bioRxiv Subject Collection: Neuroscience's Journal

Broad brain biodistribution conferred by an AAV to restore TDP-43 function mitigates Frontotemporal Demenia-like deficits
TDP-43 dysfunction is an early pathogenic determinant of frontotemporal lobar degeneration with TDP-43 pathology (FTLD-TDP), a devastating disorder currently without effective therapy. Here, we exploit a blood-brain-barrier (BBB)-permeable AAV (AAV-PHP.eB) that confers broad brain biodistribution to restore TDP-43 function in a TDP-43 deficient model (CamKIIa-CreER;Tardbp mice) that mimics the early stage of TDP-43 dysfunction occurring in FTLD-TDP. Intracerebroventricular delivery by AAV-PHP.eB of CTR, our previously characterized splicing repressor, revealed its accumulation in ~40% of adult hippocampal neurons. Remarkably, treatment of adult CamKIIa-CreER;Tardbpf/f mice with AAV-PHP.eB-CTR restored TDP-43 function, attenuated neuronal aberrant activity and memory deficits, and rescued neuron loss. Importantly, we showed that TDP-43's autoregulatory element restricts CTR expression to a physiological range. No overt phenotype was observed after long-term exposure to AAV-PHP.eB-CTR in aged mice, highlighting a favorable safety profile for this gene therapy. These results validate that BBB-crossing AAVs can deliver CTR with a biodistribution in the adult brain that is broad enough to rescue FTD-like phenotypes, supporting clinical testing of this gene therapy for FTLD-TDP.

m6A methylation regulates RNA axonal localisation and translation in developing neurons
Methylation on adenosine N6 (m6A) is an abundant post-transcriptional modification of the RNA that regulates almost the entire lifespan of RNA transcripts, from splicing and nuclear export to RNA stability and translation. Peripheral localisation of RNA is an event common to most cells and especially relevant in neurons where transcripts are trafficked to subcellular compartments to promote growth and differentiation in axons, and synaptic functions in dendrites. Here we show that in developing sympathetic neurons, m6A modification regulates RNA transport and local translation in axons. Critically, Nerve Growth Factor (NGF), a neurotrophin essential for axon growth and neuronal survival, promotes the axonal localisation of methylated transcripts and inhibits protein synthesis of trafficking RNAs, preventing premature protein expression. Noticeably, translation of the bifunctional mRNA Trp53Inp2 depended on the methylation of the 3'UTR, further supporting the key role of m6A modification in determining mRNA fate. Mutation of Trp53Inp2 m6A elements resulted in ectopic translation, defects of axon extension and neuronal death. Together, these data show that m6A is critical for RNA peripheral localisation and spatial regulation of protein expression.

Neurovascular Large artery dilatation increases the risk for Alzheimer's disease pathology
Alzheimer's disease (AD) and related dementia cases are increasing globally, emphasizing the urgent need to clarify disease mechanisms for translational application in diagnoses and treatment. Vascular alterations represent a major pathological feature of AD, and beyond the well-established roles of small vessel disease and large artery atherosclerosis, our group has previously demonstrated that brain large artery dilatation is associated with elevated risk of dementia and Alzheimer pathology. The most severe manifestation of this non-atherosclerotic arterial phenotype is dolichoectasia, an enlargement of large blood vessels (Gutierrez et al., 2019; Melgarejo et al., 2024). Despite consistent epidemiological evidence across populations, the mechanistic link between arterial dilatation and AD remains poorly understood. To address this gap, we induced dolichoectasia in AppNL-G-F mice, a model of amyloid pathology, by injecting elastase into the cisterna magna. After three months, brains were examined using biochemical and immunohistochemical methods. Elastase-treated mice exhibited a significant increase in amyloid plaques in the hippocampus (p = 0.021) and cortex (p = 0.029) compared with vehicle-treated controls. Neuronal loss was evident in the CA1 region of the hippocampus (p = 0.036), with a trend towards neurodegeneration in CA3 (p = 0.055). We also observed elevated p62 in the hippocampus and cortex (p = 0.009 and p = 0.001, respectively), suggesting impaired protein or autophagic-lysosomal clearance. Although no overt increase in neuroinflammation or astrogliosis was detected at this time point, matrix metalloproteinase-9 (MMP-9) levels were trending towards elevated levels (p = 0.058). Combined, these findings indicate successful elastase-induced brain arterial dilatation accelerates AD-related pathology in AppNL-G-F mice, providing mechanistic evidence that large artery dilatation may contribute directly to Alzheimer's disease progression.

Inflexible center-frequency shifts in neural speech tracking are linked to reading and phonological deficits in developmental dyslexia
Developmental dyslexia is marked by persistent deficits in reading and phonological awareness, potentially linked to atypical neural tracking of acoustic speech rhythms at frequencies below 10 Hz. Using magnetoencephalography, we compared adults with developmental dyslexia and matched controls while they listened to speech with varying levels of intelligibility (manipulated via noise vocoding). In controls, decreasing intelligibility led to systematic increases in the tracked frequency of the speech stream, replicating previous findings. This increase in tracking frequency was largely absent in individuals with developmental dyslexia. Unexpectedly, the magnitude of periodic speech tracking in the low frequency range was preserved in DD. Instead, the increase in central tracking frequency was linked to phonological awareness and reading performance.

Decoding the dynamics of cognitive control: Insights from reach movements and electroencephalography
The congruency sequence effect (CSE) refers to improved performance in conflict tasks, such as the Eriksen flanker task, when the congruency of the current trial matches that of the preceding one. Although widely attributed to dynamic adjustments in cognitive control, the neural mechanisms and temporal dynamics underlying this effect remain poorly understood. Here, we combined a release-and-press flanker task with EEG decoding to examine how trial congruency and response type shape behavior and brain activity in healthy adults. Behaviorally, the CSE emerged only when responses repeated, highlighting the dominant role of stimulus-response binding over abstract control mechanisms. Neural decoding mirrored the CSE: current-trial congruency was more reliably decoded on repeated-response trials following congruent versus incongruent trials. This neural CSE was stimulus-locked, occurred between 450-550ms post stimulus onset, and was driven by theta-band activity. More broadly, congruency decoding was particularly robust over frontal channels while cross-temporal generalization indicated transient, sequential neural representations underlying control signals. Together, these findings demonstrate that both behavioral and neural signatures of the CSE are tightly constrained by response repetition and emerge within a narrow temporal window. By integrating reach-based measures with multivariate EEG analyses, this study provides a fine-grained account of when, where, and under what conditions control-related signals unfold after conflict.

Enriched experience increases reciprocal synaptic connectivity and coding sparsity in higher-order cortex
The integration of new information during sleep reshapes cortical representations that support categorical knowledge. Auto-associative attractor network theories predict that reciprocal excitatory connections help form stable categorical attractors, but direct evidence is missing. We tested this using ten weeks of enriched experience (ENR) in mice as a model for knowledge accumulation and recorded single-unit activity across hippocampus and neocortex. ENR induced significant remodeling in high- but not low-level neocortex, with a shift from unidirectional to bidirectional excitatory-excitatory connections, suggestive of increased "cell assemblies". This was accompanied by increased inhibitory-to-excitatory connections and sparser, more orthogonal population activity during awake rest and slow-wave sleep, particularly in deep layers. Thus, ENR reorganizes cortical circuits into a symmetric, inhibition-balanced network that improves coding efficiency, supporting long-standing attractor network predictions.

Single-molecule imaging reveals activity-dependent regulation of Camk2a mRNAs at dendritic spines
Postsynaptic calcium/calmodulin-dependent protein kinase type II (CaMKII) integrates fleeting Ca2+ transients into long-term synaptic potentiation (LTP). A persistent presence of CaMKII at dendritic spines during the maintenance of LTP facilitates the prolongation of synaptic transmission. Yet, it remains unclear how the perpetuation of CaMKII, despite protein turnover, is achieved at dendritic spines. By visualizing endogenous Camk2a mRNAs at single molecule resolution using a newly developed mouse model, we identified a rapid activity-dependent localization of mRNAs to stimulated spines near the postsynaptic density (PSD) of hippocampal neurons. This spine localization was conferred by cis-acting regulatory elements termed cytoplasmic polyadenylation elements (CPEs) in Camk2a mRNA. Spine-localized Camk2a underwent on-site translation, which persisted for extended periods. These findings uncovered a novel local regulation of Camk2a mRNA, which serves to supply dendritic spines with a steady pool of highly concentrated CaMKII for maintaining long-lasting synaptic plasticity.

Adaptor protein complex 2 (AP2) participates in biogenesis and homeostasis of myelin sheaths in the central nervous system
Myelination of CNS axons requires oligodendrocytes to undergo extensive morphological changes by producing large amounts of myelin membrane with defined protein composition and structure. The formation of myelin sheaths thus involves efficient trafficking and sorting of future myelin constituents via vesicles that fuse with prospective myelin membranes by exocytotic mechanisms. However, the functional relevance of other trafficking steps in oligodendocytes for myelin biogenesis is largely unknown. Here, we followed the hypothesis that developmental myelination involves endocytic mechanisms. In this model, Golgi-derived vesicles fuse with the oligodendroglial plasma membrane, from which myelin constituents are retrieved by endocytosis into endosomal/lysosomal organelles before their final integration into the growing sheath. Considering that adaptor protein complex-2 subunit- (AP2M) facilitates AP2-dependent endocytosis, we recombined the Ap2m-gene in myelin-forming oligodendrocytes, causing both hypomyelination and specific changes in the myelin proteome. Most strikingly, lysosomal membrane proteins accumulate in the abaxonal (outermost) myelin layer, identifying this membrane as an active site for retrieving constituents from myelin sheaths. These data demonstrate that the AP2 complex serves a critical function in developmental myelination in vivo. Unexpectedly, we also observed pathological myelin outfoldings indicative of focal hypermyelination. Consistent with the hypothesis that this phenotype reflects impaired maintenance rather than biogenesis of myelin sheaths, recombination of the Ap2m-gene in oligodendrocytes of adult mice caused late-onset progressive focal hypermyelination. These results indicate that, in addition to astrocytic and microglial phagocytosis, oligodendrocytes cell-autonomously contribute to maintaining the structure of healthy myelin sheaths via AP2-dependent mechanisms.

Memory-Related Default-Executive Coupling Across the Lifespan and Associations with Changes in Cognitive Control
Episodic memory and cognitive control declines in aging. The default-executive coupling hypothesis of aging (DECHA) suggests that a neural correlate of cognitive decline in aging is increased functional connectivity (FC) between lateral prefrontal areas and the default mode network. Here, in a lifespan sample (n=552, 6-81years), we tested FC between the left dorsolateral prefrontal cortex (dLPFC) and the default mode network (DMN) during the encoding and retrieval phases of an episodic memory fMRI task. We created two age groups based on evidence for episodic memory decline after 30 years: a youth group encompassing childhood, adolescence, and young adulthood (6-29 years) and an aging group (30-81 years). To test if the dLPFC-DMN FC was associated with changes in cognitive control, we used longitudinal change (up to 10 years) in a Stroop inhibition/switching task linked to the prefrontal cortex. Results showed (i) lower dLPFC and DMN connectivity with age in the youth group and higher connectivity in the aging group, and (ii) this FC was associated with an age-related increase in the inhibition task completion time, particularly in the aging group. However, dLPFC showed similar relationships with other networks, particularly salient attentional and control subnetworks, and despite decline in cognitive control associated with memory performance, memory-related FC between dLPFC and DMN did not. Although this link with memory performance remains unclear, the results using longitudinal cognitive data align with the DECHA mechanisms and extends the current proposal by indicating inverse relationships in development and the relevance of additional attentional and control network coupling.

Stress-Responsive Transcriptomic Signatures in Human iPSC-Derived Microglia Reveal Links to Alzheimer's Disease Risk Genes
Cellular stress responses are essential for maintaining homeostasis in the face of environmental or internal challenges. In the central nervous system, microglia serve as key stress sensors and immune responders, shaping neuroinflammatory processes and disease progression. However, the molecular programs engaged by distinct stressors and their impact on microglial viability remain incompletely understood. In this study, we used human induced pluripotent stem cell-derived microglia-like cells to investigate stress responses to amyloid beta, a chronic Alzheimer's disease-related stressor, and lipopolysaccharide (LPS), a classical acute inflammatory stimulus. Using single-cell RNA sequencing, we mapped the transcriptional programs activated by each condition and benchmarked these states against reference microglial datasets from mouse and human brains. In parallel, we performed a pooled CRISPR interference screen targeting Alzheimer's disease-associated microglial genes to identify genetic determinants of microglial survival. We found that amyloid beta and LPS elicit partially overlapping but distinct transcriptional responses. amyloid beta induced more focused and disease-associated gene expression changes, while LPS triggered broad inflammatory activation and stronger cell death signatures. A subset of genes activated by stress overlapped with Alzheimer's disease risk genes and with hits from the survival screen, suggesting that disease-associated microglial genes may contribute to stress adaptation and cellular fitness. These results demonstrate that iPSC-derived microglia-like cells can recapitulate in vivo-like stress-responsive states and offer a tractable platform to investigate genetic and environmental influences on microglial behavior. Together, our findings reveal transcriptional programs that link stress sensing, survival regulation, and Alzheimer's disease-associated gene networks, providing a foundation for future efforts to enhance microglial resilience in neurodegenerative disease contexts.

Regulatory logic of neuronal identity specification in Drosophila
During neurogenesis, signaling molecules and transcription factors (TFs) pattern neural progenitors across space and time to generate the numerous cell types that constitute neural circuits. In postmitotic neurons, these identities are established and maintained by another class of TFs known as terminal selectors (tsTFs). However, it remains largely unclear how the tsTF combinations are specified in newborn neurons, and how they then coordinate the type-specific differentiation programs of each neuron. To investigate these regulatory mechanisms, we performed simultaneous single-cell RNA and ATAC sequencing experiments on the Drosophila optic lobes and identified over 250 distinct cell types at four stages of their development. We characterized the common cis-regulatory features of neuronal enhancers and performed comprehensive inference of gene regulatory networks across cell types and stages. Our results reveal cooperative actions of pan-neuronal and tsTFs on cell type-specific enhancers, and that same effector genes are often regulated by different TF combinations in different cell types. During neurogenesis, patterning TFs are associated with different accessible enhancers before and after cell cycle exit, allowing them to be re-utilized as tsTFs independently from their earlier roles in progenitors. We show that expression of tsTFs Vsx1/2 in a variety of optic lobe neurons is mediated by lineage-specific enhancers, each patterned by different upstream mechanisms. Therefore, neuronal identity specification is a multi-step regulatory program wherein the same TFs can enact distinct regulatory codes at different steps and across cell types.

Aging alters the distribution, stability, and transcriptional signature of engram cells
While aging impairs memory precision, its effects on engram dynamics and gene expression remain poorly understood. To address this, we used TRAP2 activity-reporter mice, nuclear tagging, and FOS-based activity mapping to track neurons activated during contextual fear memory encoding and reactivated during recall in young and aged mice. Across 378 brain regions, we quantified engram size, spatial distribution, and reactivation stability. We further applied fluorescence-activated nuclear sorting (FANS) combined with single-nucleus RNA sequencing (snRNA-seq) to characterize gene expression changes associated with memory encoding and recall across diverse cell types. In addition, we compared the transcriptional profiles of first-time versus second-time neuronal responder cells in the dentate gyrus. Aged brains exhibited altered engram allocation, reduced reactivation stability, and distinct gene expression patterns during memory retrieval. These findings reveal age-related changes in the organization and molecular identity of memory traces, providing mechanistic insight into cognitive decline and highlighting potential targets for intervention.

Atypical developmental remodeling of dopamine neurons involves AKT-GSK3β signaling and glia-mediated axon degeneration
Neuronal remodeling is essential for sculpting neural circuits, and its disruption has been implicated in neurodevelopmental and neuropsychiatric disorders. Yet the molecular and cellular diversity of remodeling across neuron types remains incompletely understood. Here, we uncover a distinct remodeling mode in a subtype of Drosophila dopamine neurons (DANs) critical for learning, memory, sleep, and locomotion. Unlike the stereotypical pruning-then-regrowth paradigm, these DANs undergo a transient axon overgrowth followed by selective pruning during metamorphosis. Remarkably, DAN axon pruning proceeds independently of canonical ecdysone signaling and instead involves neuron-intrinsic AKT-GSK3{beta} signaling and extrinsic glial activity. Disruption of AKT-GSK3{beta} signaling alters microtubule stability and impairs glial recruitment and clearance of axonal debris. Notably, the role of AKT-GSK3{beta} is cell-type specific, underscoring mechanistic diversity in remodeling programs. These findings reveal an unexpected overgrowth-then-pruning developmental trajectory, establishing DANs as a powerful model to uncover the mechanisms underlying neuronal remodeling, circuit maturation, and neurodegeneration.

Mitochondrial DNA damage in substantia nigra parscompacta astrocytes exacerbates dopaminergic neuron lossin a 6-hydroxydopamine mouse model of parkinsonism
Parkinsons disease (PD) is the fastest growing neurological disorder with no known cure. Our ability to develop disease-modifying treatments that slow down the loss of substantia nigra pars compacta (SNc) dopaminergic (DA) neurons is hindered by a dearth of knowledge on roles for non-neuronal elements such as astrocytes during PD pathogenesis. More specifically, the extent to which mitochondrial DNA (mtDNA) damage in SNc astrocytes contributes to SNc DA neuron loss during PD remains unknown. To address this knowledge gap, we utilized an adeno-associated virus (AAV) called Mito-PstI that expresses the restriction enzyme PstI as an approach to damage mtDNA in SNc astrocytes and assess the effect of astrocytic mtDNA damage on SNc DA neuron function and viability in mice. Mito-PstI-induced mtDNA damage in SNc astrocytes disrupted mitochondrial morphology, caused increased wrapping of SNc astrocytic processes around SNc DA neurons, and abnormally increased dopamine release by SNc DA neuron axonal terminals within the dorsolateral striatum (DLS). In addition, mice injected with Mito-PstI in the SNc showed increased spontaneous and apomorphine-induced rotations contralateral to the side with SNc Mito-PstI injections. In further experiments, we used a parkinsonian mouse model with low dose 6-hydroxydopamine (6-OHDA) injection into the DLS to show that Mito-PstI expression in SNc astrocytes caused a worsening of 6-OHDA-induced spontaneous contralateral rotational behavior, and exacerbated SNc DA neuron loss. These results suggest that mitochondria in SNc astrocytes are not only critical for the function of SNc DA neurons, but are also a new target for developing disease-modifying strategies against PD.

A common Iba1 antibody labels vasopressin neurons in mice
There are a wide variety of commercially available antibodies for labeling microglial cells based on different protein targets, as well as antibodies for the same protein target made in different species. While this array of targets and hosts allows for flexibility in immunohistochemical experiments, it is important to validate that different antibodies provide comparable and accurate immunodetection prior to experimental data collection. We found that a commercially available anti-Iba1 antibody, made in goat, produces irregular staining patterns in specific regions of the mouse brain, prompting a further investigation into the phenomenon. This Iba1-goat antibody displayed increased numbers of labeled cells when compared to expression of a CX3CR1-GFP reporter and IHC detection of P2RY12, two common microglial markers. Furthermore, immunodetection by other common anti-Iba1 antibodies made in rabbit and chicken did not display the excessive cell labeling when compared to the CX3CR1-GFP reporter. Upon further investigation, this Iba1-goat antibody was observed to highly colocalize with vasopressin neurons in the paraventricular nucleus of the hypothalamus (PVN) and the supraoptic nucleus of the hypothalamus (SON), the two main sites of vasopressin production in the brain. Other anti-Iba1 antibodies made in other species did not show this same colocalization with vasopressin. Finally, this effect was species-specific, as Wistar rats did not display erroneous cell labeling by the Iba1-goat antibody. In sum, the present study employs both qualitative and quantitative data to highlight the importance of validating antibody efficacy and specificity in a region- and species-specific manner.

Targeted degradation of pathogenic TDP-43 proteins in amyotrophic lateral sclerosis using the AUTOTAC platform
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive loss of motor neurons and the cytoplasmic aggregation of misfolded proteins in the spinal cord, including TAR DNA-binding protein-43 (TDP-43). More than 97% of ALS cases exhibit pathological TDP-43 inclusions, yet therapeutic strategies that can selectively eliminate these aggregates remain yet to be developed. Here, we employed the AUTOTAC (Autophagy-Targeting Chimera) to degrade TDP-43 aggregates via macroautophagy mediated by the N-recognin p62/SQSTM1 of the N-degron pathway. The AUTOTAC degraders ATC141 and ATC142 were designed to bind and link the oligomeric species of misfolded TDP-43 to p62, which induces the targeting of TDP-43 cargoes to phagophores for lysosomal co-degradation, while sparing monomeric TDP-43. ATC142 induced the degradation of pathological TDP-43 A315T species and its cleaved variant, TDP-25, with DC50 values of 1.25-9.6 nM. In ALS model mice expressing TDP-43 A315T in the spinal cord, oral administration of 10 mg/kg ATC141 with 24 doses reduced TDP-43 aggregates as well as GFAP+ astrocytes and Iba1+ microglia. ATC141 also exerted disease-modifying efficacy to reverse the disease progression in neuromuscular coordination and cognitive function. This oral drug is under Phase 1 clinical trials in South Korea with 76 healthy volunteers aiming to treat ALS, Alzheimer's diseases (AD), and progressive supranuclear palsy (PSP). We suggest that AUTOTAC provides a novel strategy to treat a broad range of neurodegenerative diseases.

Characterizing representational shaping of individual motor and object representations after sequence learning
Learning temporal regularities between pairs of events has been shown to shape neural representations in the medial temporal lobe, but it remains unclear whether representational changes generalize across memory domains. Here we used fMRI and multivoxel pattern similarity analyses to examine representational shaping as a consequence of motor and object sequence learning. Across two sessions, participants incidentally learned a fixed four-element sequence of finger movements or visual objects. We compared the pattern of blood oxygen level-dependent activity evoked by each object and finger movement before and after sequence learning. Analyses were performed on bilateral ROIs, including primary motor cortex (M1), lateral occipital complex (LOC), premotor cortex (PMC), striatum (STR) and the hippocampus (HC). Behaviorally, participants successfully learned the sequence in both domains. At the neural level, motor representations became more differentiated with learning in M1, PMC, STR, and HC, but not in LOC. This global differentiation was not specific to the sequence condition and was also observed after repeated co-occurrence of movements in a pseudorandom order. Critically, the HC differentiated between motor representations in the learned sequence in a unidirectional predictive manner whereby movements became more differentiated from the preceding than from the following element in the sequence. In contrast, object representations remained stable across sequence repetitions in all brain regions, even though participants successfully learned their temporal order.

Limited generalizability of dynamic fMRI correlates of adolescent rumination
Rumination, or perseverative negative self-referential thinking, is a hallmark of depression. In adults, a dynamic resting-state fMRI model of trait rumination was recently identified through predictive modelling. In adolescents, a development period during which rumination and depression increase, the neurobiological correlates of ruminative thinking are less clear. In the current preregistered study, we examine dynamic connectivity correlates of self-reported rumination in the largest sample of adolescents to date (n = 443, containing clinical and non-clinical individuals). Notably, the adult model failed to generalize to our sample. In addition, linear models trained on default-mode network (DMN) connectivity, as well as whole-brain connectome models, failed to generalize to held-out data. In an exploratory random forest analysis, we found significant prediction performance of a model where increased variability between DMN-cerebellum, DMN-dorsal attention network, and DMN-DMN connections was nominally associated with higher rumination. However, the model did not generalize to an external sample with lower rumination scores and a distinct scanner protocol. Our findings illustrate the difficulty of characterizing the neurodevelopment of risk factors for depression.

The Gut-Brain Axis Shapes Cognitive-Emotional Processing: Evidence for Attentional Avoidance of Bloating Cues in IBS
Background: Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by significant gut-brain interactions and various symptoms such as abdominal pain, bloating, and altered bowel habits. Cognitive deficits in IBS have been linked to attentional biases, particularly towards somatic and symptom-related cues. Despite increasing interest in understanding these cognitive processes, the specific patterns of attentional biases and their relationship with anxiety in IBS remain inadequately explored. Method: This study employed a dot-probe task to compare attentional biases toward somatic (bloating, pain) and social threat cues (angry/disgusted faces) in 15 patients with IBS, 15 individuals with high anxiety (HA) and 15 healthy controls (HC). Participants completed two tasks (Body/Face) with 500 ms stimulus exposure. Attentional bias indices were analyzed using mixed-design ANOVAs controlling for anxiety (STAI) and IBS symptom severity (IBS-SSS). Results: Patients with IBS exhibited significant avoidance of bloating-related stimuli compared to HC (p = .013), but not pain-related cues. Anxiety modulated attentional processing in IBS (p = .015) and HC (p = .013). HA showed no significant biases. IBS patients demonstrated slower overall reaction times than HC (p= .024), suggesting cognitive load. A positive IBS severity-anxiety correlation was observed in IBS (r = 0.574 p = .020). Conclusions The findings demonstrate that IBS is associated with selective avoidance of bloating-related stimuli, driven by a maladaptive interplay between hyper-precise symptom expectations and interoceptive noise a mechanism distinct from anxiety-related attentional patterns. While anxiety amplifies this avoidance, it does not independently account for the cognitive profile of IBS. These results underscore the gut-brain axis role in shaping cognitive-emotional processing.

The Brain/MINDS 3D Digital Marmoset Brain Atlas Version 2.0: Population-based Cortical Region Parcellations with Multi-Modal Standard Templates
We present the Brain/MINDS population-based 3D digital brain atlas version 2.0 (BMA2.0), a population-based 3D digital brain atlas of the common marmoset (Callithrix jacchus), designed to overcome limitations of previous single-subject atlases that are prone to structural biases arising from individual variation. This release integrates manually delineated cortical regions from 10 myelin-stained brains to generate a generalized cortical parcellation. Subcortical regions from a previous version (BMA2017) and a state-of-the-art cerebellum atlas (University of Pittsburgh) were also incorporated, resulting in a comprehensive whole-brain parcellation of 636 regions. To enhance cross-modal registration accuracy, we implemented artificial intelligence (AI)-based techniques, including CycleGAN and Pix2Pix for image translation and segmentation. These methods enabled accurate alignment across myelin, Nissl, block-face, and MRI modalities by providing both visual similarity and anatomically meaningful constraints. The atlas package includes population-average templates for myelin and Nissl staining (based on 10 individuals), a new ex vivo MRI standard space constructed from 91 brains, and an in vivo average brain from 446 individuals. Additionally, flat map projections and surface models (outer, mid, and inner cortical layers) are provided, facilitating multi-modal integration and spatial analysis. While applications such as quantification of laminar thickness are demonstrated, BMA2.0 is designed as a general-purpose platform for cross-modal registration, data integration, and comparative neuroscience. It supports spatially grounded analysis of marmoset brain structure and function and offers broad compatibility with existing datasets and software.