bioRxiv Subject Collection: Neuroscience's Journal

Cell cycle dysregulation contributes to neurodegeneration in humanneurons from ALS/FTD-related C9orf72 repeat expansion carriers.
The C9orf72 hexanucleotide repeat expansion GGGGCC (G4C2) cause the most common genetic forms of ALS and frontotemporal dementia, affecting thousands of patients worldwide with uniformly fatal outcomes. C9orf72 ALS/FTD patients lack targeted treatments because druggable molecular vulnerabilities remain unidentified. Using iPSC-derived motor neurons from C9orf72 carriers and age-matched controls, we performed comprehensive cell cycle analysis, drug screening, and single-nucleus RNA sequencing validation in human brain tissue. C9orf72 neurons exhibit age-dependent cell cycle reentry with increased S-phase cells, elevated cyclin and CDK expression, and aberrant cell cycle gene signatures confirmed in patient brain excitatory neurons. Mechanistically, arginine-containing dipeptide repeat proteins (poly-GR, poly-PR) drive this cell cycle activation through CDK4/6 pathway stimulation, while C9orf72 loss-of-function alone shows no effect. Critically, the FDA-approved CDK4/6 inhibitor palbociclib normalizes cell cycle progression, reduces S-phase entry, and rescues neuronal survival with significant reduction in motor neuron death. Single-nucleus RNA-sequencing analyses from C9orf72 patient cortex reveals cell cycle-activated neuronal subclusters. Copy number variation, gene ontology and pathways analyses revealed alterations in DNA repair pathways, cell cycle regulation and cell cycle transition, validating our in vitro findings. These results identify cell cycle dysregulation as a therapeutic target in C9orf72 ALS/FTD with clinical translation potential using existing therapeutics.

Glycated alpha-synuclein assemblies cause distinct Parkinsons disease pathogenesis in mice
Alpha-synuclein (-Syn) misfolding and aggregation are key drivers of Parkinsons disease (PD) pathology. Mutations and certain post-translational modifications impact its aggregation propensity and pathogenicity. Glycation, a non-enzymatic modification enhanced during hyperglycemia and aging, both known risk factors for PD, has been implicated in -Syn pathology. Although preformed -Syn-fibrils induce PD-like phenotypes in mice, the impact of glycation on their pathogenicity is unclear. In the current study, we glycated -Syn using methylglyoxal (MGO), a potent glycating agent, resulting in altered biophysical characteristics in comparison to non-glycated -Syn. Glycation inhibited the formation of typical beta sheet structures under aggregating conditions. Despite that, glycated -Syn assemblies induced dopaminergic neurodegeneration and neuroinflammation to a similar extent as the non-glycated -Syn fibrils upon their injection in the mouse substantia nigra (SN). However, these glycated assemblies triggered higher neuroinflammation and increased accumulation of receptors for advanced glycation end products (RAGE) compared to non-glycated fibrils. Consequently, an earlier onset of neuromuscular deficits and anxiety was observed in these mice. Thus, glycation of -Syn causes distinct PD-associated pathology compared to non-glycated -Syn, causing an earlier onset of motor symptoms. These findings provide insight into how glycation of -Syn due to hyperglycemia may contribute to an increased risk of PD in diabetic populations.

Neurotrophic Factor-α1/carboxypeptidase E regulates critical protein networks to rescue neurodegeneration, defective synaptogenesis and impaired autophagy in Alzheimer's Disease mice
Background The global aging population is increasingly inflicted with Alzheimer's disease (AD), but a cure is still unavailable. Neurotrophic Factor-1/carboxypeptidase E (NF-1/CPE) gene therapy has been shown to prevent and reverse memory loss and pathology AD mouse models However, the mechanisms of action of NF-1/CPE are not fully understood. We investigated if a non-enzymatic form of NF-1/CPE-E342Q is efficient in reversing AD pathology and carried out a proteomic study to uncover the mechanisms of action of NF-1/CPE in AD mice. Methods AAV-human NF-1/CPE and a non-enzymatic form, NF-1/CPE -E342Q were delivered into hippocampus of 3xTg-AD mice and effects on cognitive function, neurodegeneration, synaptogenesis and autophagy were investigated. A quantitative proteomic analysis of hippocampus of 3xTg-AD mice with and without AAV-NF-1/CPE treatment was carried out. Results Hippocampal delivery of AAV-NF-1/CPE-E342Q prevented memory loss, neurodegeneration and increase in activated microglia in 3xTg-AD mice, indicating its action is independent of its enzymatic activity. Quantitative proteomic analysis of hippocampus of 3xTg-AD mice that underwent NF-1/CPE gene therapy revealed differential expression of >2000 proteins involving many metabolic pathways. Of these, two new proteins down-regulated by NF-1/CPE: Nexin4 (SNX4) and Trim28 which increase A{beta} production and tau levels, respectively were identified. Western blot analysis verified that they were reduced in AAV-NF-1/CPE treated 3xTg-AD mice compared to untreated mice. Our proteomic analysis indicated synaptic organization as top signaling pathway altered as a response to CPE expression. Synaptic markers PSD95 and Synapsin1 were decreased in 3xTg-AD mice and were restored with AAV-NF-1/CPE treatment. Proteomic analysis hypothesized involvement of autophagic signaling pathway. Indeed, multiple proteins known to be markers of autophagy were down-regulated in 3xTg-AD mice, accounting for impaired autophagy. Expression of these proteins were upregulated in 3xTg-AD mice with NF-1/CPE gene therapy, thereby reversing autophagic impairment. Conclusions This study uncovered vast actions of NF-1/CPE in restoring expression of networks of critical proteins including those necessary for maintaining neuronal survival, synaptogenesis and autophagy, while down-regulating many proteins that promote tau and A{beta} accumulation to reverse memory loss and AD pathology in 3xTg-AD mice. AAV-NF-1/CPE gene therapy uniquely targets many metabolic levels, offering a promising holistic approach for AD treatment.

An Integrated In Vitro Platform and Biophysical Modeling Approach for Studying Synaptic Transmission in Isolated Neuronal Pairs
Studying synaptic transmission and plasticity is facilitated in experimental systems that isolate individual neuronal connections. We developed an integrated platform combining polydimethylsiloxane (PDMS) microstructures with high-density microelectrode arrays to isolate and record single neuronal pairs from human induced pluripotent stem cell (hiPSC)-derived neurons. The system maintained hundreds of parallel neuronal pairs for over 100 days, demonstrating functional synapses through pharmacological validation and long-term potentiation studies. We coupled this platform with a biophysical Hodgkin-Huxley model and simulation-based inference to extract mechanistic parameters from electrophysiological data. The analysis of long-term potentiation stimulation using a biophysical model revealed (-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) AMPA and (N-methyl-D-aspartate) NMDA receptor-specific alterations, providing quantitative insights into synaptic plasticity mechanisms. This integrated approach represents the first system combining isolated synaptic pairs, long-term stability, and mechanistic modeling, offering unprecedented opportunities for studying human synaptic function and plasticity.

Selective transcriptomic recovery by (2R,6R)-hydroxynorketamine in opioid-abstinent mice: Machine learning identifies predictive biomarkers
Background: Opioid abstinence induces persistent emotional disturbances and widespread neuroplastic changes, in areas of the brain including the hippocampus. Although ketamine and its metabolite (2R,6R)-hydroxynorketamine (HNK) show potential in reversing opioid abstinence-related deficits in rodents, the molecular mechanisms underlying their efficacy remain poorly understood. Methods: Male C57BL/6J mice underwent a 3-week opioid abstinence paradigm, followed by a single (2R,6R)-HNK (10 mg/kg, i.p.) or saline injection on day 28. Sucrose and social preference tests were used to assess behavioral deficits. We conducted RNA sequencing of ventral hippocampal tissue from these mice, followed by differential gene expression and functional enrichment analyses. Additionally, Random Forest machine was applied to identify predictive differentially expressed genes (DEGs) associated with (2R,6R)-HNK treatment response. Results: Transcriptomic analysis identified 206 DEGs in morphine-abstinent mice without treatment compared to opioid-naive controls (MOR-SAL vs. SAL-SAL), implicating altered immune signaling, synaptic function, and structural plasticity. Comparison of opioid-abstinent mice treated with (2R,6R)-HNK to opioid-naive controls (MOR-HNK vs. SAL-SAL) revealed 186 residual DEGs, enriched for Th17-mediated immune and fear regulation pathways, suggesting a persistent intermediate molecular phenotype despite normalized behavioural scores. DEGs overlap analysis between MOR-HNK vs. MOR-SAL and MOR-SAL vs. SAL-SAL groups indicated that (2R,6R)-HNK treatment reversed 55 DEGs in opioid-abstinent mice, including Transthyretin (Ttr) and T-cell surface glycoprotein (Cd5) expression levels. Machine learning identified interleukin 1 receptor accessory protein-like 1 (Il1rapl1) and cytotoxic T lymphocyte-associated protein 2 beta (Ctla2b) as top predictors of (2R,6R)-HNK's treatment response. Notably, while (2R,6R)-HNK induces transcriptional changes in opioid-naive mice (SAL-HNK), it does not affect behavior compared to untreated controls (SAL-SAL). In contrast, its therapeutic effects are evident in morphine-abstinent mice (MOR-HNK), highlighting its context-dependent efficacy. Conclusion: (2R,6R)-HNK promotes both transcriptional and behavioral recovery in opioid-abstinent mice, reversing key gene expression changes. However, persistent dysregulation of neuroimmune and emotion-related pathways suggests an intermediate molecular state, reflecting ongoing recovery.

Biliverdin Reductase A is a major determinant of neuroprotective Nrf2 signaling
Biliverdin reductase A (BVRA), the terminal enzyme in heme catabolism, generates the neuroprotective and lipophilic antioxidant bilirubin. Here, we identify a novel non-enzymatic role for BVRA in redox regulation. We show that BVRA directly interacts with nuclear factor erythroid-derived factor-like 2 (Nrf2), the master regulator of redox homeostasis, to modulate target signaling pathways. ChIP-seq and RNA-seq analyses reveal that this interaction coordinates the expression of neuroprotective genes that are typically dysregulated in Alzheimers disease and other neurodegenerative conditions. Thus, this previously unknown BVRA-Nrf2 axis controls an essential pathway of redox signaling in neuroprotection. Our findings establish BVRA as a dual-function integrator of antioxidant defenses in both the lipophilic and hydrophilic subcellular compartments, bridging these two distinct and critical cellular protection mechanisms in the brain. This advancement in understanding the endogenous antioxidant system of the brain positions the BVRA-Nrf2 axis as a promising therapeutic target for neurodegenerative disease.

Microscale dysfunction and mesoscale compensation in degenerating neuronal networks
Progressive neurodegenerative diseases involve neuronal dysfunction from cellular to circuit to whole-brain levels, but complexity and variability, both between and within diseases, pose significant research challenges. However, although they are differentiated by anatomical origins, vulnerable neuronal subtypes, and specific misfolded proteins, neurodegenerative diseases also share many important features. During presymptomatic disease phases, neural networks initiate multiple compensatory processes to maintain network function, including increased network centralisation and reliance on a rich-club of hub nodes, which have been proposed as common reconfigurations to neural network damage. Currently, while supporting evidence for such mechanisms has been found in some neurodegenerative diseases, it is limited in others, like ALS. This knowledge gap makes it challenging to ascertain if there are indeed common pre-symptomatic mechanisms within and across different neurodegenerative diseases. To address this, we investigated the structural and functional properties of ALS patient derived motor neuron networks and counterpart networks from a healthy donor using longitudinal multielectrode array recordings and graph theory-based network analysis. We demonstrate microscale-level motor neuron dysfunction, including TDP-43 proteinopathy, hyperactivity and reduced spike amplitude. Structurally, we observed neurite hypertrophy, indicating that degenerating networks attempt to establish new connections. We furthermore document mesoscale-level functional reconfigurations, including increased rich-club connectivity and network assortativity, indicating functional compensation in ALS where networks become more centralised to maintain computational capacity. We thus provide novel evidence that ALS networks become increasingly centralised, which places progressively mounting demands on a rich-club, predisposing networks to further damage, consistent with existing models of common reconfigurations in neurodegenerative disease.

Visual blur disrupts the kinematic and temporal aspects of reach-grasp-lift movements.
Degraded vision (caused by pathological reasons or monocular viewing) has been shown to affect fine motor control. However, there is a dearth of work examining the effects of "cataract-like" blur on reach-to-grasp performance. There is, however, a trend towards amblyopic blur being associated with deficits in reach-to-grasp performance, suggesting that timely intervention in treating cataracts is likely to be essential to maintain a functional ageing population. 18 participants performed a reach-to-grasp task. They reached for and precision grasped high and low-contrast cuboid targets under three visual conditions: binocular blur, monocular blur (full vision in the other eye) and full vision. They also performed contrast sensitivity, stereoacuity and visual acuity tests. Visual blur was associated with changes to the kinematics of prehensile movements' early/acceleration stage (maximum acceleration and maximum velocity) and maximum grip aperture. Visual blur also caused the period from first contact with the target to the time it was lifted (dwell time) to be elongated. These results suggest that changes in prehension associated with visual blur are linked to differences in the planning and online control of prehension movements.

Defining a functional hierarchy of millisecond time: from visual stimulus processing to duration perception
In humans, the neural processing of millisecond time is associated with the activation of a wide range of brain areas and involves different types of neural responses. Unimodal tuning to stimulus duration, for example, has been observed in some of these areas but not in others, and its presence is either inconsistently reported or appears redundant along the cortical hierarchy. Moreover, how this duration tuning supports different functions or perception remains unclear. To address these questions, we measured brain activity with ultra-high field (7T) functional Magnetic Resonance Imaging (fMRI) while participants performed a visual duration discrimination task. Using neuronal-based modeling we estimated unimodal responses to visual durations across a multitude of cortical areas defined with high anatomical precision. In the parietal and premotor cortices, and the caudal portion of the supplementary motor area (SMA), we observed neuronal populations tuned to the full range of presented durations, spatially clustered in well-defined maps. In contrast, in the rostral SMA, inferior frontal cortex, and anterior insula, neuronal units showed duration preferences centered around the mean of the presented duration range. This preference also correlated with the perceptual boundary participants used to solve the task. Differences in preference, spatial clustering, and behavioral correlation suggest distinct functional roles for these cortical areas -ranging from abstract duration representations for readout and task-related goals in the parietal and premotor cortex, to more categorical and subjective representations in the insula and inferior frontal cortex. In line with these hypothesized roles, we also observed distinct patterns of correlation in duration preferences across these cortical regions. Overall, our findings provide a framework for a more comprehensive understanding of the neural circuits and mechanisms underlying duration processing and perception in vision.

Left Area PF as a Neural Marker of Technical Reasoning
Humans possess a unique capacity for technical reasoning - the ability to infer and manipulate the causal structure of the physical world. Although this faculty is central to technological innovation, its neural substrates remain incompletely understood. Here, we show that grey matter volume in the left cytoarchitectonic area PF, within the supramarginal gyrus of the inferior parietal lobule, selectively predicts and accurately classifies technical reasoning performance in healthy adults (N = 75; 54 females; mean age = 20.92 +- 3.28 years). This association persists independently of demographic factors, personality traits, and total brain volume. By contrast, grey matter volume in right prefrontal regions, examined as control areas, correlates with broader cognitive functions - namely, fluid intelligence and abstract reasoning, but not with technical reasoning. These findings support the hypothesis that the left area PF is a domain-specific substrate for technical reasoning. Situated within a parietal territory that is evolutionarily expanded in humans, this region may constitute a neural signature of the human capacity to understand and reshape the material world.

Comparative chemosensory mechanisms underlying larval foraging and competitive advantage in Aedes albopictus and Aedes aegypti
The invasive Asian tiger mosquito, Aedes albopictus (Skuse), and yellow fever mosquito, Aedes aegypti (L.) are known to compete for resources during the larval stage, often resulting in the ecological displacement of Ae. aegypti by Ae. albopictus. The chemosensory system plays a pivotal role in larval foraging behavior and may contribute to the competitive advantage. Here, we employed comparative transcriptomics and functional characterization of odorant receptors (ORs) to investigate species-specific differences in larval olfaction. Notably, we uncovered functional variation within the conserved olfactory indole receptor clade, indicating distinct ecological adaptations across species and life stages. We also developed a novel approach to functionally characterize the larval sensory cone and mapped its receptor neuron projections to two key brain regions: the antennal lobe and the subesophageal ganglion. This study provides new insights into the molecular and neural basis of chemosensory-driven behavior in mosquito larvae and highlights the potential role of olfaction in shaping interspecies competition and ecological success.

UNWANTED AXON GROWTH: PTEN AND THE SUPPRESSION OF AXON PLASTICITY IN ADULT NERVES
In adults, peripheral nerves comprise bundles of disseminated motor, sensory and autonomic axons that are considered stable neuroanatomical units. The only exceptions to this established wiring are very distal terminal branches in target organs, such as skin. Here we provide a remarkable deviation from this state of affairs in the peripheral nerves of mice with a conditional knockout of sensory neuron PTEN (phosphatase and tensin homolog deleted on chromosome ten). PTEN is normally expressed in adult sensory neurons, particularly small IB4 nonpeptidergic subtypes and its knockdown after injury or during experimental diabetes improves axon regrowth. We studied Advillin Cre;PTEN null mice lacking PTEN in their sensory neurons. As might be expected, their harvested and cultured DRG neurons displayed enhanced neurite outgrowth in vitro. In vivo, these mice were healthy and had a normal sensory behavioural phenotype. However, the nerves of mice lacking sensory neuron PTEN were highly abnormal, with augmented clusters of small myelinated and unmyelinated axons populating endoneurial fascicles of their peripheral nerve trunks. The axon clusters did not disrupt normal fascicular anatomy but invested the epidermis with greater axon numbers. Within endoneurial fascicles, supernumerary axons formed regenerative units and expressed ongoing growth markers, unlike normal adult axons. This was not accompanied by rises in dorsal root ganglia (DRG) neuron numbers, indicating enhanced distal sprouting from parent neurons. Additionally, sprouting axons were electrophysiologically intact, generating rises in the amplitudes of sensory nerve action potentials. Despite this extensive regenerative activity of intact nerves, regeneration indices after superimposed injury were only modestly enhanced or unchanged. This unusual behaviour of adult sensory axons lacking a single growth-suppressive molecule may identify insights into what molecular constraints the nervous system normally utilizes to suppress inappropriate plasticity.

Gut miRNA regulates gut microbiome and Alzheimer pathology in App-knock-in mice
Alzheimer's disease (AD) alters the gut microbiome. It remains unclear whether manipulation of miRNA could modulate the gut microbiome and AD pathologies. Depletion of gut miRNA in App-knock-in mice by conditional knockout of Dicer1 gene in intestinal epithelial cells: 1) decreased the absolute number and changed the composition of bacteria in both the gut and brain; 2) reduced cerebral A{beta} load by inhibiting {beta}-secretase activity and increasing the expression of LRP1 and ABCB1 at the blood-brain barrier; 3) increased Il-10 transcription and decreased the transcription of Ccl-2 gene, and that of Ndufa2 and Ndufa5 genes encoding mitochondrial respiratory enzymes in the brain; and 4) induced anxiety symptoms without affecting cognitive function in AD mice. Thus, manipulating miRNA in the gut can modify AD pathogenesis. Future studies should focus on identifying AD-specific miRNAs in the gut that can be therapeutically exploited (e.g. by oral administration) to prevent the progression of AD.

Reduced inhibition, bursting, and accelerated oscillations drive early hippocampal hyperactivity in Alzheimer's disease
'Early hippocampal hyperactivity' is a well-documented yet poorly defined phenomenon in Alzheimer's disease (AD). While reported in both patients and animal models, its functional manifestations and underlying neurophysiological mechanisms in vivo remain unclear. Here, we address this gap using in vivo high-resolution patch-clamp, high-throughput single-unit, and local field recordings in young amyloidopathy mice, at a stage when A{beta} remains largely soluble. We uncover previously unidentified cellular mechanisms in vivo, characterised by reduced inhibitory synaptic input, hypoactivity of fast-spiking interneurons, and enhanced bursting in pyramidal neurons. At the network level, we reveal accelerated hippocampal oscillations, marked by increased theta and beta power, a departure from the conventional view of oscillation slowing in AD. Mechanistically, this acceleration stems from strengthened synchrony of excitatory currents at higher frequencies and an overall reduction in oscillation-associated inhibitory currents. Our findings provide the first direct in vivo evidence linking early hippocampal hyperactivity to specific synaptic transmission and network dysfunctions, resolving a long-standing ambiguity. Moreover, we propose accelerated oscillations in the hippocampus as a functional biomarker for early AD and a potential therapeutic target for restoring network stability before cognitive decline occurs.

Impaired perception of isoluminant contrast modulation stimuli: Evidence for a magnocellular pathway mechanism
Contrast modulation (CM) stimuli have been previously used to reveal nonlinear contributions of Y-like retinal ganglion cells (RGCs) such as parasol cells to cortical responses and perception. To test whether CMs are selectively processed within the magnocellular pathway, we assessed envelope motion discrimination and detection for achromatic (yellow-black) and chromatic (red-green) CMs in the presence of luminance masking noise to disrupt luminance-based mechanisms of motion processing. Compared to achromatic CMs, perception of chromatic CMs was more sensitive to luminance masking noise, suggesting that CM envelope motion perception relied predominantly on luminance signals. Specifically, envelope motion discrimination performance was better maintained for achromatic CMs than chromatic CMs, even at high masking noise levels. Notably, luminance masking noise greatly impaired envelope direction discrimination for chromatic CMs but had minimal impact on their detection, suggesting that chromatic aberrations may enhance envelope motion perception for chromatic CMs by introducing luminance signals. These findings collectively emphasize that CM stimuli selectively activate Y-like/parasol RGCs of the retino-geniculate magnocellular pathway, underscoring their potential to specifically target this pathway. This might have clinical advantages for early diagnosis in disorders such as glaucoma or dyslexia, where magnocellular pathway dysfunction is predominant.

Neurally-informed modelling unravels a single evidence accumulation process for choices and subsequent confidence reports
Subjective confidence in perceptual choices depends on computations occurring prior to and after choice commitment. However, the nature of these computations remains unclear. Current models disagree on two fundamental questions: what stopping-rule is applied to post-choice evidence sampling and to what degree do choice and confidence reports rely on shared versus distinct evidence accumulation processes? These models have proven difficult to dissociate because they often make similar behavioural predictions. Therefore, we used a neurally-informed modelling approach to jointly model initial choices and subsequent confidence reports while leveraging the additional constraints offered by human electrophysiological signatures of evidence accumulation. Participants made self-paced confidence reports after indicating perceptual choices on a random dot motion task, with stimulus presentation continuing during the interval between these responses. Model comparison showed that boundary-based stopping rules provided superior fits to the behavioural data than time-based stopping rules, as the latter could not account for relationships between confidence and confidence-RT. The behavioural fits were inconclusive when comparing models with a single evidence accumulation process dictating choices and confidence reports compared to models invoking a distinct post-choice process. However, the single-process model markedly outperformed the other models in terms of its ability to recapitulate the observed neural evidence accumulation patterns associated with choice confidence. Our study thus demonstrates that choice behaviour, subjective confidence, and associated neural decision signals can be jointly explained by a model invoking a single process of evidence accumulation with separate boundaries for the initial choice and subsequent confidence reports.

An amygdalopontine pathway promotes motor programs of ingestion
Despite internal cues that signal fullness, animals can continue eating when motivated by context or palatability. The neural pathways and signals that enable animals to override these fullness cues remain unclear. We examined a central amygdala (CeA) projection to the dorsolateral pons that targets the parabrachial nucleus, a well-established meal termination center, and the adjacent supratrigeminal nucleus, a region that controls orofacial movements. Activity in this CeApons pathway correlated with licking behavior but was not modulated by metabolic need or palatability cues. CeApons stimulation caused animals to overeat, consume non-edible objects within reach, or exhibit ingestion-like behaviors (licking, chewing, and grasping) even when no target was present. Depending on training and context, stimulation elicited either licking or pellet consumption, suggesting that CeApons promotes a flexible, goal-directed ingestive state by recruiting consummatory motor circuits rather than simply suppressing satiety signals. These findings highlight how forebrain-brainstem interactions can re-engage feeding behavior beyond homeostatic need.

Macrophages amplify the spontaneous activity of damaged sensory neurons in a human co-culture model of neuropathic pain
Neuropathic pain is a highly prevalent condition for which treatments are hampered by low efficacy and dose-limiting side-effects. Injury to the somatosensory nervous system causes maladaptive plasticity that initiates and maintains chronic pain. Emerging evidence suggests that inflammatory cells of the innate immune system shape the response of the injured nervous system and drive pain pathogenesis. Data from preclinical models and human patient biopsies have specifically implicated peripheral macrophage populations for a pro-algesic role, yet how these cell types influence damaged sensory neurons and whether they directly contribute to neuronal hyperexcitability is unclear. Here, we have developed an iPSC co-culture system to study the interactions of macrophages and sensory neurons in a fully humanised experimental model. We found that analogous to endogenous counterparts, iPSC-derived macrophages (iMacs) display a dynamic molecular and functional profile that is highly dependent on neuronal state. Co-culture with injured iPSC-derived sensory neurons (iSNs) induces morphological, gene expression, and secretory profile changes in iMacs that are consistent with findings from in vivo nerve injury studies. iMacs in turn amplify spontaneous firing in damaged sensory neurons, implicating macrophages in this cardinal feature of neuropathic pain. These results illustrate the utility of an iPSC-based model to study signalling between these two cell types; they support a role for macrophages in directly amplifying damaged sensory neuron activity and highlight disrupting pathological signalling between these cell types as a promising strategy for future analgesic drug development.

Exposure to the organochlorine pesticide cis-chlordane induces ALS-like mitochondrial perturbations in stem cell-derived motor neurons
Amyotrophic Lateral Sclerosis (ALS) is a debilitating and incurable neurodegenerative disease with unsolved etiology. Due to the large proportion of patients lacking direct disease inheritance, understanding the environmental factors that contribute to ALS development is of high priority. Epidemiological studies have implicated pesticides and other environmental exposures as possible contributors to ALS pathogenesis. Recently, our group determined that the organochlorine pesticide cis-chlordane is toxic to human motor neurons in a dose-dependent manner, causing an ALS-like phenotype in culture and animals with a mode of action independent of its known GABAA antagonism. Here, we aimed to characterize downstream motor neuron phenotypes associated with cis-chlordane treatment. We performed bulk RNA sequencing, live imaging, immuno-fluorescent labeling, and real-time metabolic assays on stem cell-derived motor neurons to assess chlordane-associated phenotypes in vitro. We demonstrate that cis-chlordane treatment causes a highly altered mitochondrial phenotype in motor neurons, including increased production of reactive oxygen species, decreased OCR and ATP production, and loss of mitochondrial membrane potential. We further implicate cis-chlordane as a possible mediator of potent motor neuron damage, with exposure to the pesticide inducing mitochondrial phenotypes akin to those seen in ALS. We suggest that future studies investigating the role of pesticides in ALS development center upon the organochlorine molecules.

Non-obese genetic type 2 diabetes causes brain and behavioral hallmarks of chronic stress
The comorbidity of obesity, type 2 diabetes (T2D), and psychiatric disorders, particularly anxiety and depression,is well documented. However, it remains unclear whether T2D, independently of obesity, contributes to the development of emotional dysfunctions. Furthermore, alterations in the hypothalamic-pituitary-adrenal (HPA) stress axis are commonly associated with both T2D and depression, but the role of stress in emotional disorders linked to T2D has been poorly explored. This study aimed to investigate the impact of T2D, independent of obesity, on the neuroendocrine stress axis, as well as molecular, cellular, and behavioral indicators of emotional dysfunction. Using the non-obese Goto-Kakizaki (GK) rat model of T2D, we assessed the effects of diabetes on hormonal and neuronal stress responses, molecular and structural markers of stress in the brain, and anxiety- and depressive-like behaviors. We also evaluated the impact of adrenalectomy in GK rats to determine the contribution of glucocorticoids to their behavioral impairments. Our findings reveal that non-obese diabetes leads to heightened endocrine and brain responses to stress, along with upregulation of stress-related molecular markers and structural features indicative of chronic stress, particularly in the medial prefrontal cortex. Additionally, GK rats exhibited pronounced anxiety- and depressive-like behaviors. Importantly, lowering glucocorticoid levels in GK rats helped alleviate some of the metabolic and emotional disturbances. This study suggests that T2D, independent of obesity, induces stress-related brain and behavioral changes, partly mediated by glucocorticoids.

Genomic structural equation modeling of impulsivity and risk-taking traits reveals three latent factors distinctly associated with brain structure and development
Impulsivity is a multifaceted trait that emerges in childhood and is linked to several psychiatric disorders, such as attention-deficit/hyperactivity disorder and substance use disorders. Recent genomic and neuroimaging studies have identified genetic loci and brain systems associated with impulsivity and risk-taking behaviors. However, how these genetic underpinnings overlap across different facets of impulsivity and risk-taking, and how they are associated with brain morphology during early development remain unknown. We applied genomic structural equation modeling to 17 impulsivity and risk-taking GWAS datasets to explore the overlapping genetic architecture underlying these phenotypes. We then computed polygenic scores (PGSs) for each genetic latent factor in 4,142 participants from the Adolescent Brain Cognitive Development Study and examined how each factor was associated with the brain structure during early development. We further tested whether socioeconomic status modulated the association between the PGSs and brain structures. We identified three genetic latent factors, which we labeled as lack of self-control, reward drive, and sensation seeking. These showed distinct associations with brain structure in late childhood and early adolescence, relating to the frontal cortex, subcortical cellularity, and white matter structure in different ways. The association between PGS of lack of self-control and white matter mean diffusivity was modulated by socioeconomic status. Our findings revealed that genetic predisposition for impulsivity and risk-taking is associated with morphological brain differences as early as ages 9--10. We also highlighted the importance of capturing the multidimensional nature of these traits to better understand their neurodevelopmental basis.

Adolescent alcohol consumption alters sex-specific behaviors associated with prefrontal functional connectivity in mice
The prefrontal cortex (PFC) is one of the last brain regions to fully mature, making it particularly sensitive to stress and drug use early in life. Both human and rodent studies find long-lasting behavioral changes after adolescent alcohol exposure that implicate underlying disruptions in PFC development, including structural abnormalities and altered brain functional connectivity. Few rodent studies have been conducted to understand the network-level implications of these disruptions. We assessed how adolescent binge-like alcohol consumption in a drinking in the dark (DID) model affected adult aversion-resistant alcohol consumption, exploration, and brain-wide functional connectivity in mice. Approximately one month after the conclusion of DID, only female mice exposed to alcohol during adolescence exhibited aversion-resistant alcohol preference in adulthood. Adult females exhibited additional sex-specific changes in exploratory behavior in the elevated plus maze after adolescent alcohol consumption. Resting state neuroimaging revealed changes in prefrontal cortical connections with sensory motor, hippocampal, striatal, and other networks, providing insights into the putative systems underlying deficits caused by adolescent alcohol exposure. Critically, our data corroborate a growing body of literature in human and rodent studies demonstrating that adolescent alcohol use may increase risk for adulthood alcohol use more strongly in females. Finally, we identify neural correlates of this effect that include both known and novel networks and tie these back to human datasets, allowing biological and mechanistic targets to be further explored for future study and interventions.

Drosophila larval Odd neurons process innate and learned information to regulate chemotaxis behavior
Adaptive decision-making emerges from the integration of innate preferences and learned experiences to guide behavior. Using Drosophila larvae as a model, we investigated the neural circuitry underlying olfactory processing, focusing on Odd neurons-a distinct neuronal population that receives innate valence signals from Kenyon cells (KCs) rather than lateral horn inputs. Through larval connectomics, trans-tango labeling, and detailed anatomical analyses, we found that Odd neurons integrate innate valence through dendro-dendritic connections with KCs and learned valence via inhibitory inputs from mushroom body output neurons (MBON-g1 and MBON-g2). Optogenetic silencing of Odd neurons disrupted larval chemotaxis and associative memory by selectively impairing memory retrieval, while sparing memory formation, and by altering the turn rate during navigation. These results suggest that Odd neurons serve as an integrative hub, converging innate olfactory cues with learned reinforcement signals to fine-tune navigational choices. This study illuminates how distinct neural pathways converge in the larval brain to shape behavior, offering novel insights into decision-making circuitry that may extend to more complex nervous systems.

Constant light impairs memory processing transgenerationally in D. melanogaster
Environmental perturbations can have profound effects on our physiology and behavior, but their long-lasting impact remains debatable. We discovered that changes in standard light-dark conditions, such as exposure to constant light or simulated chronic jetlag, causes loss of associative memory in appetitive and aversive conditioning paradigms in D. melanogaster, and this behavior persists through three generations despite transfer of progeny to a standard light-dark cycle. Impaired memory is transmitted through females and is independent of any changes in fitness, brain or mushroom body architecture, or sensing acuity. Mechanistically, effects of constant light on memory are mediated by increased PIWI/piRNA pathway expression in the germline and its H3K9me3 writing capabilities, acting through altered expression of the Dopamine-1-like Receptor 1 (Dop1R1) in the brain. These findings suggest that irregular exposure to light, such as nighttime light pollution, can have negative consequences across generations.

A Tiered Approach to Human Synapse Proteomics: Optimized LC-MS/MS Analysis of Whole-Tissue and Synaptosome Preparations from Frozen Post-mortem Brain Samples
Recent advancements in neuroproteomics have enabled detailed analysis of protein expression and function in the human brain. Post-mortem human brain studies have significantly advanced our understanding of the relationship between genetics, cell biology of neurological and psychiatric disorders and their clinical diagnosis and their clinical diagnosis. Given the central role of the synapse in these disorders, we evaluated the sensitivity of liquid chromatography-tandem mass spectrometry (LC-MS/MS) to detect synaptic proteins in whole-cell lysates versus synaptosome preparations. First, we optimized sample preparation protocols for frozen human gray matter (GM), refining the suspension TRAPping (S-TRAP) digestion method to improve protein solubilization using thin tissue sections and to accomplish low technical variation by minimizing sample handling. Together, we achieved a highly reproducible sample preparation workflow by rigorously applying standardization and randomization across dissection, processing, and LC-MS/MS runs. Comparative LC-MS/MS analysis showed that whole-tissue lysates are practical for large-scale studies and broadly detecting synaptic proteins. However, enrichment by synaptosome isolation offered improved resolution of synapse-specific proteins. Because synapse-proteomics enables insight into spatial regulation -i.e., alterations at the synapse that are not reflected in the soma- we recommend a tiered approach: initial whole-tissue analysis for broad disease-associated changes, followed by targeted synaptosome proteomics to deepen insight into synaptic alterations. This strategy optimally balances throughput, reproducibility, and biological relevance, and enhances the study of brain disorders through proteomics. Moreover, analyzing synaptic proteins first at the tissue level improves insight into overall regulation of synaptic proteins induced by synapse loss or gain.

Sex-specific Effects of Outdoor Air Pollution on Subcortical Microstructure and Weight Gain: Findings from the ABCD Study
Obesity is associated with structural alterations of brain regions that support eating behavior. Exposure to air pollutants might exacerbate this association through neurotoxic effects on the brain. This study evaluated whether air pollution exposure 9-10 years old children, coupled with brain microstructure development in appetite-regulating regions, is associated with body mass index (BMI) changes over two years, and whether these associations differ by sex. Data were gathered from the Adolescent Brain Cognitive Development Study (nbaseline=4,802, ages=9-10, males=49.9%, nfollow-up=2,439, ages=11-12, males=51.1%). Annual average estimates of ambient fine particulate matter (PM2.5), nitrogen dioxide (NO2), ground-level ozone (O3), and redox-weighted oxidative capacity (Oxwt, a joint measure of NO2 and O3) were gathered from youth's residential addresses. Brain microstructure in 16 subcortical regions was assessed using diffusion-weighted MRI, focusing on proxies of cellular and neurite density: restricted normalized isotropic (RNI) and directional (RND) diffusion, respectively. Linear mixed-effects models examined whether air pollution and brain microstructure are related to BMI changes over two years, and whether these associations differed by sex. Exposure to PM2.5 coupled with high RND estimates in right caudate nucleus, bilateral putamen, and pallidum were associated with higher BMI over time, with pronounced effects in males (all p<0.05). PM2.5 coupled with greater neurite density in regions involved in reward-processing and decision-making were associated with higher BMI over a 2-year follow-up, especially in males. This research highlights air pollution as a modifiable risk factor for how differences in basal ganglia neurite density map onto obesity risk, with important implications for public health policy.

The Role of Paraventricular Nucleus of Thalamus in Sleep Disturbance Induced by Withdrawal from Repeated Ethanol Exposure
Sleep disturbance is known to be comorbid with withdrawal from repeated ethanol exposure and could be a negative reinforcement for the majority of people with alcohol use disorder (AUD). The paraventricular nucleus of the thalamus (PVT) has been highlighted for its function in integrating arousal states and associated modulation in sleep homeostasis. However, there is limited understanding of the involvement of PVT neurons in regulating sleep patterns, especially during withdrawal from chronic ethanol exposure. In this study, we investigated the potential function of the PVT in sleep disturbance during ethanol withdrawal using electrophysiology, in vivo calcium imaging, biochemical, and chemogenetic approaches. At 24 hours post-withdrawal from chronic intermittent ethanol exposure (CIE) for four weeks, there is an increase in wake time and a decrease in non-rapid eye movement (NREM) sleep. The calcium transient levels in the PVT neurons are positively correlated with the transition from sleep to wakefulness. CIE elevates the PVT neuronal activity in a subregion-specific manner, resulting in a significant rise in cFos levels in the anterior PVT (aPVT). Temporal suppression of aPVT excitatory neurons via chemogenetics ameliorates the disturbance in sleep patterns generated by CIE. The aPVT has a notable distinction in the expression of the m-type potassium channel subunit, KCNQ2, with a higher expression level compared to the posterior PVT (pPVT). While the expression of KCNQ2 in the aPVT is reduced in CIE mice, the restoration of KCNQ2 expression using viral gene transfer within the aPVT alleviates the sleep disturbances produced by CIE. This data indicates a significant role of the PVT in sleep disturbance during ethanol withdrawal, which may partially be due to the downregulation of M-channels, hence underscoring M-channels in the PVT as a potential therapeutic target for sleep disturbance in alcohol use disorder.

Disrupted Forward Connectivity in Parieto-temporal Network Impairs Memory Performance in Alzheimer's Disease
Alzheimer's disease is characterised by the accumulation of beta-amyloid (A{beta}) and tau proteins, leading to neurodegeneration and cognitive decline. While A{beta} and tau are known to disrupt synaptic function, the mechanisms linking these molecular pathologies to network-level dysfunction and memory impairment remain poorly understood. Here we investigated the effects of A{beta} and tau pathology (CSF A{beta}42/40 ratio and tau phosphorylated at position 181, p-tau-181, respectively) on effective connectivity (EC) related to memory encoding, which may constitute a link between synaptic pathology and cognitive outcomes. Functional magnetic resonance imaging (fMRI) during visual memory encoding was acquired from participants of the multicentric DZNE Longitudinal Cognitive Impairment and Dementia Study (DELCODE), including 203 cognitively normal older participants (CN) as well as individuals with subjective cognitive decline (SCD; N = 204), mild cognitive impairment (MCI; N = 65), and early dementia due to AD (DAT; N = 21). EC was assessed by applying Dynamic causal modelling (DCM) to the fMRI data, using brain regions previously implicated in memory-encoding: the parahippocampal place area (PPA), the hippocampus (HC) and the precuneus (PCU). Disruptions in forward connectivity from the PPA to the HC and PCU were associated with both memory impairment and indices of AD pathology. Specifically, reduced excitatory EC from the PPA to the HC was associated with higher p-tau-181 levels and correlated with poorer memory performance. Diminished inhibitory EC from the PPA to the PCU was driven by both tau and amyloid pathology and was likewise linked to memory decline. Our findings suggest that disrupted forward connectivity within the temporo-parietal memory network constitutes a candidate mechanism mediating the relationship between molecular pathology and cognitive dysfunction.

Nociceptin/Orphanin FQ receptor agonism attenuates behavioral and neural responses to conditioned aversive stimuli
The nociceptin/orphanin FQ peptide (NOP) receptor has emerged as a promising anxiolytic target, as its activation has been shown to reduce anxiety-related behaviors in rodents. However, the mechanisms underlying these effects are not well understood. Here, we investigated the effects of the selective NOP receptor agonist SCH-221510 (SCH; 0.01-0.1 mg/kg, IM) on behavioral and neural responses to aversive stimuli in squirrel monkeys (n=3). Subjects underwent Pavlovian fear conditioning, wherein a visual conditioned stimulus (CS) was paired with the presentation of an aversive stimulus. Event-related fMRI was conducted in awake subjects to evaluate CS-evoked neural responses. Behavioral and neural responses to the CS were assessed across three experimental phases: pre-conditioning (Pre-C), post-conditioning (Post-C), and Post-C with SCH administration. In behavioral assessments, CS presentation during Post-C elicited a robust suppression of ongoing operant responding, which was absent during Pre-C and significantly attenuated by SCH treatment (0.1 mg/kg). Functional magnetic resonance imaging (fMRI) results revealed that, relative to Pre-C, CS presentation during Post-C was associated with increased BOLD activity in brain regions previously implicated in fear processing (e.g., amygdala), expression and regulation (e.g., prefrontal cortex; PFC), as well as sensory integration. Critically, SCH (0.1 mg/kg) administration significantly attenuated CS-induced neural activation in these regions. Furthermore, resting-state functional connectivity analysis revealed that SCH administration decreased connectivity between the PFC and the amygdala, while enhancing connectivity among subregions of the PFC. Collectively, these findings suggest that NOP receptor agonism may attenuate conditioned responses to aversive stimuli by modulating functional interactions within the PFC-amygdala circuit.

Functional Brain Imaging and Targeted Lesion Studies Using Manganese-Enhanced MRI and Focused Ultrasound in Non-Conventional ModelSpecies
Linking behavior to its neuroanatomical basis in non-conventional model species remains a significant challenge due to the scarcity of imaging and molecular tools. Commonly used approaches such as electrophysiological recordings rely on precise stereotaxic atlases or species-specific antibodies, while optogenetics requires transgenic lines which are largely unavailable beyond classical model organisms (e.g., mice, rats, zebrafish). Moreover, surgical lesion studies, a staple for verifying brain structure and behavior relationships, are logistically complex in species lacking atlases or living in aquatic environments. Here, we present a protocol integrating Manganese-Enhanced Magnetic Resonance Imaging (MEMRI) and MR-guided High-Intensity Focused Ultrasound (HIFU) to overcome these limitations, which we demonstrate in the convict cichlid (Amatitlania nigrofasciata), a teleost fish lacking conventional neuroscience tools. MEMRI enables non-invasive, sub-millimeter resolution mapping of brain activity during behavior, and HIFU facilitates precise, surgery-free lesioning of targeted regions, adaptable to species without stereotaxic atlases. This combined approach offers a versatile, broadly applicable framework for linking brain structure and behavior in non-model organisms, advancing evolutionary and comparative neuroscience.

Astrocytic CREB regulates transcriptional, neuronal, and behavioral responses to cocaine
Drug addiction is characterized by neuronal adaptations that support a shift from goal-directed behaviors to habitual, compulsive drug-seeking with persistent effects on cognition and decision-making. Emerging evidence increasingly indicates that astrocytes are also involved in nervous system disorders, including addiction, but the cocaine-induced astrocyte-specific transcriptome has not yet been investigated. We utilized whole cell sorting of astrocytes, RNA-sequencing, and bioinformatic approaches to characterize the astrocyte transcriptome in the nucleus accumbens (NAc), a key brain region involved in reward-processing, following cocaine self-administration, prolonged abstinence, and relapse in male mice. We found that astrocytes exhibit robust and contextually-specific transcriptional signatures that converge strongly with human cocaine use disorder. Bioinformatic analysis revealed CREB as a highly ranked predicted upstream regulator of cocaine-induced transcriptional regulation in NAc astrocytes, and CUT&RUN-sequencing mapped increased CREB binding across the astrocyte genome in response to cocaine. Viral-mediated manipulation of CREB activity selectively in NAc astrocytes, in combination with several measures of addiction-related behaviors including conditioned place preference and self-administration, revealed that astrocytic CREB increases the rewarding and reinforcing properties of cocaine. This effect is sex-specific, with no change in astrocytic CREB activity or CPP found in females. Subsequent experiments identify potential molecular mechanisms of astrocytic CREB influence through modulating astrocytic Ca2+ signaling in response to cocaine. Finally, we show that astrocytic CREB selectively modulates D1-type medium spiny neurons in NAc to control cocaine-related behaviors. Together, these data demonstrate that the astrocyte transcriptome responds robustly to cocaine and that CREB mediates the effects of cocaine on gene expression in astrocytes, with consequent effects on neuronal activity and rewarding responses to the drug.

Spatial coupling of endogenous Tau translation and degradation by neuroproteasomes in dendrites revealed by STARFISH
Cells regulate protein synthesis, folding, and degradation to maintain proteostasis, and disruptions in these processes have been linked to neurodegenerative diseases. In Alzheimers disease (AD), the protein Tau mislocalizes from axons to the somatodendritic compartment and aggregates into pathological filaments. Although Tau aggregation is a hallmark of AD, the subcellular dynamics of its synthesis and degradation are not well characterized. Because nascent polypeptides are particularly susceptible to misfolding, local control of Tau synthesis and degradation may be essential to prevent aggregation. Here, we develop STARFISH, a method for visualizing the subcellular site of endogenous mRNA translation in primary neurons and in vivo with single-molecule sensitivity and near-codon resolution, without modifying the nascent polypeptide. Using STARFISH, we show that despite the broad distribution of Mapt mRNA, Tau is translated almost exclusively in neuronal dendrites, revealing an unexpected level of spatial regulation. We further identify that one-third of newly synthesized Tau is co- or peri-translationally degraded in dendrites by a neuronal-specific plasma membrane-associated proteasome, the neuroproteasome. Failure of neuroproteasome-mediated degradation leads to the protein synthesis-dependent accumulation of somatodendritically mislocalized Tau aggregates. These findings define a previously unrecognized proteostasis mechanism that counterbalances the constitutive physiological overproduction of Tau. We speculate that failure of this proteostasis system contributes directly to Tau aggregation in dendrites, defining a new pathomechanism in Alzheimers disease.

Comparing electromyography, accelerometry, and visual inspection to assess the resting motor threshold for transcranial magnetic stimulation
Introduction: Electromyography (EMG) remains the gold standard for estimating the Resting Motor Threshold (RMT) Transcranial Magnetic Stimulation (TMS) studies, but its cost and limited accessibility often lead researchers to use visual inspection (VIS). However, VIS may introduce variability and systematic bias. Accelerometry (ACC) offers a cost-effective, objective alternative to capture TMS-evoked responses. Objective: To compare the RMT as estimated using EMG, ACC, and VIS. Methods: Five participants underwent TMS while EMG, ACC, and video recordings were collected. Separately, 64 observers judged hand movement in videos to estimate RMT via VIS. RMTs were compared across the three methods using Bayesian model comparison, Bland-Altman analyses, and Intraclass Correlation Coefficients (ICCs). Results: RMTs estimated via EMG were lower than those obtained using either ACC or VIS. Compared to EMG, VIS tended to overestimate RMT (mean bias = 5.23%, 95%CI = [1.00-11.00]), while ACC and VIS estimates were more closely aligned (mean bias = 0.43%, 95%CI = [-4.00 - 5.00]). ICC (2,1) values indicated moderate reliability for VIS vs EMG (mean = 0.580, 95%CI = [0.389 - 0.748]), and good-to-excellent reliability for VIS vs ACC (mean = 0.845). However, bootstrapped 95% confidence intervals identified significant variability in the estimates provided by visual inspection, ranging from +1 to +11 for VIS vs EMG, but as low as -4 to +5 for VIS vs ACC. Conclusions: EMG remains the most sensitive technique for estimating the RMT, but when EMG is not feasible, accelerometery provides a quantifiable, more objective, and less variable alternative than visual inspection.

From Few Labels to Full Insight: 3D Semantic Segmentation of Brain White Matter Microstructures from a Sparsely Annotated X-ray Nano Holotomography Dataset
Morphological analysis of white matter (WM) microstructures provides invaluable insights into its function and brain health overall. Recently, synchrotron X-ray Nano Holotomography (XNH) imaging has gained momentum in microstructural studies owing to its unique combination of capabilities, including a wide field of view (FOV), nanoscale resolution, and fast volumetric acquisition. However, the 3D segmentation of tiny and densely packed microstructures within the WM, the very first step toward quantification, presents a significant bottleneck. Herein, we address this challenge using an expert-in-the-loop 3D deep learning (DL) framework. The initial model was a 3D U-Net architecture trained on sparsely annotated data, exclusively from the corpus callosum (CC), a region characterized by relatively simple axonal morphology and parallel orientation of axonal bundles. The high-confidence predictions (p > 0.7) from both CC and complex crossing fiber regions are then refined by an expert and reintegrated into the training process to expand the training dataset and corresponding labels. Building upon this foundation, we benchmarked alternative architectures, including 3D convolutional neural networks (CNN) and transformer-based architectures, alongside different loss functions. We showcased the segmentation performance of the models on XNH volumes with varying microstructural morphology and organization complexities. All DL architectures achieved satisfactory performance with overall segmentation accuracy > 0.96 and an average Dice score > 0.8 in 3D segmentation of axons, blood vessels, cells, and vacuoles. This study presents a multi-class 3D segmentation of WM microstructures in large FOVs up to 202 x 202 x 780 m3 scanned through XNH technology. Our framework not only accelerates high-fidelity segmentation in challenging datasets but also paves the way for fast quantitative analysis in large-scale 3D neuroimaging studies.

The Pathological Role and Therapeutic potential of ALDH2 in acrolein detoxification Following Spinal Cord Injury in Mice
Oxidative stress and lipid peroxidation-derived aldehydes, such as acrolein, play a central role in the pathology of spinal cord injury (SCI) and have emerged as promising therapeutic targets. Mitochondrial aldehyde dehydrogenase-2 (ALDH2) is a key oxidoreductase responsible for detoxifying reactive aldehydes. Pharmacological activation of ALDH2 using Alda-1, a selective agonist, has been shown to reduce aldehyde accumulation, alleviate inflammation, and enhance functional recovery in experimental SCI models. However, approximately 8% of the global population carries the ALDH2*2 mutation, which severely impairs this detoxification pathway. In this study, we used a transgenic ALDH2*2 mouse model to investigate the role of ALDH2 in SCI pathology. This model mimics the human ALDH2*2 condition, allowing us to examine the impact of impaired aldehyde clearance on acrolein accumulation and its pathological consequences. We modulated endogenous aldehyde detoxification through both genetic deficiency and pharmacological activation with Alda-1. Our results showed that ALDH2 deficiency led to significantly elevated acrolein levels, which were associated with increased microglial activation, cytokine storm, neuronal loss, demyelination, and tissue damage compared to wild-type (WT) mice. Treatment with Alda-1 enhanced ALDH2 activity and significantly reduced acrolein levels in both ALDH2*2 and WT mice from 2 to 28 days post-SCI. This was accompanied by reduced inflammation, improved preservation of myelin, and marked improvements in locomotor and sensory function, especially in ALDH2*2 mice. Notably, even beyond the traditionally ideal treatment window, Alda-1 treatment remained effective in promoting recovery, particularly in motor function and to a greater extent in ALDH2*2 mice. Our study comprehensively evaluated ALDH2's role in SCI by both genetically impairing and pharmacologically enhancing its activity, highlighting ALDH2 as a critical modulator of acrolein-mediated damage and suggesting its potential as a therapeutic target, especially for individuals with the ALDH2*2 mutation.

It takes experience to tango: Experienced cochlear implantusers show cortical evoked potentials to naturalistic music
Approximately 30% of cochlear implant (CI) users report that restoring their ability to enjoy music is a primary goal. However, music perception in CI users has mostly been investigated in controlled laboratory settings using simplified stimuli, such as pure tones or monophonic melodies. There is an increasing interest in developing objective measures of CI outcomes in everyday listening situations, particularly in music listening, which involves complex stimuli rich in timbre, pitch, rhythm, and overlapping sounds. One promising approach is to measure cortical auditory evoked responses (ERs) in CI users. We investigated whether ERs to sound onsets in a naturalistic four-minute music piece could be measured in adult CI users (N: 25; ages 18-80; CI experience: 0.3-14 years). We assumed that the accumulation of CI experience might be reflected in the morphology of the ERs. The results confirmed that P2 responses to sound onsets embedded in a whole piece of music can be detected in experienced CI users. Compared to a control group with normal hearing, the CI users showed P2 responses with lower amplitudes and longer latencies. Exploratory linear regression models suggested that the logarithmic duration of CI experience significantly predicted both perceived quality of musical sounds and P2 amplitude, explaining 38% and 28% of the variance, respectively. The findings suggest that music perception outcomes may continue to improve for up to 2-4 years post-implantation. Altogether, the results are consistent with the use of ERs to track CI adaptation to music listening.

Magnetoelectric nanodiscs diminish motor deficits in a model of Parkinson's disease
Deep brain stimulation (DBS) with electrodes implanted in the subthalamic nucleus (STN) alleviates motor symptoms in Parkinson's disease (PD). However, the surgical complexity and associated side effects limit deployment of DBS to late-stage patients. Here, we explore a neuromodulation approach that employs locally injected magnetoelectric nanodiscs (MENDs) as an alternative to electrode-based DBS. The MENDs, composed of Fe3O4 cores and two consecutive shells of magnetostrictive CoFe2O4 and piezoelectric BaTiO3, convert weak magnetic fields into electric polarization, enabling remote neuronal excitation in the mouse STN comparable to electrode DBS. To assess the effects of the MEND and electrode DBS on motor performance in a unilateral mouse model of PD, we develop a computational pipeline that extracts salient gate features. Our findings suggest that DBS mediated by the injected MENDs not only diminishes motor symptoms associated with PD but may also inform future strategies for early-stage interventions aimed at delaying disease progression.

Nociceptin receptor and ligand in Alzheimer's disease:Implications for psychiatric symptoms and circadianregulation
Background: Nociceptin (N/OFQ) and its receptor OPRL1 play crucial roles in emotional processing, reward-related behaviors, learning, and neurotransmitter regulation, but their involvement in Alzheimer's disease (AD) pathology remains poorly understood. This study investigated possible relationships between prepronociceptin (PNOC) and OPRL1 expression and psychiatric symptoms in AD, utilizing Natural Language Processing (NLP) to assess Research Domain Criteria (RDoC) domains. Methods: Post-mortem brain tissue from the dorsal anterior cingulate gyrus (BA32) was analyzed in 61 donors across different Braak and Braak (B&B) stages. RNA expression of PNOC and OPRL1 was quantified and correlated with RDoC scores derived from medical records using NLP. Sex-stratified analyses, circadian rhythmicity analysis, and cell-type specific expression patterns were examined. Results: Both genes showed significant downregulation in AD cases (PNOC: p = 0.024; OPRL1: p < 0.001), with notable sex differences. Men displayed higher post-mortem PNOC (Cohen's d = -0.482) and OPRL1 (Cohen's d = -0.237) expression compared to women. In adjusted models controlling for B&B stage and post-mortem interval, PNOC expression significantly correlated with dimensional scores of positive valence ({beta} = -0.38, p = 0.035) and arousal regulatory systems ({beta} = -0.43, p = 0.015) derived from a text classification algorithm applied to medical records. OPRL1 showed disrupted circadian rhythmicity in AD cases (p = 0.151 vs. p = 0.020 in controls). Conclusions: These findings suggest distinct roles for PNOC and OPRL1 in AD pathology, with PNOC primarily associated with psychiatric symptoms and OPRL1 showing disrupted circadian regulation. Sex-specific expression patterns further indicate the need for personalized therapeutic approaches targeting the nociceptin system.

Riding the savory horse: An active mindset and food macronutrient composition influence attentional bias toward food cues
Food cues that appear in the visual field capture our attention easily and can influence eating behavior. The current study investigated the influence of food-related stimuli on visual attention, considering the macronutrient composition of food items. Images representing sweet and savory foods were employed, the latter consisting primarily of high-protein foods. The participants were primed with these images prior to performing the attentional task. We found that both sets of food images elicited an emotional attentional blink (EAB), but a stronger EAB was observed for the high-protein foods, and this observation was further supported by a negative correlation between the attentional bias (ABias) and the proportion of protein consumed by the participants before the experiment, with participants who consumed less protein exhibiting a stronger ABias toward high-protein foods. These findings suggest that an ABias might also arise to facilitate the consumption of high-protein foods when prior consumption of this macronutrient is low.

Infection-Specific Reprogramming of Microglia Reveals Distinct Virulence Pathways Linking Periodontal Pathogens to Alzheimer's Disease
Microglial dysregulation is increasingly recognized as a driver of Alzheimer's disease (AD), yet how pathogen-specific cues sculpt microglial diversity remains unclear. Here we integrate high-dimensional single-cell cytometry in vitro with spatial proteomics in vivo to dissect the impact of two major periodontal pathogens on microglia. Using a 36-marker CyTOF panel, we exposed SIM A9 microglia to wild-type Porphyromonas gingivalis (Pg) or Tannerella forsythia (Tf) and to gingipain-deficient or S-layer-deficient mutants, resolving 38 clusters. Virulence-factor "switches" redirected cells from homeostatic states toward i) oxidative, antigen-presenting programmes driven by Pg gingipains and ii) an immunosuppressive, exhausted-like state driven by the Tf S-layer. Complementary 37-marker imaging mass cytometry of 5xFAD x hTau knock-in mice chronically infected with Pg identified 21 microglial subclusters. The cortex - but not hippocampus - lost two Arg1+/IL-10+ immunoregulatory subsets (>2-fold decrease) while NADPH oxidase-high microglia accumulated around amyloid-{beta} and tau aggregates. These data demonstrate pathogen-specific reprogramming of microglia across model systems and brain regions, linking virulence factor activity to AD-relevant neuroinflammation. By pinpointing gingipains and the bacterial S-layer as molecular "switches", our study highlights tractable therapeutic targets for limiting infection-driven microglial dysfunction in Alzheimer's disease.

Modality-Agnostic Decoding of Vision and Language from fMRI
Humans perform tasks involving the manipulation of inputs regardless of how these signals are perceived by the brain, thanks to representations that are agnostic to the stimulus modality. Investigating such modality-agnostic representations requires experimental datasets with multiple modalities of presentation. In this paper, we introduce and analyze SemReps-8K, a new large-scale fMRI dataset of 6 subjects watching both images and short text descriptions of such images, as well as conditions during which the subjects were imagining visual scenes. The multimodal nature of this dataset enables the development of modality-agnostic decoders, trained to predict which stimulus a subject is seeing, irrespective of the modality in which the stimulus is presented. Further, we performed a searchlight analysis revealing that large areas of the brain contain modality-agnostic representations. Such areas are also particularly suitable for decoding visual scenes from the mental imagery condition. The dataset will be made publicly available.

Long-Range Input to Cortical Microcircuits Shapes EEG-BOLD Correlation
Although generated by different mechanisms, electroencephalography (EEG) rhythms and blood-oxygen-level-dependent (BOLD) activity have been shown to be correlated. The level of correlation varies between EEG frequency bands, brain regions and experimental paradigms, but the underpinning mechanisms of this correlation remain poorly understood. Here we create a mathematical, data-informed model of a cortical microcircuit that encompasses all major neuron types across cortical layers, and use it to generate EEG and BOLD under various external input conditions. The model exhibits noise-driven fluctuations mimicking EEG rhythms, with external inputs modulating EEG spectral characteristics. Consistent with experimental results, we observe negative alpha-BOLD correlation and positive gamma-BOLD correlation across different input configurations. Temporal variability of the input is found to increase EEG-BOLD correlation and to improve the correspondence with experimental results. This study provides a mathematical framework to theoretically study the correlation of EEG and BOLD features in a comprehensive way.

Circadian timing and entrainment properties of the SCN pacemaker in the PS19 mouse model of Tau pathology
Tauopathies are a group of neurodegenerative disorders caused by the misfolded microtubule-associated protein tau (MAPT), leading to its abnormal accumulation and hyperphosphorylation, and resulting in neuronal dysfunction and death. Tauopathy patients also experience disruptions to circadian rhythms of behavior and sleep. The connection between tau pathology and circadian dysfunction is not well understood, especially regarding the role of the suprachiasmatic nucleus (SCN), the brain's central circadian pacemaker. Here, we conducted histological and functional analyses of the SCN in the PS19 (Prnp-huMAPT*P301S) mouse model of tauopathy. The SCN of PS19 mice had accumulation of phosphorylated tau as early as 2 months of age, and tau pathology was detected in both major neuronal subpopulations of the SCN: VIPergic (core) and AVPergic (shell) neurons. To assess SCN timing and entrainment properties, daily locomotor activity was monitored in PS19 and wild-type (WT) mice from 3 to 11 months-of-age. Activity profiles, rates of re-entrainment to changes in the light/dark cycle, and intrinsic circadian timing properties were unchanged in PS19 mice compared to age-matched WT mice. Finally, profiling circadian gene expression in tau fibril-seeded SCN explants from PS19 and WT mice did not detect differences in network-level oscillator properties. Together, these findings suggest that tau pathology within the SCN is not sufficient to trigger marked disruptions of core circadian timing mechanisms in this tauopathy model. Further, these results raise the possibility that circadian disruptions in tauopathies arise from dysfunction in SCN-gated output pathways or downstream clock-gated circuits rather than the SCN oscillator itself.

Ultrafast endocytosis in mouse cortical inhibitory synapses
Neural circuitry depends on excitatory and inhibitory regulation of activity to yield functional outputs. However, examinations of synaptic vesicle recycling have focused heavily on excitatory synapses, leaving many questions unanswered for inhibitory synapse dynamics. Here we show that both excitatory and inhibitory cortical synapses contain depots of a protein essential for ultrafast endocytosis, Dynamin 1xA, at a region immediately next to the active zone where ultrafast endocytosis takes place. Using zap-and-freeze time-resolved electron microscopy in mouse acute cortical slices, we observe uncoated pits reminiscent of ultrafast endocytic intermediates appearing post-stimulus at putative inhibitory synapses. These findings suggest that excitatory and inhibitory synapses may perform similar modes of endocytosis.

Differential microstructural development within sensorimotor cortical regions: A diffusion MRI study in preterm and full-term infants
The sensorimotor system develops early in utero and supports the emergence of body representations critical for perception, action, and interaction with environment. While somatotopic protomaps are already developed in the primary somatosensory and motor cortices in late pregnancy, little is known about the anatomical substrates of this functional specialization. In this study, we aimed to decipher the microstructural properties of these regions in the developing brain. Using advanced diffusion MRI and post-processing tools, we parcellated the pre- and post-central gyri into microstructurally distinct clusters along the lateral-to-medial axis in full-term neonates, confirming the early differentiation within sensorimotor regions. These clusters were further analyzed in preterm infants scanned near birth and at term-equivalent age (TEA), compared with another group of full-term neonates. Applying a multivariate Mahalanobis distance approach, we quantified deviations in preterm cortical microstructure relative to the full-term reference. Preterm infants showed significant region- and position-specific deviations at both ages, though these were smaller at TEA, consistently with ongoing maturation during the pre-term period. Differences between the pre- and post-central gyri, and along the somatotopic axis, suggested differential vulnerability to prematurity. In particular, the motor regions appeared to be at a more advanced stage of maturation close to birth and less vulnerable at TEA than somatosensory regions. An opposite trend was observed for lateral positions related to mouth representation compared with intermediary and medial positions. These findings support the notion that early sensorimotor cortical specialization is microstructurally emergent during gestation and sensitive to atypical developmental context of preterm birth.

Whisker stimulation reinforces a resting-state network in the barrel cortex: nested oscillations and avalanches
The cerebral cortex operates in a state of restless activity, even in the absence of external stimuli. Collective neuronal activities, such as neural avalanches and synchronized oscillations, are also found under rest conditions, and these features have been suggested to support sensory processing, brain readiness for rapid responses, and computational efficiency. The rat barrel cortex and thalamus circuit, with its somatotopic organization for processing whisker movements, provides a powerful system to explore such interplay. To characterize these resting state circuits, we perform simultaneous multi-electrode recordings in rats' barrel cortex and thalamus. During spontaneous activity, oscillations with frequencies centered around 11.5 Hz are detected concomitantly with slow oscillations below 4 Hz, as well as power-law distributed avalanches. The phase of the lower-frequency oscillation appears to modulate the higher-frequency amplitude, and it has a role in gating avalanche occurrences. We then record neural activity during controlled whisker movements to confirm that the 11.5 Hz barrel circuit active at rest is indeed the one involved in response to whisker stimulation. We finally show how a thalamic-driven firing-rate model can describe the entire phenomenology observed at resting state and predict the response of the barrel cortex to controlled whisker movement.

A Radiomic Approach to Clinical MRI Refines the Thalamus-Cognition Link in Multiple Sclerosis
Background and Objectives: Radiomics extracts imaging features that may not be detectable through conventional volumetric analyses. Given their role in multiple sclerosis (MS), we applied radiomics to thalamic nuclei and examined their associations with cognitive performance. Methods: A total of 601 individuals were included (342 people with MS-PwMS from two cohorts, and 259 healthy controls-HC). Radiomic features (RF) and volumes were extracted from the whole thalamus, five thalamic nuclei, and the putamen segmented on 3D T1-weighted images. Cognitive performance was assessed using the Symbol Digit Modalities Test (SDMT) and Paced Auditory Serial Addition Test (PASAT) in PwMS, and the Digit Symbol Substitution Test (DSST) in HC. In the first MS cohort, multivariate linear regression in a discovery set (N=103) identified thalamus-derived RF associated with SDMT, which were retested in a replication set (N=63). Their associations with PASAT in a second MS cohort (N=176) and DSST in HC were also evaluated. We then tested whether the same RF, when extracted from the putamen, were associated with SDMT. LASSO models assessed the combined predictive value of RF and volumes. Results: Twenty-eight RF_ROI pairs were associated with SDMT in the replication set (FDR<0.05). Of these, 24 were also associated with PASAT (FDR[≤]0.03), and 2 with DSST Only ventral nuclei volume showed replicated associations among volumetrics. Only 4 putamen-derived pairs were associated with SDMT (FDR=0.04). LASSO results confirmed RF outperformed volumes. Discussion: RF extracted from the thalamus are strongly associated with cognitive performance in PwMS, outperforming volumetric measures and supporting their potential as sensitive imaging biomarkers.

Error encoding in human speech motor cortex
Humans monitor their actions, including detecting errors during speech production. This self-monitoring capability also enables speech neuroprosthesis users to recognize mistakes in decoded output upon receiving visual or auditory feedback. However, it remains unknown whether neural activity related to error detection is present in the speech motor cortex. In this study, we demonstrate the existence of neural error signals in speech motor cortex firing rates during intracortical brain-to-text speech neuroprosthesis use. This activity could be decoded to enable the neuroprosthesis to identify its own errors with up to 86% accuracy. Additionally, we observed distinct neural patterns associated with specific types of mistakes, such as phonemic or semantic differences between the person's intended and displayed words. These findings reveal how feedback errors are represented within the speech motor cortex, and suggest strategies for leveraging these additional cognitive signals to improve neuroprostheses.

Opposing responses of hippocampal theta oscillations to running and a forelimb-dominated sensorimotor behavior
Hippocampal theta oscillations regulate the timing of neurons to support navigation, memory formation, and sensorimotor integration. Theta is modulated by running speed, breathing, whisking, and jumping and increases in tasks involving memory encoding or retrieval. The positive relationship between theta frequency and running speed is believed stabilize hippocampal representations of space amid movement variability. Here, we incorporated a novel string-pulling task to determine if established relationships between movement and theta hold when progress to a reward is determined by the length of string pulled. This task eliminates many speed-associated inputs, such vestibular, visual, and hindlimb information, and allows an unprecedented level of precision in the analysis of individual paw movements. Given that animals move the string a fixed length to acquire a reward, we predicted that the positive relationship between theta frequency and speed would hold. Approach: Five Sprague Dawley rats (4 mo.) were trained to continuously pull a string a fixed distance of 208 cm using an automated string-pulling system and run on a track for food reward. Local-field data was acquired from electrodes in dorsal CA1. Results: Relationships between theta and movement speed were distinct during string pulling and running. While theta was robust in both conditions, frequency was significantly reduced during string-pulling and showed no speed-frequency coupling, unlike running. This difference could result from the conflict between hindlimb and forelimb signals, with only forelimb movement signaling advancement. Fine-grained analysis of paw movements during string-pulling (lift, advance, grasp, pull, push) revealed that theta power and frequency peaked during the contralateral paw downward push despite paw speed being low during this action. This suggests that theta frequency and power could respond to effort rather than purely kinematic information. Notably, running-associated theta may similarly reflect both speed and effort as most locomotor tasks conflate these variables. Finally, theta phase aligned from one reach-pull cycle to the next during the downward pull motion - the first action that directly advances the string forward. Since phase-locking has been associated with sensorimotor gating, synchrony at this point could reflect the gating of inputs that are the most causally relevant for reaching the reward, potentially facilitating integration of action-outcome signals for memory encoding and navigation. Taken together, these data support a dual-scale view of hippocampal processing and theta-band activity where macroscale theta activity requires suprathreshold sensory, vestibular, and proprioceptive drive and microscale theta remains sensitive to subsecond limb movements.

Ambient Pollution Components and Sources Associated with Hippocampal Architecture and Memory in Pre-Adolescents
Background: Ambient air pollution poses significant risks to brain health. Hippocampal structure and function are particularly vulnerable, yet the extent to which they are associated with air pollution in children remains unclear. We therefore conducted multi-pollutant mixture analyses to examine how air pollution influences hippocampal architecture and memory performance in late childhood. Methods: We used partial least squares correlation to explore cross-sectional associations between fifteen PM2.5 components, six PM2.5 source factors, NO2, and ozone exposures, and measures of hippocampal microstructure and volume in children aged 9-11 years (n = 7,940) We adjusted for demographic, socioeconomic, and neuroimaging confounds. We also tested whether air pollutants were associated with hippocampal-dependent list-learning memory performance to examine functional implications of air pollution exposure. Shared variance refers to the proportion of total covariance between variable sets captured by each latent dimension in the multivariate relationship. Findings: In the first latent dimension, greater exposure to organic carbon and ozone was associated with differential hippocampal diffusion (72% of shared variance), whereas the second latent dimension linked elemental carbon and iron to hippocampal diffusion (24% of shared variance). Source-based analyses identified biomass burning and traffic pollution as key contributors (61% and 32% variance, respectively). Volumetric analyses revealed higher copper and zinc exposure correlated with smaller hippocampal subregion volumes (left head, right body, tail; 77% variance), whereas lower nickel levels correlated with smaller right head volume (12% variance). Higher industrial and traffic pollutants were also associated with smaller hippocampal volumes (75% variance). We found two latent dimensions (67% and 23% variance, respectively) showing poorer learning, immediate recall, and mnemonic interference performance linked to higher calcium, elemental carbon, and zinc, and organic carbon, alongside lower copper exposure. Finally, hippocampal diffusion (higher free water/lower hindered extracellular diffusion; 83% variance) and smaller tail volumes (96% variance) were linked to poorer RAVLT recall. Interpretation: These results underscore the complex relationship between air pollution exposure and hippocampal architecture and cautions that such structural changes may either presage or reflect subtle differences in neurocomputational mechanisms associated with learning and memory performance in children.

Development of a Novel Benzodiazepine to Delineate Peripheral GABA-A Signaling Mechanisms in Visceral Pain Syndromes
Background and Aims. Visceral pain is a cardinal symptom of many disorders affecting the gut. Modulators of gamma-aminobutyric acid (GABA) such as benzodiazepines may attenuate colonic pain but the specific contribution of peripheral GABAA receptors remains unclear as these agents have prominent central effects. Methods. Using medicinal chemistry optimization of the benzodiazepine scaffold, we developed a novel and potent benzodiazepine-based positive allosteric modulator (PAM) of GABAA receptors, Li633, with no significant central nervous system (CNS) penetration. Results. The locomotor activity of rats placed in an open field was unchanged with Li633 at doses up to 30 mg/kg, confirming its lack of a CNS effect. LI-633 produced robust potentiation of GABA-induced inward current, with EC50 values ranging from 8 nM (5{beta}2{gamma}2) to 128 nM (3{beta}2{gamma}2). In vitro electrophysiological studies confirmed its ability to reduce excitability of human dorsal root ganglion (DRG) neurons. LI-633 potentiated muscimol-induced GABAergic currents in rat DRG neurons in a dose-dependent manner, with an EC50 of 70.4 nM. In vivo, LI-633 significantly attenuated visceral hypersensitivity and pain behavior in a rat model of irritable bowel syndrome (IBS) and functional dyspepsia (FD). In the IBS model, administration of the drug also resulted in decreased excitability of colon-specific DRG neurons and significantly reduced the colonic afferent response to balloon distention as measured by recordings of neural activity in dorsal ganglia rootlets. Conclusions. These findings highlight the potential of targeting peripheral GABAA receptors for pain management in IBS and other disorders associated with visceral hypersensitivity.

Neurological effects induced by micro- and nanoplastics in fish: a systematic review and meta-analysis
Plastic is considered an inert material with high durability and minimal to virtually no decomposition. However, when released into the environment, they can degrade into very small particles, forming micro- and nanoplastic particles (MNP). This systematic review and meta-analysis synthesized the evidence from controlled preclinical studies to investigate the neurological effects of MNPs in fish. Following a pre-registered protocol, we searched PubMed, Web of Science, and Scopus for studies exposing fish to virgin MNPs under controlled conditions, reporting behavioral or neurochemical outcomes relevant to central nervous system function. Data were synthesized using a hierarchical random-effects model with robust variance estimation. Fifty-nine studies, comprising 723 comparisons across 13 behavioral and neurochemical outcomes, were included in the meta-analysis. The analysis accounted for correlated effect sizes within shared control groups; and nested identifiers for study, control group, and effect size. Results indicated high heterogeneity and no consistent effect of the MNP exposure on behavioral or neurochemical parameters, except for reduced traveled distance in sensory-motor assays. Meta-regression examined whether developmental stage, exposure duration, and MNP size or concentration moderate these effects. No significant moderators were identified, except for catalase activity, where longer exposure reduced enzyme activity in larvae. The findings should be interpreted with caution, as reporting quality was generally low, with key methodological details often omitted. Additionally, publication bias was found for several outcomes, and influential case analyses revealed that a few studies disproportionately affected the overall estimates. Further studies are needed to clarify the impact of MNPs on fish neurobiology and behavior.

Childhood Maltreatment and Deviations from Normative Brain Structure: Results from 3,711 Individuals from the ENIGMA MDD and ENIGMA PTSD
Childhood maltreatment (CM), encompassing abuse and neglect, affects over two-thirds of the general population and increases risk for stress-related psychopathology, including major depressive disorder (MDD) and posttraumatic stress disorder (PTSD). The extent to which neuroanatomical alterations in MDD and PTSD are attributable to CM, however, is uncertain. Here, we analyzed CM and 3D structural brain MRI data from 3,711 participants in the ENIGMA MDD and PTSD Working Groups (25 sites; 33.3+/-13.0 years; 59.9% female). Normative modeling estimated deviation z-scores for 14 subcortical volumes (SV), 68 cortical thickness (CT), and 68 surface area (SA) measures, capturing differences from population norms. Transdiagnostic associations between CM and brain deviation scores were evaluated within each sex and age cohort. In young adults (ages 18-35), abuse was associated with larger volumes in thalamus and pallidum, thinner isthmus cingulate and middle frontal regions, and thicker medial orbitofrontal cortex; there were no significant effects in pediatric ([≤]18 years) participants. The strongest effects were observed in young female adults (|{beta}|=.07-.22, q<.05): greater abuse and neglect were correlated with smaller hippocampus and putamen volumes, thinner entorhinal cortex, and smaller SA in fusiform/inferior parietal regions, and with larger SA in orbitofrontal and occipital cortices. In males, abuse had widespread effects on CT and SA (|{beta}|=.1-.18, q<.05); effects for neglect were minimal. Our findings of age- and sex-specific instantiations of CM on brain morphometry highlight the importance of developmental context in understanding how adverse experiences shape neurobiological vulnerability to MDD and PTSD.

Metformin boosts mitochondria and neurogenesis via AMPK/mTOR/SIRT3 in POLG mutant organoids
Background: Mutations in the POLG gene, encoding the catalytic subunit of mitochondrial DNA polymerase gamma, are the most common cause of mitochondrial diseases affecting the central nervous system. These mutations frequently result in neurodevelopmental disorders, yet the cellular and molecular mechanisms underlying POLG related encephalopathies remain poorly understood. In particular, how POLG mutations affect mitochondrial function, neural progenitor behavior, and early neurogenesis in the developing human brain has not been fully elucidated. Methods: To investigate the impact of POLG mutations on human neurodevelopment, we generated 3D cortical brain organoids from induced pluripotent stem cells (iPSCs) derived from a patient carrying compound heterozygous POLG mutations (A467T/W748S). Organoid development was monitored using immunohistochemistry, transmission electron microscopy, and live-cell mitochondrial assays. Single-cell RNA sequencing (scRNA-seq) was performed to profile cellular diversity and transcriptional changes. Organoids were treated with metformin, a known mitochondrial modulator, and mitochondrial function was assessed by measuring membrane potential (TMRE), ATP production, and mtDNA copy number. Western blotting and immunofluorescence were used to investigate AMPK/SIRT3/mTOR signaling and markers of mitochondrial dynamics and mitophagy. Statistical analyses were performed using unpaired t-tests or ANOVA, with p-values < 0.05 considered significant. Results: POLG mutant cortical organoids exhibited impaired neural differentiation, with expansion of stress-associated neural progenitors and reduced neuronal populations. scRNA seq analysis revealed transcriptional signatures of oxidative stress, mitochondrial dysfunction, and suppressed neurogenesis, particularly in a specific neural progenitor subpopulation. Metformin treatment significantly improved mitochondrial membrane potential, ATP output, and mtDNA copy number in POLG organoids. It also promoted neuronal differentiation and reduced reactive progenitor states. Mechanistically, metformin activated AMPK and SIRT3, inhibited mTOR, enhanced expression of mitochondrial fusion and biogenesis markers (OPA1, PGC-1), and increased autophagic and mitophagic activity (LC3B, BNIP3). Conclusions: Our study demonstrates that POLG mutations disrupt early cortical development by impairing mitochondrial function and skewing progenitor fate. Metformin mitigates these effects by restoring mitochondrial homeostasis and promoting neurogenesis through the AMPK/SIRT3/mTOR axis. These findings offer mechanistic insights into POLG-related encephalopathy and support metformin as a candidate for therapeutic intervention in mitochondrial neurodevelopmental disorders.

Multivariate Resting-State Functional Connectivity Features Linked to Transdiagnostic Psychopathology in Early Psychosis
Background: Early psychosis (EP) is characterized by neurobiological changes, including alterations in resting-state functional connectivity (RSFC). We now understand that symptoms and neural changes may overlap across EP diagnostic categories. However, the relationship between RSFC patterns and transdiagnostic symptom dimensions remains poorly understood. Methods: We employed Partial Least Squares correlation to examine multivariate relationships between whole-brain RSFC and clinical symptoms in 124 EP patients (aged 16-35 years) diagnosed with schizophrenia, schizoaffective disorder, or a psychotic mood disorder. RSFC was computed among 216 cortical and subcortical regions. Clinical assessment included 41 symptom measures spanning positive, negative, general psychopathology, and manic dimensions. Results: Analysis revealed one significant latent component (p<0.001) capturing 41.6% of the RSFC-symptom covariance. This component was characterized by increased between-network connectivity, particularly involving sensory-motor, default mode, and subcortical regions including the amygdala and thalamus. The associated symptom profile included cognitive rigidity and arousal dysregulation (stereotyped thinking, anxiety, and somatic concerns), rather than traditional positive or negative symptoms. This brain-behavior relationship was consistent across diagnoses and independent of medication and substance use. The clinical relevance was validated through significant correlations with standardized measures of hostility (r=0.23), negative affect (r=0.25), and perceived stress (r=0.22). Conclusions: Our findings reveal a distinct transdiagnostic phenotype in EP characterized by cognitive inflexibility and arousal dysregulation that is associated with altered integration between sensory, default mode, and subcortical networks. This work suggests that specific patterns of network-level functional connectivity may relate to symptom dimensions that cut across conventional diagnostic boundaries, potentially informing more targeted therapeutic approaches.

Structural insights into wiring specificity in the neuromuscular system through the Beat-Side complex
Nervous system assembly is guided by the actions of cell surface receptors. In Drosophila, members of the Beaten Path (Beat) and Sidestep (Side) protein families have been described as axon guidance receptor-cue pairs, in addition to roles in specifying synaptic connectivity in the optic lobe. To understand the molecular basis and specificity of Beat-Side interactions, we report here the first Beat-Side structure, Beat-Vc bound to Side-VI. The structure showed a binding topology similar to other neuronal immunoglobulin superfamily receptors, especially Nectins, SynCAMs, Dprs and DIPs, despite lack of established evolutionary relationships. Using a structure-based rational approach, we engineered and validated point mutations to break the binding between Beats and Sides. Using these mutant variants, we demonstrated in developing Drosophila larvae that the interaction between Beat-Ia and Side is required for establishing proper connectivity of motor neurons with muscles.

Integrated Profiling of Synaptic E/I Balance Reveals Altered Synaptic Organization and Phenotypic Variability in a Prenatal ASD Model
Proper regulation of excitation and inhibition (E/I balance) is essential for maintaining stable neural circuit function and flexible behavior. Disruptions of E/I balance have been implicated in a variety of neurodevelopmental and psychiatric disorders, including autism spectrum disorder (ASD). However, despite advances in connectomics and molecular neuroscience, how localized disruptions in E/I balance within cortical laminar architectures contribute to behavioral abnormalities remains to be elucidated. Here, we developed a standardized analysis pipeline that combines depth-aligned synaptic mapping, perspective and logarithmic transformations, and multivariate behavioral profiling. Applying this approach to a prenatal valproic acid (VPA) exposure model of ASD, we identified depth-specific disruptions of excitatory and inhibitory synaptic organization within the anterior cingulate cortex (ACC), alongside impairments in social behavior. Principal component analysis (PCA) integrating synaptic and behavioral parameters revealed convergent abnormalities that robustly distinguished VPA-exposed mice from wild-type (WT) controls. Furthermore, although still at an exploratory stage, our findings demonstrate that the robustness of this pipeline enables both the identification of resilient individuals and the quantification of intervention effects. Together, our findings establish a new cross-level analytical framework linking synaptic organization to organismal behavior and provide insights into circuit-level mechanisms underlying ASD-related phenotypes.

Repetitive mild traumatic brain injury causes neuronal damage in the APP/PS1 mouse model of Alzheimer's disease without an enduring impact on amyloid pathology, sleep, or epileptiform activity
Traumatic Brain Injury (TBI) is a known risk factor for Alzheimer's disease and related neurodegenerative diseases. Sleep disturbances and epileptiform abnormalities can appear after TBI and may contribute to the development of neuropathology. In this study, we characterized sleep, epileptiform activity, and neuropathology after repetitive mild traumatic brain injury (rmTBI) in a mouse model of Alzheimer's disease. We used the Closed Head Impact Model of Engineered Rotational Acceleration (CHIMERA) to deliver rmTBI or sham (control) treatment to 6-month-old APP/PS1 mice (n=19). One month post-injury, we implanted electroencephalogram (EEG) and electromyographic (EMG) electrodes, recorded for 72 hours, and then collected brain tissue and blood plasma. Our assessment of sleep architecture showed that time spent in vigilance state was not affected by the rmTBI one month post-injury; however, power spectra analysis showed a statistically significant shift towards higher frequencies in the rmTBI group during non-rapid eye movement (NREM) sleep. Epileptiform activity did not differ between sham and rmTBI. Compared to sham controls, the rmTBI group showed higher neurofilament light (NF-L), but not glial-fibrillary acidic protein (GFAP) in blood plasma and no change in amyloid pathology. These results indicate sustained neurological injury in the APP/PS1 mice one month after rmTBI without affecting amyloid deposition in the brain. Our study suggests that rmTBI can induce neural injury without causing enduring sleep disruption, seizures, and exacerbation of amyloidosis in the APP/PS1 mouse model.

TURBO: Automated Total-body PET Image Processing and Kinetic Modeling Toolbox
ABSTRACT Total-body PET imaging is a novel concept that requires a high level of automatization and standardization, as the large number of target tissues increases manual workload significantly. We introduce an automated analysis pipeline (TURBO) for preprocessing and kinetic modeling of total-body [15O]H2O and [18F]FDG PET data, enabling efficient and reproducible analysis of tissue perfusion and metabolism at regional and voxel level. The approach employs automated CT segmentation for ROI delineation, image-derived input determination, and region-specific PET data kinetic modelling. Methods: We validated the analysis pipeline using Biograph Vision Quadra (Siemens Healthineers) total-body PET/CT scans from 21 subjects scanned with [15O]H2O and 16 subjects scanned with [18F]FDG using six ROIs (cortical brain gray matter, left iliopsoas, right kidney, pancreas, spleen and liver) representing different levels of blood flow and glucose metabolism. Results: Model fits showed good quality with consistent parameter estimates at both regional and voxel levels (R^2 > 0.91 for [15O]H2O, R^2 > 0.99 for [18F]FDG). Estimates from manual and automated input functions were correlated (R^2 > 0.86 for [15O]H2O, and R^2 > 0.88 for [18F]FDG) with minimal bias (<10% for [15O]H2O and <2% for [18F]FDG). Manually and automatically (CT-based) extracted ROI level data showed strong agreement (R^2 > 0.82 for [15O]H2O and R^2 > 0.83 for [18F]FDG), while motion correction had little impact on parameter estimates (R^2 > 0.83 for [15O]H2O and R^2 > 0.88 for [18F]FDG) compared with uncorrected data. Conclusion: Our automated analysis pipeline provides reliable and reproducible parameter estimates across different regions, with average processing time of <180 min per subject. This pipeline completely automatizes total-body PET analysis, reducing manual effort and enabling reproducible studies of inter-organ blood flow and metabolism, including brain-body interactions.

Smelling the Risk: Early Olfactory Deficits, Brain Networks, and Blood Markers of Alzheimers Disease Risk in Humanized APOE Mice
Olfactory impairment is a hallmark of early Alzheimers disease (AD), but the underlying mechanisms connecting sensory decline to genetic and environmental risk factors remain unclear. Our integrative analysis combines ethologically relevant olfactory behavior assays, high-resolution diffusion MRI connectomics, and blood transcriptomics in a large cohort of humanized APOE mice stratified by APOE genotype (APOE2, APOE3, APOE4), age, sex, high-fat diet, and immune background (HN).

Behaviorally, APOE4 mice exhibited accelerated deficits in odor salience, novelty detection, and memory, especially when exposed to a high-fat diet, whereas APOE2 mice showed resilience (ANOVA: APOE x HN, F(2,1669)=77.25, p<0.001, eta squared effect size = 0.08). Notably, age and diet exerted compounding effects, with older and HFD-fed mice displaying reduced odor-guided exploration (diet x age: F(1,1669)=16.04, p<0.001, eta squared effect size = 0.01). Memory analyses revealed robust genotype- and age-dependent impairments: at 24- and 48-hour delays, recognition indices were significantly lower in APOE4 mice compared to APOE2 (long-term memory: APOE x HN, F(2,395)=5.6, p=0.004).

Elastic Net-regularized multi-set canonical correlation analysis (MCCA) linked behavior to brain network substrates, revealing subnetworks whose connectivity explained up to 24 percent of behavioral variance (sum of canonical correlations: 1.27, 95% CI [1.18, 1.85], p<0.0001). High-weighted connections between the ventral orbital cortex, somatosensory cortex, and cerebellar-brainstem pathways were identified as critical nodes for risk or compensation.

Integrative blood transcriptomics revealed eigengene modules strongly correlated with imaging changes in olfactory-memory circuits (for example, eigengene 2 vs. subiculum diffusivity: r = -0.5, p < 1e-30, explaining up to 24 percent of variance). Gene ontology analysis pinpointed shared pathways in synaptic signaling, translation, and metabolic regulation across brain and blood. Notably, glutamatergic and synaptic pathways were enriched among genes linking peripheral and central compartments.

Collectively, these results demonstrate that olfactory behavior, quantitatively shaped by genotype, age, diet, and immune status, serves as a sensitive and translatable early biomarker of Alzheimers disease risk. Our systems-level approach identifies specific brain networks and peripheral molecular signatures underlying sensory-cognitive vulnerability, providing a robust framework for early detection and targeted intervention in AD.

Accumulation of LRRK2-associated phospho-Rab12 degenerative lysosomes in tauopathies
Parkinson's disease (PD) pathogenic mutations in leucine-rich repeat kinase 2 (LRRK2) are associated with endolysosomal dysfunction across cell types, and carriers of LRRK2 mutations variably present with phosphorylated tau and -synuclein deposits in post-mortem analysis. LRRK2 mutations increase the phosphorylation of Rab substrates including Rab12. Rab12 is expressed in neuronal and non-neuronal cells with localization to membranes in the endolysosomal compartment. Under lysosomal stress, LRRK2 interaction with Rab12 upregulates LRRK2 kinase activity. In this study, using a recently developed monoclonal antibody directed to the LRRK2-mediated phosphorylation site on Rab12 at amino acid Ser106 (pS106-Rab12), we test whether aberrant LRRK2 phosphorylation is associated with tau and/or -synuclein pathology across clinically distinct neurodegenerative diseases. Analysis of brain tissue lysates and immunohistochemistry of pathology-susceptible brain regions demonstrate that pS106-Rab12 levels are increased in Dementia with Lewy bodies (DLB), Alzheimer's disease (AD), and PD, and in LRRK2 mutation carriers. In early pathological stages, phosphorylated Rab12 localizes to granulovacuolar degeneration bodies (GVBs), which are thought to be active lysosomal-like structures, in neurons. pS106-Rab12-positive GVBs accumulate with pathological tau stage across brain tissues in DLB, AD, and PD, and in LRRK2 mutation carriers. In a mouse model of tauopathy, pS106-Rab12 localizes to GVBs during early tau deposition in an age-dependent manner. While GVBs are largely absent in neurons with mature protein pathology, subsets of both tau and -synuclein inclusions appear to incorporate pS106-Rab12 at later pathological stages. Finally, pS106-Rab12 labels GVBs in neurons and shows widespread co-pathology with tau inclusions in primary tauopathies including Pick's disease, progressive supranuclear palsy and corticobasal degeneration. These results implicate LRRK2 kinase activity and Rab phosphorylation in endolysosomal dysfunction in both tau and -synuclein-associated neurodegenerative diseases.

Effects of diffusion MRI spatial resolution on human brain short-range association fiber reconstruction and structural connectivity estimation
Short-range association fibers (SAFs) are critical for cortical communications but are often underestimated in conventional resolution diffusion magnetic resonance imaging (dMRI) since they locate within a ~1.5mm thin layer of superficial white matter. With the emergence of sub-millimeter diffusion imaging techniques, this study timely evaluated the effects of image spatial resolution on SAF reconstruction using simulation data and multi-resolution (2, 1.5, and 0.96 mm iso.) empirical data acquired on the same 20 healthy subjects using the gSlider sequence and 20 widely used tractography approaches. Resolution effects were qualitatively assessed through model fitting and tractography results and quantitatively evaluated using global and regional short-range connectivity strength (SCS). It is found that lower resolution systematically reduced SCS across all methods in a spatially varying way. Moreover, tractography methods exhibited significant differences in resolution sensitivity, with diffusion tensor imaging (DTI) based single-tissue single-fiber tractography showing greater vulnerability than constrained spherical deconvolution (CSD)-based multi-tissue multi-fiber tractography, and probabilistic tracking with anatomical constraints (ACT) and filtering (SIFT) improved robustness. Finally, up-sampling data to nominally higher resolution partially mitigated resolution-induced degradation and improved SAF reconstruction accuracy, particularly for DTI tractography. Based on these findings, higher resolution and multi-shell imaging is recommended if possible. For a given dataset, data up-sampling and DTI-based probabilistic tracking with ACT is recommended for single-shell low b-value data. CSD-based probabilistic tracking with ACT and SIFT is recommended for single-shell higher b-value data and multi-shell data. In summary, this study systematically and quantitatively evaluated resolution effects on SAF reconstruction and structural connectivity estimation and provides practical guidelines for more accurate mapping of SAFs that will improve the characterization of healthy and diseased human brains in a wide range of neuroscientific and clinical applications.