N Nature Neuroscience · Dec 05, 2025 The striatal indirect pathway mediates hesitation Hesitation—that is, pausing an action in the face of uncertainty—is ubiquitous in daily life, yet little is known about its underlying neural circuitry. We present a new experimental paradigm that reliably evokes hesitation in mice and find that hesitation is mediated by indirect, but not direct, pathway neurons in the dorsomedial striatum. These data establish a new role for the indirect pathway in suppressing action under uncertainty. Neural circuits Sensorimotor processing biology mouse experiments
N Nature Neuroscience · Dec 04, 2025 In vivo CRISPR screen reveals regulation of macrophage states in neuroinflammation Here we established an in vivo CRISPR screening pipeline using genetically editable progenitor cells to dissect macrophage regulation in mouse models of multiple sclerosis (MS). Screening over 100 cytokine receptors and signaling molecules identified interferon-γ, tumor necrosis factor, granulocyte-macrophage colony-stimulating factor and transforming growth factor-β as essential regulators of macrophage polarization in vivo. Single-cell transcriptomics confirmed that transferred progenitor cells generate all blood-derived CNS myeloid cell populations, enabling Perturb-seq analysis of cytokine actions in neuroinflammation. Combined with biosensor expression, our approach allows monitoring cytokine effects on myeloid cell migration, debris phagocytosis and oxidative activity in vivo. Comparative transcriptomic analyses revealed conserved neuroinflammatory cytokine signatures across myeloid populations, CNS compartments and species, elucidating cytokine cues shaping myeloid function in the cerebrospinal fluid and parenchyma of individuals with MS. This versatile pipeline thus provides a scalable framework for high-resolution analysis of macrophage states and uncovers the cytokine signals that underlie their regulation in MS and MS models. Autoimmunity Monocytes and macrophages Multiple sclerosis Neuroimmunology biology mouse experiments
N Nature Neuroscience · Dec 04, 2025 Rapid motor skill adjustment is associated with population-level modulation of cerebellar error signals A core principle of cerebellar learning theories is that climbing fibers from the inferior olive convey error signals about movement execution to Purkinje cells in the cerebellar cortex. These inputs trigger synaptic changes, which are purported to drive progressive adjustment of future movements. Individually, binary complex spike signals lack information about the sign and magnitude of errors which presents a problem for cerebellar learning paradigms exhibiting fast adaptation. Here, using a newly developed behavioral paradigm in mice, we introduced sensorimotor perturbations into a simple joystick-pulling behavior and found parasagittal bands of Purkinje cells with reciprocal modulation of complex spike activity, along with rapid adaptation of the behavior. Whereas complex spiking showed little modulation in the unperturbed condition, alternating bands were activated or inhibited when the perturbation was introduced and this modulation encoded the sign and magnitude of the resulting sensorimotor mismatch. These findings provide important insight about how the cerebellum uses supervised learning to quickly adapt motor behavior in response to perturbations. Cellular neuroscience Neural circuits biology mouse experiments
N Nature Neuroscience · Dec 02, 2025 The regulatory code of injury-responsive enhancers enables precision cell-state targeting in the CNS Enhancer elements direct cell-type-specific gene expression programs. After injury, cells change their transcriptional state to adapt to stress and initiate repair. Here we investigate how injury-induced transcriptional programs are encoded within enhancers in the mammalian CNS. Leveraging single-nucleus transcriptomics and chromatin accessibility profiling, we identify thousands of injury-induced, cell-type-specific enhancers in the mouse spinal cord after a contusion injury. These are abundant in glial cells and retain cell-type specificity, even when regulating shared wound response genes. By modeling glial injury-responsive enhancers using deep learning, we reveal that their architecture encodes cell-type specificity by integrating generic stimulus response elements with cell identity programs. Finally, through in vivo enhancer screening, we demonstrate that injury-responsive enhancers can selectively target reactive astrocytes across the CNS using therapeutically relevant gene delivery vectors. Our decoding of the principles of injury-responsive enhancers enables the design of sequences that can be programmed to target disease-associated cell states. Astrocyte Epigenetics and plasticity Molecular neuroscience Spinal cord injury biology mouse experiments
N Nature Neuroscience · Dec 02, 2025 High-frequency bursts facilitate fast communication for human spatial attention Brain-wide communication supporting flexible behavior requires coordination between sensory and associative regions but how brain networks route sensory information at fast timescales to guide action remains unclear. Using human intracranial electrophysiology and spiking neural networks during spatial attention tasks, where participants detected targets at cued locations, we show that high-frequency activity bursts (HFAbs) mark temporal windows of elevated population firing that enable fast, long-range communications. HFAbs were evoked by sensory cues and targets, dynamically coupled to low-frequency rhythms. Notably, both the strength of cue-evoked HFAbs and their decoupling from slow rhythms predicted behavioral accuracy. HFAbs synchronized across the brain, revealing distinct cue- and target-activated subnetworks. These subnetworks exhibited lead–lag dynamics following target onset, with cue-activated subnetworks preceding target-activated subnetworks when cues were informative. Computational modeling suggested that HFAbs reflect transitions to population spiking, denoting temporal windows for network communications supporting attentional performance. These findings establish HFAbs as signatures of population state transitions, supporting information routing across distributed brain networks. Attention Biophysical models Cognitive control Perception Sensory processing biology
N Nature Neuroscience · Dec 01, 2025 Oxidized phosphatidylcholines deposition drives chronic neurodegeneration in a mouse model of progressive multiple sclerosis via IL-1β signaling Oxidized phosphatidylcholines (OxPCs) are neurotoxic byproducts of oxidative stress elevated in the central nervous system (CNS) during progressive multiple sclerosis (P-MS). How OxPCs contribute to the pathophysiology of P-MS is unclear. Here we show that stereotactic OxPC deposition in the CNS of mice induces a chronic compartmentalized lesion with pathological features similar to chronic active lesions found in P-MS. Using this model, we found that although microglia protected the CNS from chronic neurodegeneration, they were also replaced by monocyte-derived macrophages in chronic OxPC lesions. Aging, a risk factor for P-MS, altered microglial composition and exacerbated neurodegeneration in chronic OxPC lesions. Amelioration of disease pathology inCasp1/Casp4-deficient mice and by blockade of IL-1R1 indicate that IL-1β signaling contributes to chronic OxPC accumulation and neurodegeneration. These results highlight OxPCs and IL-1β as potential drivers of chronic neurodegeneration in MS and suggest that their neutralization could be effective for treating P-MS. Multiple sclerosis Neuroimmunology biology mouse experiments
N Nature Neuroscience · Nov 26, 2025 Increased neural excitability and glioma synaptic activity drives glioma proliferation in human cortex Adult gliomas are incurable primary brain cancers that infiltrate healthy brain and incorporate into neural networks. Gliomas can be classified as low grade or high grade based on histopathological and molecular features, which broadly predicts their aggressiveness. Here we performed patch-clamp electrophysiological recordings from pyramidal neurons and glioma cells from individuals with either low- or high-grade glioma. We find that the biophysical properties of human pyramidal neurons within glioma-infiltrated cortex differ according to tumor grade, with neurons from high-grade glioma being more excitable than those from low-grade glioma. Additionally, glioma cells within high-grade tumors have smaller, longer synaptic responses. Increased neuron–glioma network activity within human high-grade tumor tissue leads to increased glioma proliferation, suggesting that the hyperexcitability of pyramidal neurons in human high-grade glioma may drive tumor growth. Combined, our findings illustrate that high- and low-grade glioma differentially hijack neural networks. Cancer in the nervous system CNS cancer biology
N Nature Neuroscience · Nov 25, 2025 Trans-ancestry genome-wide analyses of bipolar disorder in East Asian and European populations improve genetic discovery Genome-wide association studies (GWASs) of bipolar disorder (BD) have predominantly included individuals of European (EUR) ancestry, underrepresenting non-EUR populations and limiting insight into disease mechanisms. Here we performed a GWAS of BD in Han Chinese individuals (5,164 cases and 13,460 controls) and conducted comparative and integrative analyses with independent East Asian (EAS, 4,479 cases and 75,725 controls) and EUR (59,287 cases and 781,022 controls) cohorts from the PGC4 GWAS. Our GWAS in EAS ancestry identified two genome-wide significant risk loci, including variants at the major histocompatibility complex (MHC) class II region. Incorporating EAS data into trans-ancestry GWAS revealed 93 significant loci (23 novel). Heritability enrichment analyses implicated a variety of neuronal cell types. Multidimensional post-GWAS prioritization identified 39 high-confidence risk genes, of which 15 were differentially expressed in the brains of patients with BD, 12 modulated BD-relevant behaviors in mice and 18 are pharmacologically tractable. This work advances understanding of the biological underpinnings of BD and provides direction for future research in underrepresented populations. Bipolar disorder Genome-wide association studies biology mouse experiments
N Nature Neuroscience · Nov 24, 2025 A myeloid trisomy 21-associated gene variant is protective from Alzheimer’s disease Alzheimer’s disease causes progressive cognitive decline, yet some individuals remain resilient despite developing hallmark pathology. A subset of people with Down syndrome (DS), the most common genetic cause of Alzheimer’s disease, demonstrates such resilience. Given the elevated risk of hematopoietic mutations in DS, we hypothesize that certain variants may confer microglial resilience. Here, we introduce a myeloid DS-linkedCSF2RBA455D mutation into human pluripotent stem cell-derived microglia from both donors with DS and healthy donors and study their function in 4–10-month-old chimeric mice. We find that this mutation suppresses type I interferon signaling in response to tau pathology, reducing inflammation while enhancing phagocytosis, thereby ameliorating microglial senescence.CSF2RBA455D-expressing microglia form a unique protective subpopulation and preserve neuronal functions. Importantly, they replace diseased wild-type microglia after tau exposure. These findings provide proof of concept that engineered human microglia can enhance resilience against tauopathy, opening avenues for microglial replacement therapies. Alzheimer's disease Induced pluripotent stem cells Microglia Neuroimmunology biology mouse experiments
N Nature Neuroscience · Nov 24, 2025 Munc18 modulates syntaxin phase separation to promote exocytosis The solubleN-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein syntaxin mediates neuronal exocytosis and self-assembles into large clusters in the plasma membrane. The formation and function of these clusters, and whether they promote or inhibit synaptic-vesicle fusion, remain unclear. Here using optogenetic control of syntaxin clustering in vitro and in vivo, as a light-inducible gain-of-function assay, we show that light-enhanced clustering reduces both spontaneous and triggered vesicle fusion, and this impairs mouse hunting behavior. Cluster formation is induced by liquid–liquid phase separation (LLPS) of the SNARE domain of syntaxin. For the regulatory mechanism, Munc18, which is known to alter syntaxin conformation, acts to reduce LLPS for cluster formation, thereby promoting active syntaxin. These results suggest that exocytosis regulation involves LLPS-induced syntaxin clusters that serve as a syntaxin reservoir from which Munc18 captures syntaxin monomers to form a syntaxin–Munc18 complex, setting the stage for efficient fusion. Exocytosis Synaptic vesicle exocytosis biology mouse experiments
N Nature Neuroscience · Nov 24, 2025 The Alzheimer’s therapeutic Lecanemab attenuates Aβ pathology by inducing an amyloid-clearing program in microglia Controversies over anti-amyloid immunotherapies underscore the need to elucidate their mechanisms of action. Here we demonstrate that Lecanemab, a leading anti-β-amyloid (Aβ) antibody, mediates amyloid clearance by activating microglial effector functions. Using a human microglia xenograft mouse model, we show that Lecanemab significantly reduces Aβ pathology and associated neuritic damage, while neither fragment crystallizable (Fc)-silenced Lecanemab nor microglia deficiency elicits this effect despite intact plaque binding. Single-cell RNA sequencing and spatial transcriptomic analyses reveal that Lecanemab induces a focused transcriptional program that enhances phagocytosis, lysosomal degradation, metabolic reprogramming, interferonγgenes and antigen presentation. Finally, we identifySPP1/osteopontin as a major factor induced by Lecanemab treatment and demonstrate its role in promoting Aβ clearance. These findings highlight that effective amyloid removal depends on the engagement of microglia through the Fc fragment, providing critical insights for optimizing anti-amyloid therapies in Alzheimer’s disease. Alzheimer's disease Microglia biology mouse experiments
N Nature Neuroscience · Nov 24, 2025 A mouse brain atlas based on dendritic microenvironments Brain atlases map the spatial organization of neural tissue and serve as anatomical references. Current mouse brain atlases define regions based primarily on cell density patterns but overlook how neurons extend their branches (dendrites) to form local networks. Here we show that mapping dendrites enhanced by their local neighborhoods—which we call microenvironments—reveals a finer-grained brain organization. We analyzed dendrite patterns from more than 100,000 neurons across 111 mouse brains and discovered that neurons group into distinct microenvironments that subdivide known brain regions, nearly doubling the number of identifiable areas compared with the standard Allen Common Coordinate Framework. Remarkably, hippocampal neurons with similar local dendrite arrangements tend to form long-range connections to similar distant targets, suggesting that local structure predicts global connectivity. This microenvironment atlas complements existing resources by revealing previously hidden subdivisions and correlations that align with functional differences, offering new insights into how brain structure relates to function. Computational biology and bioinformatics Neuroscience Systems biology biology mouse experiments
N Nature Neuroscience · Nov 24, 2025 Preconfigured neuronal firing sequences in human brain organoids Neuronal firing sequences are thought to be the building blocks of information and broadcasting within the brain. Yet, it remains unclear when these sequences emerge during neurodevelopment. Here we demonstrate that structured firing sequences appear in spontaneous activity of human and murine brain organoids, both unguided and forebrain identity directed, as well as ex vivo neonatal murine cortical slices. We observed temporally rigid and flexible firing patterns in human and murine brain organoids and early postnatal murine somatosensory cortex, but not in dissociated primary cortical cultures. These results suggest that temporal sequences do not arise in an experience-dependent manner, but are rather constrained by a preconfigured architecture established during neurodevelopment. By demonstrating the developmental recapitulation of neural firing patterns, these findings highlight the potential of brain organoids as a model for neuronal circuit assembly. Developmental neurogenesis Extracellular recording Induced pluripotent stem cells Neurophysiology biology mouse experiments
N Nature Neuroscience · Nov 24, 2025 Large-scale drug screening in iPSC-derived motor neurons from sporadic ALS patients identifies a potential combinatorial therapy Heterogeneous and predominantly sporadic neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), remain highly challenging to model. Patient-derived induced pluripotent stem cell (iPSC) technologies offer great promise for these diseases; however, large-scale studies demonstrating accelerated neurodegeneration in patients with sporadic disease are limited. Here we generated an iPSC library from 100 patients with sporadic ALS (SALS) and conducted population-wide phenotypic screening. Motor neurons derived from patients with SALS recapitulated key aspects of the disease, including reduced survival, accelerated neurite degeneration correlating with donor survival, transcriptional dysregulation and pharmacological rescue by riluzole. Screening of drugs previously tested in ALS clinical trials revealed that 97% failed to mitigate neurodegeneration, reflecting trial outcomes and validating the SALS model. Combinatorial testing of effective drugs identified baricitinib, memantine and riluzole as a promising therapeutic combination for SALS. These findings demonstrate that patient-derived iPSC models can recapitulate sporadic disease features, paving the way for a new generation of disease modeling and therapeutic discovery in ALS. Amyotrophic lateral sclerosis Induced pluripotent stem cells biology
N Nature Neuroscience · Nov 21, 2025 Astrocytic Sox9 overexpression in Alzheimer’s disease mouse models promotes Aβ plaque phagocytosis and preserves cognitive function Astrocytes play essential roles in the brain, and their dysfunction is associated with nearly every form of neurological disease. Despite their ubiquity, knowledge of how astrocytes contribute to disease pathogenesis is incomplete; accordingly, harnessing their biology toward therapeutics remains a major challenge. Here we show that the transcription factor Sox9 plays a context-specific role in maintaining astrocyte function and circuit activity in the aging hippocampus and Alzheimer’s disease (AD) models. We found that Sox9 overexpression in astrocytes in AD models clears existing amyloid beta (Aβ) plaques and preserves cognitive function. Mechanistically, Sox9 promotes the phagocytosis of Aβ plaques by astrocytes through the regulation of the phagocytic receptor MEGF10, which is sufficient to preserve cognitive function in AD models. Collectively, these studies highlight a role for astrocytic Sox9 during aging and AD while identifying Sox9−MEGF10 signaling as a prospective astrocyte-based therapeutic approach to ameliorate cognitive decline in neurodegenerative disease. Alzheimer's disease Astrocyte Cognitive ageing Glial biology biology mouse experiments
N Nature Neuroscience · Nov 20, 2025 Behavioral devaluation by local resistance to dopamine Repeated experiences can cause behavior-specific fatigue. We useDrosophilato study this common form of motivational change, finding that prior matings make males more likely to abandon future copulations when challenged. Here we show that, during mating, dopamine signals through the D2-like receptor (D2R) to promote resilience to challenges that might otherwise cause the male to switch behaviors. This motivating dopamine signal suppresses the output of the copulation decision neurons (CDNs), which can truncate matings when pushed past threshold. Repetition-induced devaluation of mating results from β-arrestin-dependent desensitization of the D2R on the CDNs, rendering them temporarily resistant to naturally released or experimentally supplied dopamine. When local desensitization to dopamine is prevented, the male shows no signs of fatigue, treating each mating as if it were his first. These findings explain a widespread motivational phenomenon and reveal a natural function for the notorious susceptibility of the D2R to drug-induced desensitization. Motivation Sexual behaviour biology
N Nature Neuroscience · Nov 18, 2025 Brain-wide analysis reveals movement encoding structured across and within brain areas Movement-related activity has been detected across much of the brain, including sensory and motor regions. However, much remains unknown regarding the distribution of movement-related activity across brain regions, and how this activity relates to neural computation. Here we analyzed movement-related activity in brain-wide recordings of more than 50,000 neurons in mice performing a decision-making task. We used multiple machine learning methods to predict neural activity from videography and found that movement-related signals differed across areas, with stronger movement signals close to the motor periphery and in motor-associated subregions. Delineating activity that predicts or follows movement revealed fine-scale structure of sensory and motor encoding across and within brain areas. Through single-trial video-based predictions of behavior, we identified activity modulation by uninstructed movements and their impact on choice-related activity analysis. Our work provides a map of movement encoding across the brain and approaches for linking neural activity, uninstructed movements and decision-making. Computational neuroscience Motor control biology mouse experiments
N Nature Neuroscience · Nov 18, 2025 Neural basis of concurrent deliberation toward a choice and confidence judgment Decision confidence plays a key role in flexible behavior and (meta)cognition, but its underlying neural mechanisms remain elusive. To uncover the latent dynamics of confidence formation at the level of single neurons and population activity, we trained nonhuman primates to report a perceptual choice and the associated level of confidence with a single eye movement on every trial. Monkey behavior was well fit by a bounded accumulator model, where choice and confidence are processed concurrently, but not by a serial model, where choice is resolved first, followed by postdecision accumulation for confidence. Neurons in the lateral intraparietal area (LIP) reflected concurrent accumulation, showing covariation of choice and confidence signals across the population, and within-trial dynamics consistent with parallel updating at near-zero time lag. The results demonstrate that the primate brain can process a single stream of evidence in service of two computational goals simultaneously and suggest area LIP as a candidate neural substrate for this ability. Decision Motion detection Neural decoding Psychology other
N Nature Neuroscience · Nov 18, 2025 Spinal cord Tau pathology induces tactile deficits and cognitive impairment in Alzheimer’s disease via dysregulation of CCK neurons Somatosensory processing has been shown to be correlated with brain development and cognitive function, but whether and how tactile sensory deficits affect cognition decline remains unclear. Here we show that tactile function is impaired in individuals with Alzheimer’s disease (AD), and this impairment is inversely correlated with Montreal Cognitive Assessment scores and positively correlated with Tau pathology. We observed similar deficits in presymptomatic 3×Tg AD mice and find that cholecystokinin (CCK)-expressing neurons in the spinal cord are highly vulnerable to Tau pathology. Expressing mutant Tau-P301S in spinal cord CCK-expressing neurons aberrantly activates the transcription factor c-Maf, inhibits CCK neurons and induces tactile deficits, whereas silencing Tau or c-Maf restores tactile sensation and improves cognition in AD model mice. Together, these gain- and loss-of-function studies demonstrate that Tau pathology in spinal cord CCK neurons contributes to tactile dysfunction and cognitive function. Targeting tactile sensation may be a promising strategy for predicting the progression of cognitive impairment in AD. Alzheimer's disease Sensory processing Somatosensory system biology mouse experiments
N Nature Neuroscience · Nov 17, 2025 Distinct transcriptomic and epigenomic responses of mature oligodendrocytes during disease progression in a mouse model of multiple sclerosis Multiple sclerosis (MS) is a chronic autoimmune disease that targets mature oligodendrocytes (MOLs) and their myelin. MOLs are heterogeneous and can transition to immune-like states in MS. However, the dynamics of this process remain unclear. Here, we used single-cell multiome assay for transposase-accessible chromatin and RNA sequencing targeting oligodendroglia (OLG) from the experimental autoimmune encephalomyelitis (EAE) MS mouse model at multiple disease stages. We found that immune OLG states appear at early disease stages and persist to late stages, which can be consistent with epigenetic memory of previous neuroinflammation. Transcription factor activity suggested immunosuppression in OLG at early disease stages. Different MOLs exhibit differential responsiveness to EAE, with MOL2 exhibiting a stronger transcriptional immune response than MOL5/MOL6, and showed divergent responses at the epigenetic level during disease evolution. Our single-cell multiomic resource highlights dynamic and subtype-specific responses of OLG to EAE, which might be amenable to modulation in MS. Animal disease models Chromatin analysis Multiple sclerosis biology mouse experiments
N Nature Neuroscience · Nov 11, 2025 Genetic targeting of premyelinating oligodendrocytes reveals activity-dependent myelination mechanisms To myelinate axons, oligodendrocyte precursor cells (OPCs) must stop dividing and differentiate into premyelinating oligodendrocytes (preOLs), a transient cell stage during myelination that is often stalled at human demyelinating lesions. PreOLs extend processes, surveying nearby axons to begin ensheathment. The lack of genetic tools to visualize and manipulate preOLs has hindered their in-depth study. Here we present a CreERT2knockin mouse line that enables genetic labeling, lineage tracing, manipulation and multimodal profiling of preOL subsets across the central nervous system. Genetically labeled preOLs are postmitotic, with distinct morphology and unique transcriptomic, epigenetic and electrophysiological features. PreOL lineage tracing revealed spatiotemporal dynamics of oligodendrogenesis across the mouse brain. Moreover, fate mapping of preOLs under sensory deprivation revealed that neuronal activity influences preOLs within a narrow maturation window, promoting their survival and successful integration. Together, our work presents a genetic tool to study preOL biology and axon−oligodendrocyte interactions in health and disease. Myelin biology and repair Oligodendrocyte biology mouse experiments
N Nature Neuroscience · Nov 11, 2025 A genome-wide analysis of the shared genetic risk architecture of complex neurological and psychiatric disorders Although neurological and psychiatric disorders have historically been considered to reflect distinct pathogenic entities, recent findings suggest shared pathophysiological mechanisms. However, the extent to which these heritable disorders share genetic influences remains unclear. Here we performed a comprehensive analysis of genome-wide association study data, involving nearly 1 million cases across ten neurological diseases and ten psychiatric disorders, to compare their common genetic signal and biological associations. Using complementary statistical tools, we demonstrate that a large set of common genetic variants impacts the risk of multiple neurological and psychiatric disorders, even in the absence of genetic correlations. Furthermore, genome-wide association studies on psychiatric disorders consistently implicate neuronal biology, whereas neurological diseases are associated with diverse neurobiological processes. Together, this study elucidates the genetic relationship between complex neurological and psychiatric disorders, indicating a larger degree of genetic pleiotropy than previously recognized. The findings have implications for disease classification, precision medicine and clinical practice. Genome-wide association studies Neurological disorders Psychiatric disorders biology
N Nature Neuroscience · Nov 11, 2025 Estrogen modulates reward prediction errors and reinforcement learning Gonadal hormones act throughout the brain and modulate psychiatric symptoms. Yet how hormones influence cognitive processes is unclear. Exogenous 17β-estradiol, the most potent estrogen, modulates dopamine in the nucleus accumbens core, which instantiates reward prediction errors (RPEs), the difference between received and expected reward. Here we show that following endogenous increases in 17β-estradiol, dopamine RPEs and behavioral sensitivity to previous rewards are enhanced, and nucleus accumbens core dopamine reuptake proteins are reduced. Rats adjusted how quickly they initiated trials in a task with varying reward states, balancing effort against expected rewards. Nucleus accumbens core dopamine reflected RPEs that influenced rats’ initiation times. Higher 17β-estradiol predicted greater sensitivity to reward states and larger RPEs. Proteomics revealed reduced dopamine transporter expression following 17β-estradiol increases. Finally, knockdown of midbrain estrogen receptors suppressed sensitivity to reward states. Therefore, endogenous 17β-estradiol predicts dopamine reuptake and RPE signaling, and causally dictates the impact of previous rewards on behavior. Motivation Neural circuits Reward biology estrogen mouse experiments
N Nature Neuroscience · Nov 11, 2025 APOE4toAPOE2allelic switching in mice improves Alzheimer’s disease-related metabolic signatures, neuropathology and cognition Compared to individuals carrying two copies of the ε4 allele of apolipoprotein E (APOE), ε2 homozygotes have an approximate 99% reduction in late-onset Alzheimer’s disease (AD) risk. Here we develop a knock-in model that allows for an inducible ‘switch’ between risk and protective alleles (APOE4s2). Gene expression and proteomic analyses confirm that APOE4s2 mice synthesize E4 at baseline and E2 after tamoxifen administration. A whole-body allelic switch results in a metabolic profile resembling E2/E2 humans and drives AD-relevant alterations in the lipidome and single-cell transcriptome, particularly in astrocytes. Finally, when crossed to the 5xFAD background, astrocyte-specific E4 to E2 switching improves cognition, decreases amyloid pathology, lowers gliosis and reduces plaque-associated apolipoprotein E. Together, these data show that a short-term transition fromAPOE4toAPOE2can broadly affect the cerebral transcriptome and lipidome, and that astrocyte-specificAPOEreplacement may be a viable strategy for future gene editing approaches to simultaneously reduce multiple AD-associated pathologies. Alzheimer's disease Astrocyte Genetic engineering Metabolism biology mouse experiments
N Nature Neuroscience · Nov 10, 2025 Subsecond dopamine fluctuations do not specify the vigor of ongoing actions Dopamine (DA) is essential for the production of vigorous actions, but how DA modifies the gain of motor commands remains unclear. Here we show that subsecond DA transients in the striatum of mice are neither required nor sufficient for specifying the vigor of ongoing forelimb movements. Our findings have important implications for our understanding of how DA contributes to motor control under physiological conditions and in Parkinson’s disease. Basal ganglia Neural circuits biology mouse experiments
N Nature Neuroscience · Nov 06, 2025 Microglia modulate Aβ-dependent astrocyte reactivity in Alzheimer’s disease Experimental evidence suggests that activated microglia induce astrocyte reactivity in neurodegenerative disorders, such as Alzheimer’s disease (AD). In this study, we investigated the association between microglial activation and amyloid-β (Aβ) with reactive astrogliosis in individuals across the AD spectrum. We examined 101 individuals using positron emission tomography radiotracers to assess Aβ deposition ([18F]AZD4694), tau aggregation ([18F]MK-6240) and microglial activation ([11C]PBR28), along with plasma biomarkers for astrocyte reactivity (GFAP) and tau phosphorylation (p-tau217). We further evaluated 251 individuals with cerebrospinal fluid levels of the microglial marker sTREM2. We found that Aβ pathology was associated with astrocyte reactivity across cortical brain regions only in the presence of microglial activation. The microglia-dependent effects of Aβ on astrocyte reactivity were further related to cognitive impairment through tau phosphorylation and aggregation. Our results suggest that microglial activation plays a key role in Aβ-related astrocyte reactivity, which, in turn, contributes to downstream pathological features of AD. Alzheimer's disease Astrocyte Biomarkers Microglia biology mouse experiments
N Nature Neuroscience · Nov 06, 2025 Selective direct influence of motor cortex on limb muscle activity during naturalistic climbing in mice When and how motor cortical output directly influences limb muscle activity through descending projections remain poorly resolved, impeding a mechanistic understanding of motor control. Here we addressed this in mice performing an ethologically inspired climbing behavior. We quantified the direct influence of forelimb primary motor cortex (caudal forelimb area) on muscles across the muscle activity states expressed during climbing. We found that the caudal forelimb area instructs muscle activity pattern by selectively activating certain muscles, while less frequently activating or suppressing their antagonists. From Neuropixels recordings, we identified linear combinations (components) of motor cortical activity that covary with these effects. These components differ partially from those that covary with muscle activity and differ almost completely from those that covary with kinematics. Collectively, our results reveal an instructive direct motor cortical influence on limb muscles that is selective within a motor behavior and reliant on a distinct neural activity subspace. Motor cortex Neural circuits biology mouse experiments
