS procedures with rats, systematically documented the total duration of restraint, and carried out a meta-analysis of the effect sizes obtained in four behavioural tests: the forced swim test (FST), the sucrose preference test (SPT), the elevated plus maze (EPM) and the open field test (OFT). We found that chronic restraint stress increased immobility in the FST, decreased sucrose preference in the SPT, decreased time spent in the open arms of the EPM but had no effect on time spent in the centre of the OFT. However, the effect sizes in all behavioural tests, except the SPT, were not moderated by the duration of the CRS procedure, indicating that longer CRS procedures are associated with larger effect sizes in the SPT but not in the FST or EPM.

Psychiatric disorders, such as attention-deficit/hyperactivity disorder, autism spectrum disorder, and schizophrenia, are clinically heterogeneous and lack objective biomarkers for reliable diagnosis. Although blood transcriptomic data have been proposed as a potential source of diagnostic information, their generalizability across independent cohorts remains unclear. This study aimed to assess whether biologically informed measures of dynamic instability enhance the reproducibility and generalizability of psychiatric classifications based on peripheral blood data by integrating publicly available blood transcriptomic datasets from multiple cohorts and evaluating classification performance using individual-level cross-validation and study-level holdout validation. To investigate the underlying biological structure, we applied a dynamic systems framework, including pseudotime-based vector field inference and attractor analysis. Additionally, we introduced temporal entropy as a measure of dynamic instability in the inferred transcriptomic trajectories. High classification performance was observed in individual-level cross-validation (area under the receiver operating characteristic [AUROC] > 0.8 across several comparisons); however, performance decreased substantially in study-level validation (AUROC {approx} 0.5-0.7), indicating limited generalizability. Attractor analysis revealed that transcriptomic states formed continuous and overlapping structures rather than distinct diagnostic clusters. Stratification based on temporal entropy identified a subset of individuals with unstable transcriptomic dynamics, and excluding these individuals improved the classification performance across most diagnostic pairs (AUROC > 0.7). These findings suggest that transcriptomic variability and dynamic instability contribute to the limited reproducibility of psychiatric classifications. Incorporating temporal entropy as a measure of system-level instability may enhance the robustness and interpretability of biomarker-based models and provide a new perspective on psychiatric disorders as dynamic systems.

Schizophrenia is a serious mental disorder that changes the way people think, perceive, and manage daily life. Getting the diagnosis right is critical for proper treatment, but in practice it is often difficult. Current evaluations depend mostly on a clinicians judgment, and the overlap of symptoms with bipolar disorder or major depression makes the task even harder. EEG offers a safe and noninvasive way to study brain activity, yet no single EEG feature has been reliable enough to stand on its own. This makes it important to look at integrative approaches that bring together different aspects of brain dynamics. In this study, we analyzed EEG features to distinguish patients with schizophrenia from healthy controls. Spectral power was measured across {delta}, {theta}, , {beta}, and {gamma} bands. Temporal irregularity was quantified with Multiscale Permutation Entropy (MPE), which to our knowledge represents the first application of MPE to EEG in schizophrenia. Functional connectivity was estimated with the weighted Phase Lag Index in {theta}, , and {beta} bands, followed by extraction of graph measures including global efficiency, clustering coefficient, characteristic path length, and mean strength. These features were used to train Random Forest, Multi-Layer Perceptron, and Support Vector Machine classifiers. Among the models, Random Forest achieved the most reliable performance, reaching 99.7% accuracy under stratified 5-fold validation and 99.6% under leave-one-subject-out validation. Feature analysis showed that connectivity in {theta} and bands contributed most strongly to classification. Topographic maps of {theta}, , and {beta} activity also revealed regional group differences. Overall, the results suggest that combining spectral, entropy, and connectivity measures offers a promising framework for EEG-based detection of schizophrenia. Nevertheless, these findings are preliminary given the limited sample size (N=28), and replication in larger and more diverse cohorts is required before clinical translation.

Perceptual learning is a temporally dynamic process involving the acquisition and integration of sensory information necessary for adaptive decision making. Resolving the neural basis of perceptual learning could uncover new therapeutic targets for schizophrenia and other neurodevelopmental disorders that implicate impaired perceptual acuity. In the present study, we developed a novel touchscreen task which utilizes orientation discrimination to assess visual perceptual learning (VPL) in male and female rats. Based on previous evidence we hypothesised that VPL would depend on inhibitory neurotransmission mediated by {gamma}-amino butyric acid (GABA). Segregating subjects based on poor learning (lower tertile) and good learning (upper tertile) revealed dose-dependent improvements in VPL in poor learners following the administration of a GABA-B agonist (R-baclofen) and an 5 subunit specific GABA-A (GABRA5) positive allosteric modulator (alogabat) administered early in learning. Poor VPL performance was associated with a significant reduction in GABRA5 expression in dorsal regions of the prefrontal cortex (PFC), most notably the prelimbic cortex. Reduced GABRA5 expression in this region was co-localized to somatostatin- and parvalbumin-expressing interneurons. These findings indicate that inter-individual variation in the expression of GABRA5 in selective PFC populations of inhibitory interneurons may determine the speed and acuity of VPL. Based on these findings, interventions that restore GABRA5 signalling in the PFC may hold therapeutic relevance for neuropsychiatric disorders involving deficits in perceptual learning.

Alcohol use disorder (AUD) is a significant public health concern. In Canada, about 18% of individuals aged 15 or older will meet the clinical criteria for AUD at some point in their lives (CAMH, 2023). Treatment options for AUD are limited, and the high relapse rates highlight the urgent need for innovative methods to study and address AUD. Zebrafish (Danio rerio) is an emerging model for exploring the neurobiological impacts of alcohol. Previous studies have demonstrated that zebrafish respond to the rewarding effects of alcohol, but most research methods rely on passive administration, such as immersion, which does not reflect the typical routes of alcohol intake in humans. We previously showed that zebrafish can learn to self-administer drugs of abuse in small groups and conditioned animals are displaying key features of substance abuse disorders. However, group-based conditioning limits our understanding of individual drug preference and intake profile. In this study, we improved upon our previous design by establishing an individual self-administration protocol to measure voluntary alcohol intake and model alcohol use disorder. In this novel assay, individual adult fish learn to discriminate between two zones to self-administer a 5% ethanol solution. Moreover, animals conditioned in this assay can perform progressive ratio and display signs of withdrawal upon cessation of ethanol intake. These results suggest zebrafish can develop ethanol abuse-like behaviour, providing a powerful platform to study genetic predisposition and screen for therapeutic compounds.

ObjectiveTobacco use is a leading cause of mortality in schizophrenia, but treatments are partially effective. Default mode network (DMN) pathology is linked to tobacco use in schizophrenia, and transcranial magnetic stimulation (TMS) applied to the DMN affects craving in schizophrenia. To advance TMS therapeutics for tobacco use in schizophrenia, we used TMS experiments to 1) determine optimal stimulation parameters then 2) compare our optimal parameters against a well-established, effective TMS intervention for craving. MethodsIn Protocol Optimization TMS, nicotine-using individuals with schizophrenia (n=10) received single sessions of DMN-targeted TMS with pre/post neuroimaging and craving assessment. Neuroimaging analysis revealed bilateral parietal DMN connectivity was associated with craving change. In Comparative Effectiveness TMS (n=62), nicotine-using individuals with schizophrenia and non-psychosis controls participated in a crossover study comparing DMN-targeted and left dorsolateral prefrontal cortex (DLFPC)-targeted TMS with pre/post neuroimaging and craving assessment. Mixed effects models were used to determine effects of target, group, and relationship between craving change and connectivity change. ResultsIn Protocol Optimization TMS, increased craving was associated with increased bilateral parietal DMN connectivity (mean pFDR<0.012, r=0.60). In Comparative Effectiveness TMS, both interventions reduced craving (DLPFC: p=0.0015; DMN: p=0.0054) and bilateral parietal DMN connectivity (DLPFC: p=0.024; DMN: p=0.022). There was an interaction of bilateral parietal DMN connectivity change, group, and age (p=0.001) where connectivity change was associated with craving change in older individuals with schizophrenia (p=0.041) but not other groups. ConclusionsBilateral parietal DMN connectivity is a novel mechanism underlying craving in schizophrenia that can be engaged for therapeutic benefit.

Acute COVID-19 outcomes are exacerbated by substance use, however, the impact of substance use on Long-COVID is unknown. Here, we investigated the impact of chronic cocaine administration on spike-induced Long-COVID-like outcomes in the rat. Rats received intermittent chronic cocaine administration and a single intravenous injection of the SARS-CoV-2 spike protein. Two months following spike administration, Long-COVID-like outcomes were assessed. Exposure to spike protein in the presence of cocaine produced a persistent reduction in weight gain as compared with controls or spike protein alone. Further, cocaine-treated rats exposed to spike had lower withdrawal thresholds compared to control animals as well as their own baseline, suggesting increased pain sensitivity. Spike and/or cocaine increased the ratio of interleukin-6 (IL-6) to interleukin-10 (IL-10) levels in the hippocampus, indicating a shift towards a proinflammatory state. Paw withdrawal thresholds were positively correlated with IL-10 levels in the hippocampus and prefrontal cortex. Regarding olfaction, rats exposed to spike spent less time sniffing an odor attractant. Cocaine produced an anxiolytic-like phenotype during the elevated plus maze test. Further analysis of behaviors on the maze revealed that the latency to enter the open arms was shorter in rats exposed to spike or cocaine, suggesting a possible impulsive-like phenotype in these animals. These findings demonstrate the negative impact of cocaine on Long-COVID-like outcomes suggesting a need for increased clinical observations of people with co-occurring Long-COVID and cocaine use disorder. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=59 SRC="FIGDIR/small/729575v1_ufig1.gif" ALT="Figure 1"> View larger version (10K): org.highwire.dtl.DTLVardef@12fdc19org.highwire.dtl.DTLVardef@11b1b0dorg.highwire.dtl.DTLVardef@8d1e21org.highwire.dtl.DTLVardef@b53d20_HPS_FORMAT_FIGEXP M_FIG C_FIG

Post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD) are chronic psychiatric disorders that have overlapping symptomology and risk factors, including altered motivation and impulsive behavior. Inescapable exposure to a predator odor stressor (2,3,5-Trimethyl-3-Thiazoline (TMT)) produces PTSD-like symptomology in rats. Individual differences in stress-coping behaviors such as freezing and defensive digging during TMT exposure can predict long-term differences in alcohol-related behaviors and altered neurobiology. Here, we sought to evaluate the relationship between stress coping behavior during TMT exposure and different aspects of decision making. In Experiment 1, male and female rats were trained on an adjusting-amounts delay discounting task, and delay discounting curves were established before and >2 weeks after TMT exposure. In Experiment 2, female rats were trained to self-administer alcohol and sucrose in a concurrent choice procedure. Lever responses and preference for alcohol over sucrose were evaluated before and >2 weeks after TMT exposure, and then motivation for competing reinforcers was evaluated using progressive ratios. Active coping (digging) during TMT exposure was correlated with increased post-TMT impulsive choice (Experiment 1), reduced sucrose lever responses both before and after TMT exposure (Experiment 2), and reduced sucrose lever breakpoint (Experiment 2). Additionally, TMT-exposed rats had increased motivation for both alcohol and sucrose self-administration when available concurrently (Experiment 2). Overall, these findings suggest that behavior prior to and during a stressful experience can predict susceptibility to negative effects on decision making, which may help future studies identify the neurobiology underlying risk for aberrant reward-related behaviors after a traumatic event.

The fear circuit orchestrates defensive responses to environmental threats and is essential for survival. Dysregulation of this system is thought to contribute to the pathophysiology of several psychiatric disorders. Within this fear circuit, the corticolimbic network, particularly the amygdala and the medial prefrontal cortex (mPFC), is strongly modulated by serotonin. Previous studies have shown that Htr3a knockout (Htr3a-KO) mice exhibit deficits in the extinction of cued fear memory; however, the circuit level mechanisms underlying these impairments remain unknown. Here, we investigated this question by recording local field potentials evoked by auditory conditioned stimuli (CS) in the prelimbic (PrL), infralimbic (IL), and basolateral amygdala (BLA) of head-fixed wild-type (WT) and Htr3a-KO mice prior to fear conditioning and during fear memory retrieval. Behaviorally, Htr3a-KO mice displayed a delayed attenuation of fear-induced freezing during cued fear memory retrieval, whereas WT mice showed a rapid attenuation in freezing. Electrophysiologically, Htr3a-KO mice exhibited reduced fear-evoked theta power in the PrL, IL, and BLA, along with diminished mPFC-BLA theta synchrony. Moreover, theta-phase modulation of gamma oscillations within the BLA, which has been shown to increase during fear states, was perturbed in the absence of Htr3a signaling. Together, these findings indicate that Htr3a is critical for maintaining proper oscillatory dynamics within the mPFC-BLA circuit and for supporting effective attenuation of learned fear. Highlights- Attenuation of fear responses during fear memory retrieval sessions is protracted in Htr3a knock-out mice - The fear-induced theta response in the medial prefrontal cortex and the basolateral amygdala is less powerful in the Htr3a knock-out mice than in wild-type - Htr3a knock-out mice show a deficit in fear-induced synchronization as well as in theta modulation of gamma power in the cortico-limbic network - These results suggest that malfunction of the Htr3a receptor cause alterations in fear network circuit mechanisms that might be linked to deficits in fear responses attenuation

Lack of social interaction results in various behavioral abnormalities in rodents, including increased anxiety levels, altered sociability, and impaired cognitive ability. Epigenetic factors regulate gene expression, however, how they contribute to juvenile social isolation (jSI)-induced behavioral alterations remains largely unknown. Here, we focused on the nucleus accumbens (NAc), a critical brain region of the reward system that regulates motivation-related behaviors. We first performed RNA-seq on neuronal nuclei and found alterations in genes related to neuronal function, as well as in transcriptional and epigenetic regulation. Protein-protein interaction (PPI) analysis of differentially expressed genes (DEGs) showed that top key nodes among down-regulated genes include membrane receptors (Ntrk2, Grin3a, and Grik1) and an apoptosis regulator (Bcl2). To further investigate whether jSI-induced gene expression alterations are mediated by histone modifications, we next performed CUT&Tag for four histone modifications (H3K4me1, H3K4me3, H3K27ac, and H3K27me3), and the results implied that epigenetic alterations may also play a role in neuronal function as well as transcriptional regulation. Reanalysis of previously published RNA-seq data on the manipulation of histone modification-associated factors (including Kdm6b, Brd4, and Setd1a) suggested that these enzymes were probably involved in jSI-induced gene expression alterations. Taken together, our comprehensive analysis implies the involvement of histone modification regulation in jSI-related alterations of gene expression in NAc.

BackgroundNon-suicidal self-injury (NSSI) represents a growing public health concern, particularly in adolescents. Emotion dysregulation is central to prevailing NSSI models, yet it remains unclear whether acceptance-based emotion regulation (ER) and its underlying neural processes are disrupted in naturalistic, dynamic contexts. MethodsPre-registered neuroimaging trial in recently diagnosed and treatment-naive adolescents with NSSI (n=25) and healthy controls (n=25) using an ER paradigm with dynamic video clips and concomitant functional magnetic resonance imaging. Behavioral, neural activity, and connectivity indices during emotion reactivity and acceptance-based regulation were compared between groups. ResultsAdolescents with NSSI experienced elevated negative feelings during neutral clips, reflecting heightened baseline negativity. In comparison to controls, they displayed reduced temporal and ventrolateral prefrontal engagement during emotional reactivity, but increased engagement of regions implicated in both emotion reactivity (right amygdala, insula) and ER (right dlPFC, dmPFC, vlPFC) when utilizing acceptance. Higher activation in the right dlPFC was positively associated with difficulties in accessing ER strategies in everyday life. Adolescents with NSSI showed reduced functional connectivity between the right amygdala and left dlPFC. ConclusionsAdolescents with NSSI exhibited a baseline negativity bias and altered neural engagement during both negative emotional reactivity and acceptance-based regulation, characterized by increased activation and reduced amygdala-dlPFC connectivity. These findings highlight atypical emotion processing in real-life contexts in individuals with NSSI. Targeting acceptance-based regulation and prefrontal-limbic circuitry may represent a promising intervention approach for adolescents with NSSI.

Cannabis (marijuana) is the most widely used recreational drug in the USA accounting for about 62 million users in 2024. Among cannabis users, 26% are of prime reproductive age (18-25 years). Delta-9 tetrahydrocannabinol (THC) is the principal psychoactive component of cannabis and has been detected in human seminal fluids. Although abundant evidence indicates adverse effects of THC exposure on spermatogenesis in different species, acute effects of THC on postejaculatory sperm including fertilization potential and subsequent carryover effects on embryo development are largely unknown. The present study was designed to provide missing information on structural and mechanistic effects of THC exposure to postejaculatory sperm function by evaluating sperm indices often overlooked or masked during clinical evaluation. A bovine embryo continuum model was employed to determine effects of THC on sperm structure, kinematics, bioenergetics, and binding mechanisms. Effects of THC on the sperm genomic and epigenomic landscape were determined, complemented by paternal carry over effects on embryo development as a human translational model to elucidate paternal effects on future development, and to mirror sperm exposure during transport within the female reproductive tract. Cryopreserved bovine sperm from three bulls were independently exposed to physiologically relevant concentrations of THC (0 and 32nM, n = 2 individual replicates/bull) for 24 h under non-capacitating conditions at 25{degrees}C followed by quantification of sperm kinematics at 37{degrees}C. Samples of THC-exposed sperm and vehicle-control (0.1% DMSO) were collected in replicate following immediate addition of THC (0 h) and again at 24 h. DNA damage, acrosome integrity, bioenergetics, changes to DNA methylation and embryo development were quantified. Data were analyzed by logistic regression with a generalized linear mixed effect model. Computer-assisted sperm assessment revealed a reduction in progressive motility of THC-exposed sperm after 24 h while other parameters were not affected. Acrosome integrity as determined by flowcytometric analysis with FITC-PSA was severely compromised in THC-exposed sperm (P [&le;] 0.05), despite no detectable difference in capacitation status using merocyanine staining. Similarly, DNA integrity as determined by TUNEL assay was significantly impaired after 24 h of THC exposure (P [&le;] 0.05). Mechanistic effects of THC were explored through characterization of the transmembrane G-protein coupled cannabinoid 1 receptor (CB1). CB1 is expressed in the post-acrosomal region and its abundance decreased as compared to unexposed sperm. Alterations to the methylation landscape of sperm were then determined after 24 h of THC exposure through whole-genome Enzymatic Methyl Sequencing. PCA analysis indicated that sperm from different males formed distinct clusters, implying individual differences among bulls, while the effects of THC exposure produced tighter clusters. Paternal carryover effects on embryos derived by in vitro fertilization from THC exposed sperm had reduced 2-cell cleavage, 8-16 cell morula development, and reduced blastocyst development compared to unexposed sperm (46% vs. 33%). In conclusion, post-ejaculatory mammalian sperm exposure to THC compromises acrosome integrity, induces DNA damage, changes the sperm methylome, and reduces developmental potential. Collectively, these data implicate new considerations for recreational and clinical use of cannabis that impact cellular and molecular mechanisms important for sperm function with detrimental consequences for gamete interaction and embryo development.

BackgroundSchizophrenia is marked by impairments in emotional processing and social cognition, yet traditional neuroimaging paradigms often lack the ecological validity to capture these deficits in real-world contexts. MethodsIn this study, we used intersubject correlation (ISC) analysis of functional MRI data to examine shared neural representations of naturalistic visual narratives in individuals with schizophrenia and healthy controls. Participants viewed short films designed to evoke happy, sad, and emotionally neutral responses, allowing us to compare how synchronized brain activity varied with emotional content across and within groups. ResultsHealthy controls showed greater ISC in regions associated with affective salience, emotion recognition, and social understanding, including the amygdala, insula, and temporal cortices. In contrast, participants with schizophrenia displayed higher synchrony in visual, subcortical, and frontal areas, suggesting a reliance on perceptual and executive systems. To isolate the effects of emotion from general visual processing, we compared ISC during emotional clips relative to neutral videos. This revealed significantly reduced synchrony in the bilateral amygdala in patients, highlighting a core dysfunction in affective engagement. Interestingly, neutral stimuli elicited unexpectedly strong synchronization in frontal and limbic regions in the schizophrenia group, possibly reflecting altered salience attribution to ambiguous or emotionally ambiguous content. ConclusionsThese results point to a functional reorganization of affective processing in schizophrenia, where impaired limbic recruitment is accompanied by compensatory engagement of perceptual and cognitive control networks. ISC during naturalistic stimulation emerges as a powerful tool for capturing subtle disruptions in shared emotional experience in psychiatric populations.

Relapse-prevention strategies aimed at reducing relapse following abstinence, primarily focus on reducing cravings that lead to drug-seeking triggered by stress, drug-related cues, or re-exposure to the drug. Because addictive drugs form persistent associative contextual memories, we investigated how reactivation of cocaine-related hippocampal memories influences subsequent drug-seeking. Here, we tagged dorsal dentate gyrus (dDG) memory ensembles involved in encoding either a first or fourth cocaine exposure (15mg/kg, i.p) in male and female c57BL/6 mice using a TetTag approach. Mice underwent cocaine conditioned place preference (CPP), extinction, and reinstatement. We assessed whether optical reactivation of tagged cocaine-related ensembles could substitute for a cocaine priming injection to reinstate CPP, whether reactivation altered cocaine-induced reinstatement, and if these effects differed depending on stage of drug exposure. We also compared these effects to reactivation of saline-associated ensembles. Cocaine produced robust locomotor activation during conditioning, and sensitization developed across repeated drug exposures. Reactivation of a cocaine-related engram alone did not reinstate CPP. However, reactivation of the first cocaine exposure engram attenuated cocaine-induced reinstatement. In contrast, reactivation of the fourth exposure engram did not confer this protective effect. Interestingly, reactivation of saline-associated ensembles also reduced cocaine-induced reinstatement specifically in females, suggesting dDG ensemble reactivation may modulate relapse-related behavior through interference or neuromodulatory disruption of cocaine-associated representations, consistent with our prior work. These findings raise the possibility that early contextual experiences form competing or destabilizing representations that interfere with later cocaine-seeking when reactivated. Females also displayed greater sensitivity to locomotor-inducing effects of cocaine memory reactivation, although this was dissociated from CPP. Together, these findings show that cocaine memories are distinct across drug experience and selective reactivation of dDG engrams can differentially influence drug-seeking.

IntroductionThe anterior limb of the internal capsule (ALIC) is a major white matter highway connecting prefrontal cortical (PFC) regions to the thalamus, brainstem, and subthalamic nucleus. Structural and functional abnormalities within the ALIC circuit have been associated with many neuropsychiatric disorders, including obsessive-compulsive disorder (OCD) and depression, and deep brain stimulation (DBS) may provide effective treatment to some of these patients. However, it remains unclear whether the well-characterized topographic organization of the ALIC observed in healthy individuals and preclinical models is preserved in treatment-resistant psychiatric populations. MethodsWe first used diffusion tractography to evaluate the topography of PFC and subcortical fibers through the ALIC in patients with treatment-resistant OCD (n=18) and depression (n=5). In depression patients, we also evaluated ALIC topography using cerebro-cerebral evoked potentials (CCEPs) elicited by single-pulse electrical stimulation (SPES) of DBS leads in the ALIC and recordings in the ventral PFC (vPFC). ResultsThe topographic organization of PFC and subcortical projections is preserved in the ALIC among treatment-resistant psychiatric patients, consistent with patterns observed in healthy individuals and preclinical models. CCEP recordings in the ventral PFC showed a ventral ALIC to medial vPFC/dorsal ALIC to lateral vPFC response pattern in the left hemisphere, but not in the right. ConclusionOur findings confirm that topographic patterns within the ALIC previously identified using preclinical models and healthy controls are preserved in treatment-resistant psychiatric patients. Furthermore, by linking white matter topography to stimulation effects, this work supports more precise and individualized neuromodulatory strategies for neuropsychiatric disorders.

Background Cognitive impairment is a core feature of schizophrenia and a major determinant of functional disability. Executive deficits affect approximately 85% of patients and are associated with reduced activity in the prefrontal cortex (hypofrontality). Current pharmacological treatments show limited efficacy in improving cognition, highlighting the need for alternative therapeutic approaches. Combining non-invasive brain stimulation with cognitive remediation may enhance neuroplasticity and improve cognitive outcomes. Methods This prospective, randomized, double-blind, sham-controlled, parallel-group superiority clinical trial. A total of 120 adults aged 18-65 years with clinically stable schizophrenia diagnosed according to DSM-5 criteria will be enrolled at a single clinical center. Participants will be randomly assigned in a 1:1 ratio to receive either active transcranial direct current stimulation (tDCS) targeting the dorsolateral prefrontal cortex followed by cognitive remediation therapy (CRT) using the RehaCom system, or sham stimulation followed by the same cognitive training. Assessments will be conducted at three time points: prior to the intervention (V1), immediately after the intervention (V2), and during the follow-up visit 8 weeks after the intervention (V3). The primary outcome is change in cognitive performance measured with the CANTAB battery. Secondary outcomes include symptom severity assessed with the PANSS, global clinical status (CGI-S), and neurophysiological changes measured by EEG. Written informed consent will be obtained from all participants, and the study has received ethics committee approval. Discussion This trial will evaluate whether tDCS administered prior to cognitive training enhances cognitive improvement compared with cognitive training alone. The findings may inform the development of more effective interventions targeting cognitive deficits in schizophrenia. Trial registration ClinicalTrials.gov Identifier: NCT07273175. Registered on 25 November 2025.