Biology subjects

Kempermann, G.

Publications and source records attributed to Kempermann, G..

At least 19 recordsLinked to original sources

bioRxiv2026

Mice sense Moon and Sun

Life on earth has always been exposed to the fluctuating Earth's magnetic field, but a magnetic sense affecting behavior has been debated for mammals. We here report that mice, kept under constant laboratory conditions, showed fluctuations in spontaneous behavioral activity with a periodicity of ~14 and ~28 days. This was confirmed in nine cohorts from four facilities on two continents, covering 3 to 41 months. Such oscillations were also maintained in brain Bmal1 knockout mice lacking circadian rhythms, suggesting independence of the circadian clock. The behavioral activity peaked around full and new Moon, and showed a strong alignment with the periodic geomagnetic fluctuations originating in the Earth's iono- and magnetosphere that are modulated by solar rotation and the orbital motion of the Moon. In the ultradian range, this alignment persisted in CRY1/2 knockout mice, suggesting that solar-lunar-driven geomagnetic fluctuations can modulate behavior rhythms independently of CRY1/2.

neuroscience↗

bioRxiv2026

Co-option of CENP-A for activity-induced neuronal plasticity

Neuronal activation drives activity-dependent gene expression that underlies experience-associated synaptic modifications, learning and memory. Here we show that the histone variant CENP-A, best known for specifying centromere identity, is dynamically regulated by synaptic activity at both the RNA and protein levels in postmitotic neurons. Neuronal activation increases a non-centromeric nuclear pool of CENP-A while leaving centromeric CENP-A levels unchanged. Downregulation of CENP-A selectively reduces the activity-associated non-centromeric pool, impairs activity-dependent induction of immediate-early genes such as FOS and ARC, and disrupts hippocampus-dependent learning and memory. Furthermore, we find that activity-dependent neuronal responses in human embryonic stem cell-derived forebrain organoids similarly require CENP-A. Our results reveal a mitosis-independent, conserved role of CENP-A for driving plasticity in mammalian neurons.

neuroscience↗

bioRxiv2026

Experience Reorganizes Coordinated Population Dynamics Across Hippocampal Circuits

Hippocampal function relies on structured patterns of population activity that reflect the intrinsic organization of the circuit. Although experience is known to influence synaptic properties and local activity features, whether prolonged experience reshapes the large-scale organization of population dynamics across hippocampal subfields in the intact brain has remained unclear. Progress on this question has been limited by the lack of measurements that capture circuit-wide activity simultaneously while preserving spatial circuit structure. Here, we combined prolonged environmental experience with large-scale, simultaneous multi-shank recordings spanning CA1, CA3, and dentate gyrus in the mouse hippocampus to examine experience-dependent changes in circuit dynamics. We find that long-term experience reorganizes the basal operating state of the hippocampus, altering the statistical structure of field potentials, population spiking, and sharp-wave ripple activity in a coordinated manner across subfields. These changes are not confined to specific regions but instead reflect a circuit-wide reconfiguration of functional interactions that extends over larger spatial scales. At the population level, experience shifts hippocampal dynamics into a more coordinated dynamical regime, characterized by shared low-dimensional structure across hippocampal subfields. Together, these findings demonstrate that long-term experience reorganizes coordinated population dynamics across hippocampal circuits, establishing an intrinsic activity organization that reflects the experiential history of a memory network.

neuroscience↗

bioRxiv2024

Mapping Large-scale Spatiotemporal Dynamics of Synaptic Plasticity and LTP for Memory Encoding in the Hippocampal Network

Understanding memory formation requires elucidating the intricate dynamics of neuronal networks in the hippocampus, where information is encoded and processed through specific activity patterns and synaptic plasticity. Here, we introduce "EVOX," an advanced network electrophysiology platform equipped with high-density microelectrode arrays to capture critical network-level synaptic dynamics integral to learning and memory. This platform surpasses traditional methods by enabling label-free, high-order mapping of neural interactions, providing unprecedented insights into network Long-Term Potentiation (LTP) and evoked synaptic transmission within the hippocampal network. Utilizing EVOX, we demonstrate that high-frequency stimulation induces network-wide LTP, revealing enhanced synaptic efficacy in previously inactive cell assemblies in hippocampal layers. Our platform enables the real-time observation of network synaptic transmission, capturing the intricate patterns of connectivity and plasticity that underpin memory encoding. Advanced computational techniques further elucidate the mesoscale transmembrane generators and the dynamic processes that govern network-level memory encoding mechanisms. These findings uncover the complex dynamics that underlie learning and memory, showcasing EVOXs potential to explore synaptic and cellular phenomena in aging circuits. EVOX not only advances our understanding of hippocampal memory mechanisms but also serves as a powerful tool to investigate the broader scope of neural plasticity and network interactions in healthy and diseased states.

neuroscience↗

bioRxiv2024

MEA-seqX: High-resolution Profiling of Large-scale Electrophysiological and Transcriptional Network Dynamics

Concepts of brain function imply congruence and mutual causal influence between molecular events and neuronal activity. Decoding entangled information from concurrent molecular and electrophysiological network events demands innovative methodology bridging scales and modalities. Our MEA-seqX platform, integrating high-density microelectrode arrays, spatial transcriptomics, optical imaging, and advanced computational strategies, enables the simultaneous recording and analysis of molecular and electrical network activities at the level of individual cells. Applied to a mouse hippocampal model of experience-dependent plasticity, MEA-seqX unveiled massively enhanced nested dynamics between transcription and function. Graph-theoretic analysis revealed an increase in densely connected bimodal hubs, marking the first observation of coordinated spatiotemporal dynamics in hippocampal circuitry at both molecular and functional levels. This platform also identified different cell types based on their distinct bimodal profiles. Machine-learning algorithms accurately predicted network-wide electrophysiological features from spatial gene expression, demonstrating a previously inaccessible convergence across modalities, time, and scales.

neuroscience↗

bioRxiv2024

Genetic Modulation of Protein Expression in Rat Brain

Genetic variations in protein expression are implicated in a broad spectrum of common diseases and complex traits. However, the fundamental genetic architecture and variation of protein expression have received comparatively less attention than either mRNA or classical phenotypes. In this study, we systematically quantified proteins in the brains of a large family of rats using tandem mass tag (TMT)-based quantitative mass-spectrometry (MS) technology. We identified and quantified a comprehensive proteome of 8,119 proteins from Spontaneously Hypertensive (SHR/Olalpcv), Brown Norway with polydactyly-luxate (BN-Lx/Cub), and 29 of their fully inbred HXB/BXH progeny. Differential expression (DE) analysis identified 597 proteins with significant differences in expression between the parental strains (fold change > 2 and FDR < 0.01). We characterized 95 variant peptides by proteogenomics approach and discovered 464 proteins linked to strong cis-acting quantitative trait loci (pQTLs, FDR < 0.05). We also explored the linkage of pQTLs with behavioral phenotypes in rats and examined the sex-specific pQTLs to reveal both distinct and shared cis-pQTLs between sexes. Furthermore, by creating a novel view of the rat pangenome, we improved the ability to pinpoint candidate genes underlying pQTL. Finally, we explored the connection between the pQTLs in rat and human disorders, underscoring the translational potential of our findings. Collectively, this work demonstrates the value of large and systematic proteo-genetic datasets in understanding protein modulation in the brain and its functional linkage to complex central nervous system (CNS) traits.

genetics↗

bioRxiv2024

Exploring social modulation: Microglia as a key mediator of individual immune response, plasticity and pathology in App-NL-G-F mouse model of Alzheimer's disease

This study explores the influence of lifestyle on Alzheimers disease (AD) progression using App-NL-G-F mice in a complex enrichment system. Mice exhibited social deficits before plaque pathology or memory impairment, revealing a crucial link between lifestyle, behavior, and neuroinflammation. Plasma analysis indicates early inflammation and apoptosis-related changes, setting the stage for identifying markers predicting plaque manifestation. Beyond pathology, social behavior is linked to adult neurogenesis and microglia coverage, forming a dynamic connection with microglia activation. Further, sc-RNA sequencing unveiled a decrease in interferon-responsive microglia and alteration in antigen processing with enrichment. These findings underscore the beneficial impact of social housing on microglia and interconnected factors, pointing to microglia as a critical mediator of the behavior-pathology-plasticity interplay in AD. The study enhances our understanding of AD complexity and offers insights into potential therapeutic strategies, emphasizing the multifaceted nature of AD progression and the role of lifestyle in shaping its course.

neuroscience↗

bioRxiv2023

Early-life experience determines the social stability of adult communities in female mice

Early social interactions critically shape lifelong individual behaviour but their development and stability have been difficult to study in laboratory settings. Our experimental platform allows the automated real-time and longitudinal study of social structure in mice living in a shared environment, providing previously inaccessible behavioural measures. These include estimates of directed agonistic activity for the reconstruction of social hierarchies and their dynamics over the life-course. In an all-female colony of genetically identical mice, pairwise inter-individual interactions revealed stable dominance hierarchies that already emerged early in life. Older animals introduced into a new colony exhibited a steeper hierarchy compared to adolescent mice or mature mice that had been co-housed throughout life. Our longitudinal analysis of social dominance hierarchies highlights the critical role of early-life experience. One-Sentence SummaryAutomated tracking of mouse colonies revealed differences in social structure dependent on the animals early-life experience.

animal behavior and cognition↗

bioRxiv2023

Polyglucosan body density in the aged mouse hippocampus is controlled by a novel modifier locus on chromosome 1

In aged humans and mice, aggregates of hypobranched glycogen molecules called polyglucosan bodies (PGBs) accumulate in hippocampal astrocytes. PGBs are known to drive cognitive decline in neurological diseases but remain largely unstudied in the context of typical brain aging. Here, we show that PGBs arise in autophagy-dysregulated astrocytes of the aged C57BL/6J mouse hippocampus. To map the genetic cause of age-related PGB accumulation, we quantified PGB burden in 32 fully sequenced BXD-recombinant inbred mouse strains, which display a 400-fold variation in hippocampal PGB burden at 16-18 months of age. A major modifier locus was mapped to chromosome 1 at 72-75 Mb, which we defined as the Pgb1 locus. To evaluate candidate genes and downstream mechanisms by which Pgb1 controls the aggregation of glycogen, extensive hippocampal transcriptomic and proteomic datasets were produced for aged mice of the BXD family. We utilized these datasets to identify Smarcal1 and Usp37 as potential regulators of PGB accumulation. To assess the effect of PGB burden on age-related cognitive decline, we performed phenome-wide association scans, transcriptomic analyses as well as conditioned fear memory and Y-maze testing. Importantly, we did not find any evidence suggesting a negative impact of PGBs on cognition. Taken together, our study demonstrates that the Pgb1 locus controls glycogen aggregation in astrocytes of the aged hippocampus without affecting age-related cognitive decline.

genetics↗

bioRxiv2022

Pre-symptomatic reduction of individuality in the App NL-F knock-in model of Alzheimer's disease

While one third of the risk for Alzheimers disease (AD) is explained by environment and lifestyle, AD pathology also affects individual lifestyle, possibly long before clinical manifestation of dementia. To study this hidden disease effect with its potentially large impact on coping with AD, we examined in mice how the AppNL-F/NL-F (NL-F) knock-in mutation affects the pre-symptomatic response to environmental enrichment (ENR). We assessed the emergence of inter-individual phenotypic variation while both genetic background and the shared environment were held constant, thereby isolating the contribution of individual behavior ( non-shared environment). After 4 months of ENR, in NL-F both mean and variability of plasma ApoE were increased, suggesting a pre-symptomatic variation in pathogenic processes. Roaming entropy (RE) as a measure of behavioral activity was continuously assessed with radiofrequency identification (RFID) technology and revealed reduced habituation and variance in NL-F compared to controls. Intra-individual variation decreased but behavioral predictability and stability were reduced in NL-F. Seven months after discontinuation of ENR we found no difference in plaque size and number, but ENR increased variance in hippocampal plaque counts in NL-F. A reactive increase in adult hippocampal neurogenesis in NL-F, known from other models, was normalized by ENR. Our data suggest that, while NL-F has early effects on individual behavioral patterns in response to ENR, there are lasting effects at the level of cellular plasticity even after discontinuation of ENR. Hence, early behavior matters for maintaining individual behavioral trajectories and brain plasticity even under maximally constraint conditions.

neuroscience↗

bioRxiv2022

Individual behavioral trajectories shape whole-brain connectivity in mice

It is widely assumed that our actions shape our brains and that the resulting connections determine who we are. To test this idea in a reductionist setting, in which genes and environment are controlled, we investigated differences in neuroanatomy and structural covariance by ex vivo structural magnetic resonance imaging (MRI) in mice whose behavioral activity was continuously tracked for 3 months in a large, enriched environment. We confirmed that environmental enrichment increases mouse hippocampal volumes. Stratifying the enriched group according to individual longitudinal behavioral trajectories, however, revealed striking differences in mouse brain structural covariance in continuously highly active mice compared to those whose trajectories showed signs of habituating activity. Network-based statistics identified distinct sub-networks of murine structural covariance underlying these differences in behavioral activity. Together, these results reveal that differentiated behavioral trajectories of mice in an enriched environment are associated with differences in brain connectivity.

neuroscience↗

bioRxiv2022

Rich Experience Boosts Functional Connectome and High-Dimensional Coding in Hippocampal Network

Challenging the brain with experiential richness creates tissue-level changes and synaptic plasticity, but the interjacent network level has not been accessible. We here show that environmental enrichment has unexpectedly far-reaching effects on network connectivity and multi-dimensional coding in the hippocampus. We present direct evidence that experience impacts local and global network connectivity, synchrony, and rhythmic dynamics. For this, we investigated the hippocampi from standard-housed mice (SD) and mice living in an enriched environment (ENR) using large-scale ex vivo recordings with a high-density microelectrode sensing array that - with the unprecedented spatiotemporal resolution-allowed simultaneous electrophysiological assessment across the entire circuit. In the absence of extrinsic electrical network stimulation, we found enhanced functional connectivity and high-dimensional coding in hippocampal-cortical networks of ENR mice. The mapped connectome illustrated a scale-free smallworld topology and an ENR-induced resilience to random failures. ENR enhanced large-scale spatiotemporal firing patterns, which facilitated efficient pattern separation and boosted the information encoded in the firing phases of slow oscillatory rhythms. Given that essentially all electrophysiological studies on network behaviors have been done on animals housed in stimulus-poor conditions, our SD mice showed the expected normal functionality. The literature consequently underestimates the extent of spontaneous network activity and connectivity under truly physiological conditions. Our results pave the way to unveil fundamental mechanisms of experience-dependent enhancement in the hippocampal network underlying high brain functions and provide markers for large-scale network remodeling and metaplasticity.

neuroscience↗

bioRxiv2021

Lifelong musical activity is associated with multi-domain cognitive and brain benefits in older adults

1AO_SCPLOWBSTRACTC_SCPLOWRegular musical activity as a highly-stimulating lifestyle activity is proposed to be protective against age-related cognitive decline and Alzheimers disease (AD). This study investigated associations between lifelong regular musical instrument playing, late-life cognitive abilities and brain morphology in older adults. We show that musical activity over the life course is associated with better global cognition, working memory, executive functions, language, and visuospatial abilities accounting for reserve proxies. Playing music is not significantly associated with gray matter volume in regions most affected by aging and AD. Selectively in the musically active participants, multi-domain cognitive abilities were enhanced with preserved gray matter volume in frontal and temporal regions. Our correlational findings suggest that playing a musical instrument may improve the recruitment of existing brain resources to facilitate late-life cognitive capacities. We propose that engaging in regular musical activity could serve as a low-threshold multimodal enrichment strategy that may promote cognitive resilience in advanced age.

neuroscience↗

bioRxiv2021

System genetics in the rat HXB/BXH family identifies Tti2 as a pleiotropic quantitative trait gene for adult hippocampal neurogenesis and serum glucose

Neurogenesis in the adult hippocampus contributes to learning and memory in the healthy brain but is dysregulated in metabolic and neurodegenerative diseases. The molecular relationships between neural stem cell activity, adult neurogenesis, and global metabolism are largely unknown. Here we applied unbiased systems genetic methods to quantify genetic covariation among adult neurogenesis and metabolic phenotypes in peripheral tissues of a genetically diverse family of rat strains, derived from a cross between the spontaneously hypertensive (SHR/OlaIpcv) strain and Brown Norway (BN-Lx/Cub). The HXB/BXH family is a very well established model to dissect genetic variants that modulate metabolic and cardiovascular disease and we have accumulated deep phenome and transcriptome data in a FAIR-compliant resource for systematic and integrative analyses. Here we measured rates of precursor cell proliferation, survival of new neurons, and gene expression in the hippocampus of the entire HXB/BXH family, including both parents. These data were combined with published metabolic phenotypes to detect a neurometabolic quantitative trait locus (QTL) for serum glucose and neuronal survival. We subsequently fine-mapped a key phenotype to a locus that includes the telo2-interacting protein 2 gene (Tti2)--a chaperone that modulates the activity and stability of PIKK kinases. To validate variants in or near Tti2 as a cause for differences in neurogenesis and glucose levels, we generated a targeted frameshift mutation on the SHR/OlaIpcv background. Heterozygous SHR-Tti2+/- mutants had lower rates of hippocampal neurogenesis and hallmarks of dysglycemia compared to wild-type littermates. Our findings highlight Tti2 as a causal genetic and molecular link between glucose metabolism and structural brain plasticity. In humans, more than 800 genomic variants are linked to TTI2 expression, seven of which have associations to protein and blood stem cell factor concentrations, blood pressure and frontotemporal dementia. Author summaryMetabolic and neurological disorders are often comorbid, suggesting that biological pathways which orchestrate peripheral homeostasis and the integrity of the nervous system intersect. The genetic architecture behind these relationships is still poorly described, in part because molecular processes in the human brain are very difficult to study. We thus used a rodent genetic reference population to investigate links between adult hippocampal neurogenesis-- a cellular plasticity mechanism important for learning flexibility--and metabolism. We measured adult neurogenesis in the family of 30 HXB/BXH rat recombinant inbred strains, who are characterised by stable differences in metabolism, behaviour, and gene expression levels. Because gene variants affecting distinct traits segregated into different members of the family, we discovered that previously published phenotypes correlated to adult neurogenesis due to shared genomic sequence. We found that expression levels of Tti2--a part of a specialised protein chaperone complex regulating stability of PIKK kinases--were concomitantly influencing adult neurogenesis and serum glucose levels. In human populations hundreds of genomic variants regulate TTI2 expression, potentially affecting brain function and glucose homeostasis.

neuroscience↗

bioRxiv2020

De novo DNA methylation controls neuronal maturation during adult hippocampal neurogenesis

Dynamic DNA methylation controls gene-regulatory networks underlying cell fate specification. How DNA methylation patterns change during adult hippocampal neurogenesis and their relevance for adult neural stem cell differentiation and related brain function has, however, remained unknown. Here, we show that neurogenesis-associated de novo DNA methylation is critical for maturation and functional integration of adult-born hippocampal neurons. Cell stage-specific bisulfite sequencing revealed a pronounced gain of DNA methylation at neuronal enhancers, gene bodies and binding sites of pro-neuronal transcription factors during adult neurogenesis, which mostly correlated with transcriptional up-regulation of the associated loci. Inducible deletion of both de novo DNA methyltransferases Dnmt3a and Dnmt3b in adult neural stem cells specifically impaired dendritic outgrowth and synaptogenesis of new-born neurons, resulting in reduced hippocampal excitability and specific deficits in hippocampus-dependent learning and memory. Our results highlight that, during adult neurogenesis, remodeling of neuronal methylomes is fundamental for proper hippocampal function.

neuroscience↗

bioRxiv2020

Adult-born neurons promote cognitive flexibility by improving memory precision and indexing

The dentate gyrus (DG) of the hippocampus is fundamental for cognitive flexibility and has the extraordinary ability to generate new neurons throughout life. Recent evidence suggested that adult-born neurons differentially modulate input to the DG during the processing of spatial information and novelty. However, how this differential regulation by neurogenesis is translated into different aspects contributing cognitive flexibility is unclear. Here, we increased adult-born neurons by a genetic expansion of neural stem cells and studied their influence during navigational learning. We found that increased neurogenesis improved memory precision, indexing and retention and that each of these gains was associated with a differential activation of specific DG compartments and better separation of memory representations in the DG-CA3 network. Our results highlight the role of adult-born neurons in promoting memory precision in the infrapyramidal and indexing in the suprapyramidal blade of the DG and together contributing to cognitive flexibility. One sentence summaryNeurogenesis improves memory precision and indexing.

neuroscience↗

bioRxiv2020

Apple peel and flesh contain pro-neurogenic compounds

As mammals evolved exposed to particular diets, naturally abundant compounds may have become part of the set of environmental co-determinants that shaped brain structure and function. Here we investigated whether bioactive factors found in apples directly affect hippocampal neural stem cells and promote neurogenesis in the adult mouse. Whereas the consumption of apple juice per se neither altered adult hippocampal neurogenesis nor improved learning and memory, we did find specific direct effects of apple-derived factors on neural stem cell survival and differentiation. Our results revealed that quercetin, the most abundant flavanol in apple peel, was anti-proliferative at high concentrations but acted pro-neurogenically at low concentrations. This was confirmed in vivo, with intraperitoneally-delivered quercetin promoting survival and neuronal differentiation, without affecting proliferation, likely via the PI3 kinase-Akt and Nrf2-Keap1 pathways, respectively. Using a bio-assay-guided fractionation approach with high-resolution collision induced dissociation mass spectroscopy, we also identified additional pro-neurogenic compounds in apple flesh that were not related to flavonoids. In particular, we found that 3,5-dihydroxybenzoic acid, a weak agonist to the lactate receptor, significantly increased both in vitro and in vivo neural precursor cell proliferation and neurogenesis. Altogether, this work shows that both flavonoids and 3,5-dihydroxybenzoic acid are pro-neurogenic, not only by activating precursor cell proliferation but also through promoting cell cycle exit, cellular survival, and neuronal differentiation.

neuroscience↗

bioRxiv2020

Rtrack: a software package for reproducible automated water maze analysis

Rtrack is an open-source software package for the analysis of spatial exploration data from behavioural tests such as the Morris water maze. The software provides an easy-to-use interface for data import, analysis and visualisation. A parameter-free machine learning model allows rapid and reproducible classification of spatial search strategies. We also propose a standard export format to enable cross-platform data sharing for the first time in the field.

animal behavior and cognition↗