Journal of Neuroscience Research

Background: Persistent neurological and cognitive symptoms following SARS-CoV-2 infection point to long-term alterations in brain structure and function. The thalamus, orbitofrontal cortex, and limbic networks are particularly susceptible to inflammatory and neurovascular stressors. However, the relationship between cortical, white-matter, and thalamocortical alterations in post-COVID syndrome remains unclear. Methods: 76 COVID-19 recovered participants (CRPs) and 51 healthy controls (HCs) underwent multimodal MRI comprising T1-weighted structural, diffusion, and resting-state functional acquisitions. Grey-matter morphology was assessed using voxel-based morphometry (VBM), white-matter microstructure using tract-based spatial statistics (TBSS), and thalamocortical functional connectivity (TC-FC) using seed-based analyses from major thalamic nuclei. Results were evaluated both across the groups (HC vs. CRP) and after stratifying CRPs by hospitalisation status (HC vs. Non-hospitalized patients (NHPs) vs. Hospitalized patients (HPs)). Results: No group-level grey-matter differences were observed between HCs and CRPs; however, HPs showed localized volume loss in the orbitofrontal and frontal-pole cortices (pFWE < 0.05). TBSS revealed widespread microstructural abnormalities, including reduced fractional anisotropy and mean diffusivity across association and commissural tracts (pcorr < 0.05), with regional increases in mode of anisotropy indicating selective loss of crossing fibres (pcorr < 0.05). Resting-state analyses revealed increased TC-FC from the mediodorsal thalamic nucleus to anterior cingulate, parietal, and occipital cortices (pcorr < 0.05), while differences in pulvinar and ventrolateral nuclei were not significant (pcorr > 0.05). Conclusions: Our findings indicate that COVID-19 recovery is associated with enduring alterations in fronto-limbic and thalamo-cortical circuits, most prominently in individuals with severe infection. Convergent structural and functional changes involving the orbitofrontal cortex and mediodorsal thalamus suggest network-specific reorganisation that may underpin persistent cognitive and affective symptoms of post-COVID syndrome.

2)BackgroundCircadian rhythm desynchrony (CD) occurs when there is a mismatch between the circadian clock and local time, such as shift work. Mouse models are commonly employed to study CD, but may have significant shortcomings such as environmental masking, a focus only on sleep physiology, and significant variability between study designs. ObjectiveThis study used in vivo telemetry for simultaneous, real-time monitoring of locomotor activity (LA), core body temperature (CBT), and brain activity (EEG) in freely moving C57BL/6J mice to assess CD effects. MethodsFour-month-old C57BL/6J mice (n=11) were surgically implanted with telemeters enabling simultaneous real-time recording of LA, CBT, EEG.: Mice were sequentially exposed to a control condition standard 12:12h light-dark cycle (T24) then 4, 8-day CD paradigms: 10:10 h short day (T20), social jet lag (SJL), repeated 6h phase advances (6A2), and a 3:3 h ultradian cycle (T6)For each paradigm, the final 48h of data (250 Hz) were analyzed. ResultsWe found clear differences in the severity of the effects of each CD paradigm on sleep and circadian fitness, where T20[~]T6>SJL>6A2. CBT revealed broader disruption, but EEG outputs proved the most sensitive indicators of internal desynchrony. ConclusionsEach CD paradigm produced a unique profile across behavioral, physiological, and neural domains. We have also identified Gamma CV as a novel, sensitive metric of CD. These results highlight the necessity of multimodal monitoring to accurately characterize the impact of ecologically relevant stressors on circadian and sleep physiology. Statement of SignificanceCircadian rhythm desynchrony (CD), driven by shift work, jet lag, and modern irregular light exposure, is a major health burden linked to metabolic, neurodegenerative, and neuropsychiatric diseases. However, standard methods for measuring CD in laboratory models often rely on simple locomotor activity, which can "mask" the true extent of internal circadian stress. In this study, we simultaneously monitored brain EEG activity, core body temperature, and motion across four distinct models of circadian stress. We discovered that locomotor activity is a deceptive indicator of health; while mice appeared to show no alterations under several stress paradigms, their brain waves and body temperatures revealed the underlying impact of CD. Specifically, we identified "Gamma CV" as a highly sensitive new brain-wave marker that detects early circuit instability even when behavior appears normal and sleep quantity is preserved. These findings provide a marker for identifying early neurological vulnerability to irregular light schedules, offering a potential bridge to understanding similar gamma brain-wave alterations seen in addiction, early-stage Alzheimers disease, and other disorders.

Abstract: BACKGROUND: Perivascular spaces (PVS), visible on brain MRI, contribute to the brain clearance system and are associated with age and neurodegenerative disorders. While lower volumes of PVS in the forebrains white matter and basal ganglia have been also demonstrated in preterm-born neonates, the long-term trajectory of PVS after premature birth remains unclear. This study tests for altered PVS volumes in very preterm/very low birthweight-born (VP/VLBW) adults compared to full-term controls and explores potential associations with cognitive performance. METHODS: PVS were assessed on T2-weighted MRI from 97 VP/VLBW and 89 full-term (FT) subjects at 26 years from the prospective, population-based Bavarian Longitudinal Study. PVS volume and count was based on automated nnU-Net-based segmentation. Regional PVS volumes were normalized by corresponding regional parenchyma volumes. Cognitive performance was assessed by the Wechsler Adult Intelligence Scale. MANCOVA was used for PVS group comparisons, Spearman rank correlations for testing PVS relationships with birth variables and cognitive scores. RESULTS: VP/VLBW-born adults showed significantly higher normalized PVS volumes in bilateral basal ganglia (p < 0.001, partial eta-squared = 0.096) and insula-related white matter (p = 0.001, partial eta-squared = 0.057). In the basal ganglia, higher PVS volumes were negatively correlated with gestational age (rho = -0.223, p = 0.030) and positively correlated with the Intensity of Neonatal Treatment Index (rho = 0.222, p = 0.030) in the VP/VLBW group. PVS volume was not associated with IQ scores. CONCLUSION: We demonstrate region-specific alterations of perivascular spaces in VP/VLBW-born adults. Data suggest that prematurity has lasting impact on the PVS.

Microglia are the brains resident immune cells that exhibit complex signaling behavior, including phagocytic activity in response to threats and prolonged neuronal activity. Adenosine triphosphate (ATP) is a chemoattractant for microglia. In the nucleus accumbens (NAc), ATP is co-packaged and released with DA, and microglia express dopamine (DA) receptors and ATP receptors. The present work examines microglia chemotactic motility for these transmitters using iontophoresis and multiphoton microscopy approaches in NAc brain slices from GFP-monocyte labeled transgenic mice. ATP chemoattraction was more regularly observed than DA chemoattraction, and DA chemoattraction occurred in only a small subset of microglia. The DA chemoattraction of this subset was blocked by DA D1 antagonism. Microglia are reactive oxygen species (ROS) scavengers. Application of glucose oxidase produces mild but consistent increases in ROS and induced inflammatory-related changes in microglial morphology and motility. Glucose oxidase application decreased DA release but had variable effects on ATP release. The toll-like receptor 4 (TLR4) agonist lipopolysaccharide (LPS) transitioned microglia from ramified to amoeboid morphology over a period of 4 hours, and increased DA and ATP release across this same period. These studies highlight the complex relationship between local immune activation and DA terminal functionality.

Early adversity increases vulnerability for adult psychopathology. Across multiple pre-clinical models of early adversity, there are reports of glial dysfunction and disrupted amino acid neurotransmission, along with maladaptive behavioral responses in adulthood. Disrupted G-protein coupled receptor signaling is known to phenocopy specific consequences of early life adversity. Enhanced Gq signaling in the forebrain excitatory neurons in early postnatal life programs anxio-depressive behaviors in adulthood, accompanied by altered neuronal glutamate and GABA metabolism in mouse models. We hypothesized that enhancing Gq signaling in forebrain excitatory neurons in early postnatal life may also impact glial function in adulthood. Our results show that postnatal hM3Dq-mediated chemogenetic activation of CaMKII-positive forebrain excitatory neurons not only increases anxiety-like behavior, but also evokes bidirectional transcriptional regulation of multiple glia-associated genes in the neocortex and hippocampi. While Gfap, Aldh1l1, S100{beta}, Eaat1, Eaat2 and Eaat3, mRNA levels were reduced in the neocortex, they were enhanced in the hippocampus, and a similar pattern was noted for GFAP protein levels. Transient, postnatal chemogenetic activation of CaMKII-positive neurons did not alter astrocyte cell density in both the neocortex and the hippocampus. Using (1H-(13C)) NMR spectroscopy, we observed a significant decline in astrocyte-specific glutamate and GABA neurotransmitter turnover, and a reduction in astrocyte metabolic flux within the neocortex and the hippocampus in adulthood in animals with a history of postnatal chemogenetic activation of forebrain excitatory neurons. Our findings indicate that chemogenetically driving Gq signaling transiently during the postnatal window in forebrain excitatory neurons results in persistent changes well into adulthood, with enhanced anxiety-like behaviors and disrupted glial function and metabolism, phenocopying specific changes in glial function noted following early adversity.

Alzheimers Disease and Related Dementias (ADRDs) are linked to reduced bone integrity and increased fracture risk, but the mechanisms that underlie this risk remain poorly defined. Current research suggests that environmental factors, such as diet, sleep, and light exposure can modulate the brain-bone axis, increasing susceptibility to bone loss and fractures. Circadian disruption (CD) associated with ADRDs may exacerbate the effects of disease and aging in the bone. In particular, regulation of bone marrow progenitors may be acutely susceptible to disruption along this axis. Here, we explore the interplay among genetic and environmental factors that influence bone structure, marrow progenitor cell activity, and monocyte-derived macrophages. The APP/PS1 transgenic mouse model (AP) is used as an in vivo model of amyloid-beta deposition. High-resolution micro-computed tomography (CT) identified sex- and genotype-specific responses in trabecular morphometry. Follow-up analysis with Raman spectroscopy (RS) found accumulation of non-enzymatic modifications of the organic matrix and notched three-point bending identified concomitant loss of bone toughness due to both CD and AP. Single-cell RNA sequencing (scRNA-seq) confirmed the presence of oxidative stress signals in the cellular populations of the bone marrow. We further mapped significantly differentially expressed genes (DEGs) from monocytes in the bone marrow to circadian-regulated proteins in monocyte-derived macrophages, revealing dysregulation of circadian timing in macrophages in vitro. These findings offer new insights into how environmental disruptions can exacerbate the progression of neurodegenerative disease and bone degradation. LAY SUMMARYPatients with Alzheimers disease have an increased bone fracture risk, but the biological link between brain and bone disease is not well understood. Everyday factors such as altered light exposure (shift work, screens late at night, etc.) can worsen outcomes in the brain and skeleton. Using a mouse model of Alzheimers disease, we found that both genetic risk and circadian disruption contribute to weaker bone and altered bone quality. We also identified inflammation and stress responses in bone marrow cells, suggesting that bone marrow may play a key role in linking brain disease to bone fragility.

Memory impairment is a common and sometimes overlooked feature of major depressive disorder, and cognitive deficits may precede the onset of depressive symptoms in some cases. However, the cognitive benefits of first-line treatments such as SSRIs are mixed. Tianeptine is an atypical antidepressant and cognitive enhancer that neither interacts with monoamine receptors nor inhibits the reuptake of their neurotransmitters. Its antidepressant efficacy in animal models requires activation of the mu-opioid receptor (mu-OR) and phosphorylation of the AMPA receptor. However, the receptors that mediate its memory enhancing actions have never been investigated. We therefore tested the ability of tianeptine to improve spatial memory in a cross-maze task in wild-type (WT) mice compared to its effects in mice with global knockout of either the mu-OR or delta-OR. In parallel, we assessed the effects of tianeptine on hippocampal oscillatory activity and spontaneous locomotion in the same genotypes. Adult male and female WT, mu -/-, and delta -/- mice on a C57BL/6J background were implanted with hippocampal electrodes for the recording of local field potential (LFP) oscillations. Consistent with our previous observations in anaesthetised rats, injection of tianeptine (10 mg/kg and 30 mg/kg SC) caused a dose-dependent increase in beta-frequency power in WT mice that was maximal at circa 25 Hz. The same effect was observed in delta -/- mice, but the increase in beta was completely absent in mu -/- animals. As others have reported previously, tianeptine also caused a mu-OR-dependent increase in spontaneous locomotor activity, but with a time-course that was distinct from the increase in beta power. Separate groups of WT, mu -/-, and delta -/- mice were tested for their ability to learn a food-rewarded spatial memory task in a cross-maze. Over a 20-day training period, sub-groups of each genotype received either tianeptine (10 mg/kg SC) or vehicle injection 30 min before testing. Tianeptine increased the percentage of correct trials and the number of allocentric (place) responses in WT mice, but did not enhance memory in either mu -/- or delta -/- mice, even though both genotypes were able to learn the task. These results indicate that the ability of tianeptine to drive hippocampal beta oscillations is dependent on the mu-OR, whereas its memory-enhancing actions require the presence of both mu- and delta-ORs. The latter result is consistent with the actions of tianeptine on postsynaptic AMPA receptors, and we are currently exploring the signalling pathways involved in this process.

Brain networks that support episodic memory development in the first years of life remain poorly understood. Protracted growth of regions such as the hippocampus have been suggested as a causal role in episodic memory development, but development of these memory brain networks and their role in episodic memory development is not yet fully elucidated. In this study, subcortical memory network regions (hippocampus, thalamus, amygdala) were segmented from MRI images in 835 visits spanning 0-4 years of age across 322 participants in the Baby Connectome Project. Hippocampal segmentations were further subdivided into head, body, and tail subregions manually for 426 visits, which were used to train models that automatically segmented hippocampal subregions for the remaining visits. 58 participants returned for an early school-age follow-up, including two episodic memory tasks. Volumetric growth trajectories differed across regions and across subregions within the hippocampus, with the head of the hippocampus showing steep growth that plateaued months later than the body or tail of the hippocampus. In the right hemispheres hippocampal head, age- and sex- adjusted volumes positively predicted future early school-age episodic memory performance. After accounting for total brain volume, the right thalamus also predicted memory performance. Total sleep duration at the follow-up visit accounted for performance variance above and beyond brain volume correlations. Altogether, results suggest that trajectories of growth and relationships between volume and episodic memory performance are region and subregion specific, and provide evidence for the important role of sleep in associations between brain networks and early episodic memory development. SignificanceThe hippocampus is a critical structure in episodic memory, yet precise longitudinal developmental trajectories of this structure have yet to be elucidated. This study provides detailed, subregion specific hippocampal trajectories, and demonstrates that variation in these trajectories is associated with variation in later episodic memory performance. This insight fills a current gap in the literature delineating how brain development and episodic memory behaviors are related in the first five years of life. Considering this is the same age range during which adults begin to have long-term memories available from childhood, this gap represents an important opportunity to understand how changes in the brain support the development of basic episodic memory skills.

Study ObjectivesSleep spindles are implicated in memory consolidation. Yet direct evidence linking spindle dynamics to declarative memory outcomes remains limited. We thus tested whether targeted memory reactivation (TMR) time-locked to sleep spindles enhances declarative memory, and whether the temporal organization of stimulated spindles-trains versus isolated events-is selectively associated with distinct memory outcomes. MethodsTwenty-eight healthy young adults learned image locations from two categories (animals, clothing) in a grid, each paired with a distinct auditory cue. During overnight NREM sleep, one cue was replayed time-locked to spindles detected in real-time using a closed-loop system (TMR condition); the other served as the non-reactivated control (No-TMR condition). Category-cue assignment was counterbalanced. Post-sleep recall, recognition accuracy, and movement time were assessed. ResultsRecall accuracy was significantly higher in the TMR than the No-TMR condition (93.96% vs. 90.61%, p = .024), whereas recognition accuracy (p = .139) and movement time (p = .651) did not differ. Stimulation intensity within spindle trains correlated with the TMR effect on recall (Spearman {rho} = .531, p = .004), whereas the proportion of isolated spindle stimulations correlated with the TMR effect on recognition ({rho} = .563, p = .002). Cross-associations were not significant. ConclusionsSpindle-locked TMR enhances recall-based declarative memory retention. The selective association between spindle temporal clustering and memory outcomes suggests that train-embedded and isolated spindles support different aspects of memory consolidation, highlighting spindle temporal context as a functionally relevant dimension of sleep-dependent memory processing.

Interval timing (IT) is the ability to time events in the range from seconds to a few minutes, allowing animals to organize behavior in time at short durations. IT relies on two cognitive functions: 1) Measuring the passage of time; 2) Storing and retrieving temporal memories in a context appropriate manner. The hippocampus (HC) and medial prefrontal cortex (mPFC) have been shown critical to the accuracy and precision of time-contingent instrumental responses in IT. The anatomy supporting mPFC-HC interactions, required for memory encoding and retrieval, include projections from HC to mPFC, and indirect bidirectional connections through the ventral midline thalamus (VMT), most notably reuniens. Here, we explored VMTs role in retrieving fixed-interval (FI) temporal memories. Rats were trained on a 5s FI signaled by an auditory cue and demonstrated temporal memory by poking predominantly at the time of the expected reward. Timing responses on individual trials were classified into on-time, early, and random response. Across sessions, random response trials decreased following training. Next, we switched training to longer intervals (20s or 80s; daily sessions for weeks). To probe the role of the VMT in temporal memory retrieval, we infused the GABAA-agonist muscimol, or saline, before training sessions. Results show that VMT muscimol infusions decreased timing precision. Also, at both intervals, the number of on-time response trials decreased, and the number of random response trials significantly increased. The number of early response trials had no significant change at 20s, and significantly decreased at 80s. Overall, our results suggest that the VMT is critical for precise retrieval of temporal memories. We also describe per-trial response patterns with characteristics consistent across all trained intervals, suggesting multiple behavioral strategies at play during interval timing.

Traumatic brain injury (TBI) is a condition of high incidence worldwide, but remains mostly undertreated. Previous observations in preclinical studies pointed to a beneficial effect of insulin-like growth factor 1 (IGF-1) in TBI. As brain injury is associated to loss of IGF-1 sensitivity, we tested the therapeutic potential of AIK3a305 (AIK3), a novel IGF-1 sensitizer. Twenty-four hours after mild TBI induced by controlled impact, mice received daily intraperitoneal injections of AIK3 during 4 weeks. We found that TBI-associated sensorimotor disturbances measured with the adhesive-removal test were reverted by AIK3 treatment. In addition, neurological and cognitive disturbances measured by the neurological severity score and Y maze respectively, were also ameliorated by treatment with the IGF-1 sensitizer, whereas increased anxiety after mild TBI was also normalized by AIK3. Circulating levels of IGF-1 were increased after AIK3 treatment in TBI mice, while serum IL-6 levels, a biomarker of inflammation associated to TBI were similar to control mice treated with AIK3. Transcriptomic analysis determined that treatment with AIK3 widely affected gene expression in TBI brains, showing a general reduction in both up- and down-regulated genes. Collectively, these data support the use of IGF-1 sensitizers such as AIK3 for treatment of TBI.

Elite athletes exhibit sport-specific neural adaptations, yet it remains unclear whether such changes reflect general effects of training or the unique demands of individual sports. Skiing requires postural control and whole-body coordination under dynamically unstable environments, placing high demands on somatosensory processing and sensorimotor integration. The present study aimed to identify structural brain characteristics specific to elite skiers by comparing them with athletes from other sports disciplines and non-athletes. T1-weighted MRI data were analyzed using voxel-based morphometry in 13 skiers, 23 non-ski control athletes and 25 non-athletes. Whole-brain analysis comparing skiers with non-ski athletes revealed a significant cluster showing greater gray matter volume in skiers compared with non-ski athletes in the left postcentral gyrus, extending into the superior parietal lobule. The identified cluster primarily encompassed cytoarchitectonic Areas 2 and 5L. These regions are involved in higher-order somatosensory processing and multisensory integration. Importantly, region-of-interest analysis demonstrated that gray matter volume within this cluster was greater in skiers compared with non-ski athletes and non-athletes, with no difference between non-ski athletes and non-athletes. These findings highlight the relative prominence of structural adaptations within somatosensory-parietal networks, reflecting the unique integration of proprioceptive and other sensory information required for elite skiing. Overall, these findings provide evidence for sport-specific structural brain differences in elite athletes and highlight the importance of somatosensory and parietal regions in sensorimotor integration relevant to skiing. These findings may have implications for understanding neural markers of expertise and may inform future approaches to training and performance evaluation in skiing.

The impact of microglia antigen presentation on CNS infiltrating CD8 T cells responses during neurotropic virus infection has been difficult to define. Using Theilers murine encephalomyelitis virus (TMEV) infection of neurons as a model system, our laboratory has previously determined that H-2Db restricted, but not H-2Kb restricted CD8 T cells are required for viral clearance, demonstrating the role of discrete MHC class I alleles. To determine the extent microglia antigen presentation impacts brain-infiltrating CD8 T cells, our laboratory generated novel single MHC class I conditional knockout mice in which H-2Kb or H-2Db can be specifically deactivated in TMEM119+ microglia with tamoxifen administration. During TMEV infection, conditional knockout of H-2Kb in microglia reduced antigen-specific CD8 T cell proliferation in the brain. Meanwhile, mice with deletion of Db in microglia had reduced levels of perforin in antigen-specific CD8 T cells. Furthermore, microglia specific deletion of H-2Db reduced CD8 T cell numbers in the brain and preserved blood-brain barrier (BBB) integrity. Microglial Db restricted antigen presentation was also essential for the reactivation of CD8 tissue resident memory (TRM) cells and BBB integrity during memory recall responses. These findings further our understanding of how brain infiltrating antiviral CD8 T cell responses are impacted by microglia, as well as define how this cellular interaction contributes to BBB disruption during neuroinflammation. These findings also have high significance to our understanding of how microglia impact CD8 TRM cell populations that reside in the brain long after virus infection is cleared. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=111 SRC="FIGDIR/small/722741v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@9302a9org.highwire.dtl.DTLVardef@193b5f4org.highwire.dtl.DTLVardef@8eb036org.highwire.dtl.DTLVardef@1d2cd6a_HPS_FORMAT_FIGEXP M_FIG C_FIG

Perinatal hypoxia is a major contributor to neurodevelopmental disorders; however, the consequences of mild-to-moderate perinatal hypoxia (MPH) remain insufficiently characterized. Here, we investigated cortical plasticity following MPH using a multimodal approach that combines behavioral assessment, histological analysis, and in vivo magnetic resonance imaging (MRI). Fifty-six Wistar Han rats were exposed to hypoxia or normoxia at postnatal day 1 (P1). Neurodevelopmental assessment from P3 to P14 revealed impaired rooting and vibrissae-placing reflexes in hypoxic rats. Histological analysis demonstrated: altered expression of microtubule-associated protein-2, apical dendrite bundling, reduced neurofilament-H expression, and decreased dendritic arbor complexity in large pyramidal neurons, indicating disrupted maturation of excitatory circuits. Increased parvalbumin expression, higher interneuron density, and its enhanced neurite elaboration indicated precocious development of inhibitory circuits, consistent with a compensatory response. MRI at P15, combined with whole-brain voxel-wise analysis, revealed a significant increase in fractional anisotropy in the anterior cingulate cortex (ACC). Convergent behavioral, histological, and imaging findings identified the ACC as the most vulnerable region following MPH, followed by the somatosensory cortex. These findings reveal early cytoarchitectural and MRI detectable correlates of a single episode of MPH, which, together with previous findings from this model, support the neurodevelopmental origin of persistent alterations in cortical structure and circuit function, characterized by an excitatory-inhibitory imbalance. The study identifies and defines a framework for understanding region-specific vulnerability and plasticity in the immature brain, with implications for improving the early detection of subtle perinatal brain injury, as a prerequisite for timely therapeutic intervention.

Individuals with Fetal Alcohol Spectrum Disorders (FASDs) show reduced subicular volume, and preclinical studies compliment this by demonstrating that third-trimester-equivalent ethanol exposure induced apoptosis in corticolimbic regions, including the subiculum. The subiculum mediates hippocampal-cortical communication critical for long-term memory consolidation. Within the distal dorsal subiculum, a population of bursting neurons uniquely express VGLUT2 and they play a key role in memory processing. We hypothesized that third-trimester-equivalent ethanol exposure would reduce neuronal and VGLUT2+ cell density in the dorsal subiculum and reduce the excitability of bursting neurons, providing a mechanism for long-term memory impairments observed in FASD. To test this, postnatal day (P)7 mice received a subcutaneous injection of ethanol and long-term effects were assessed in adolescence (P35-62). Using transgenic mice with fluorescently labeled VGLUT2+ neurons, and immunohistochemistry we observed a significant reduction in neuronal density in males and an increase in VGLUT2+ cell density in females. Using whole-cell patch clamp electrophysiology, we observed a reduction in action potentials per burst in both sexes. Additionally, females showed reduced overall excitability, and a subset of neurons exhibited a shift to regular spiking. These findings suggest that development ethanol exposure disrupts subicular output by impairing burst firing, potentially weaking hippocampal-cortical communication and contributing to the cognitive deficits associated with FASD. HighlightsO_LIThird-trimester ethanol targets VGLUT2+ neurons in the dorsal subiculum C_LIO_LIEthanol reduced neuronal density in male dorsal subiculum C_LIO_LIEthanol increases VGLUT2+ cell density in females C_LIO_LIEthanol reduces action potential per burst in both sexes C_LIO_LIFemales show reduced excitability and loss of bursting in some cells C_LI

BackgroundMicroglial heterogeneity is a fundamental feature of brain homeostasis and pathology. The purpose of this study was to investigate the complexity of microglial plasticity by characterizing specialized oligodendrocyte-like microglial subsets. MethodsThe study was performed utilizing single-cell transcriptomics analyses and immunofluorescence staining to identify and profile microglial subpopulations. Additionally, spatial transferring and morphological analyses were conducted to determine the anatomical distribution and structural features of these specific cells. ResultsWe identified a distinct microglial subset termed dual-phenotype microglia (DPM), which co-expresses microglial and oligodendrocyte markers. DPM consisted of two subtypes with distinct functions: myelin-associated DPM (mDPM) and neuron-associated DPM (nDPM). Spatial and morphological evaluations revealed that mDPMs were sparsely distributed across the whole brain and exhibited a highly ramified architecture, whereas nDPMs were enriched in the hippocampal dentate gyrus. Mechanistically, we found that mDPM function was driven by the Sox10 regulon to modulate myelin maintenance and axonal ensheathment, while nDPM was orchestrated by Glis2, facilitating essential neuron-glia crosstalk and synaptic regulation. Furthermore, we demonstrated that nDPM and mDPM were predicted to undergo significant alterations in multiple sclerosis and Alzheimers disease. Notably, mDPMs were selectively enriched in active multiple sclerosis lesions, revealing that DPM were closely related to neuropsychiatric disorders. ConclusionsBy comprehensively characterizing the morphology, molecular signatures, and spatial logic of these oligodendrocyte-like microglial subsets, our study elucidated the complexity of microglial plasticity. These findings provided new insights into their diverse roles in central nervous system health and disease. Graphical abstractIdentification, Molecular Profiling, and Functional Modeling of Dual-Phenotype Microglia (DPM). (1) Discovery: Identification of the dual-phenotype microglia (DPM) population through single-cell transcriptomics. (2) Molecular Signatures: The transcriptomic identity of DPM subtypes is governed by specific regulatory networks. (3) Distribution & Pathology: Spatial mapping reveals divergent anatomical logic and disease relations for DPM subtypes. (4) Mechanism/Theory: A proposed functional model of mDPMs as "metabolic relay" and support units. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=113 SRC="FIGDIR/small/724239v2_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@b7db1dorg.highwire.dtl.DTLVardef@9265e7org.highwire.dtl.DTLVardef@1605d82org.highwire.dtl.DTLVardef@19b048f_HPS_FORMAT_FIGEXP M_FIG C_FIG

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.

BackgroundSleep-onset insomnia (SOI) is characterized by difficulty initiating sleep and is frequently associated with psycho-affective disorders. Despite its high prevalence and clinical impact, pathophysiological biomarkers and clear nosological frameworks remain lacking. Conventional polysomnographic (PSG) measures provide limited insight into the continuous dynamics of vigilance during the transition from wakefulness to sleep and across the night. MethodsWe retrospectively analyzed PSG recordings from 2 952 individuals using fine-grained EEG markers of vigilance, including theta/alpha ratio dynamics, micro-sleep episodes, and probability-of-wakefulness metrics. Individuals with and without SOI were compared, and SOI subgroups with and without depressive or anxiety symptoms were further examined. ResultsIndividuals with SOI exhibited a persistent state of elevated EEG-defined vigilance extending from wakefulness through the sleep onset period (SOP) and across all sleep stages, including N2, N3, and REM sleep. This hypervigilance was associated with vigilance instability during the SOP and a delayed accumulation of deep sleep over the night. Importantly, hypervigilance was more pronounced in isolated SOI than in SOI comorbid with psycho-affective symptoms, particularly depressive symptoms, and remained largely undetected by conventional PSG macrostructure measures. ConclusionsThese findings support a reconceptualization of SOI as a disorder of sustained vigilance dysregulation and reveal heterogeneity in hypervigilance across insomnia phenotypes. This dissociation from psycho-affective symptoms challenges current nosological frameworks at the interface of sleep and psychiatric disorders. By capturing microstructural alterations in vigilance invisible to standard scoring, continuous EEG-based markers provide mechanistic insight into insomnia heterogeneity and may enable biologically informed phenotyping across psychiatric conditions.

Benzo[a]pyrene (BaP), a representative polycyclic aromatic hydrocarbon (PAH), is a widespread environmental toxicant and potent ligand of the aryl hydrocarbon receptor (AHR). Yet, how early developmental exposure to BaP influences human neurodevelopment remains poorly understood. We first examined AHR expression dynamics during human embryonic stem cell (ESC)-derived cerebral organoid development and found that AHR expression was highest at the ESC stage and declined during subsequent differentiation, suggesting a potential window of heightened susceptibility to AHR-mediated environmental perturbations. Based on this observation, ESCs were exposed to BaP (0.1, 1 M) for 7 days prior to organoid generation. BaP exposure did not alter proliferation, cell death, or global transcription of ESCs but increased expression of a subset of AHR target genes. Remarkably, however, organoids derived from BaP-exposed ESCs exhibited profound morphological defects resulting from premature neurogenesis, characterized by disrupted neural rosette organization, reduced EOMES intermediate progenitors, and increased BCL11B neurons. Pharmacological inhibition of AHR with CH-223191 attenuated AHR activation and rescued the progenitor-neuron imbalance. These findings identify AHR signaling as a critical upstream mediator of BaP-induced developmental neurotoxicity and highlight the vulnerability of early pluripotent stages to environmental insults.

IntroductionMalaria is still a pressing global health challenge, especially in sub-Saharan Africa, where behavioral factors such as alcohol consumption may exacerbate its impact. The present study is aimed at investigating the pathogenesis of alcohol-exacerbated malaria in Plasmodium berghei-infected an animal model (mice). MethodsMale mice were separated into four treatment groups: control, alcohol control, P. berghei and P. berghei plus acute alcohol treatment groups. Animals were infected with malaria through intraperitoneal injection of P. berghei and an acute dose of ethanol (20% v/v) was introduced 48 hours post-infection. Parasitaemia was monitored using the Giemsa-stained thin blood smears. Haematological parameters were assessed using automated blood analyser. Liver function was evaluated by measuring serum levels of AST and ALT and cytokine profiles (TNF-, INF-{gamma}, IL-6, IL-1{beta}) were quantified using ELISA kits. ResultsResults show that acute alcohol intake led to a significant increase in parasitaemia in the P. berghei group (p<0.01). Haematological analysis revealed a significant (p<0.001) reduction in RBC count, haemoglobin levels, haematocrit percentage, platelet count and others in the P. berghei plus acute alcohol group. Liver enzyme assays revealed an elevated AST and ALT levels (p<0.001) in the P. berghei group. Cytokine analysis revealed a significant (p<0.01) upregulation of pro-inflammatory cytokines (TNF- INF-{gamma}, IL-1{beta} and IL-6), due to acute alcohol. These results suggest that alcohol exacerbates malaria pathogenesis by increasing parasitaemia, promoting immune dysregulation and liver injury, mediated by a shift toward a pro-inflammatory cytokine profile.