Biology subjects

Beck, H.

Publications and source records attributed to Beck, H..

At least 19 recordsLinked to original sources

bioRxiv2026

Targeting epilepsy with photopharmacology in human brain tissue

Photo-activatable drugs (PDs) are rapidly emerging as precision therapeutics across biomedical research, yet their potential in epilepsy treatment has remained understudied. Given that 30% of epilepsies are medically refractory, and anti-seizure medications often cause multi-organ side-effects, PDs could break new ground. Here, we evaluate light-switchable ion-channel blockers QAQ and CQAQ, and a newly developed caged propofol (CaP), in murine brain slices, and postsurgical brain tissue from patients with epilepsy or brain tumors. In mice, we show that QAQ/CQAQ reversibly suppress neuronal firing, while photo-activated CaP prolonged inhibitory post-synaptic currents and enhanced leak current. While QAQ caused identical effects in human tissue, CQAQ unexpectedly increased firing. Activated CaP robustly suppressed epileptiform activity across species. This work establishes CaP as a tool for neuroscience and disease-related studies. Our results highlight the necessity for early human model testing in biomedical research, and showcase photopharmacology as a potential powerful approach to control human epilepsy.

pharmacology and toxicology↗

bioRxiv2025

Nanoscale dendritic shaft constrictions shape synaptic integration in fine caliber principal neuron dendrites

Traditionally, theoretical studies typically described dendritic morphology as optimized for efficient synaptic voltage transfer from spines to the soma, implemented as a tubular design respecting Ralls 3/2 rule for impedance matching at branch points. Here, we reveal that this view is an oversimplification. Using three high-resolution imaging techniques, we demonstrate that dendrites in cortical and hippocampal neurons contain nanoscale constrictions, comparable in diameter to spine necks. We provide theoretical and experimental evidence that these constrictions partition the dendrite into distinct electrical compartments, significantly shaping dendritic integration of synaptic potentials.

neuroscience↗

bioRxiv2025

Early postnatal CA3 hyperexcitability drives hippocampal development and epileptogenesis in SCN2A developmental and epileptic encephalopathy

Developmental and epileptic encephalopathies caused by pathogenic variants in SCN2A (SCN2A-DEE), encoding the voltage-gated sodium channel Nav1.2, present with early-life seizures, developmental delay, and increased mortality. Using a novel Scn2a p.A263V gain-of-function (GOF) mouse model, we demonstrate gene-dose and background-dependent phenotypes ranging from self-limited neonatal seizures to chronic epilepsy with high mortality. In vivo electrophysiology revealed hippocampal seizures as early as postnatal day 2.5, with CA3-driven gamma oscillations preceding seizure onset. CA3 and CA1 pyramidal neurons exhibited transient hyperexcitability during early postnatal development, resolving by P24-30. Single-cell RNA sequencing uncovered gene dose-dependent accelerated maturation of hippocampal networks, peaking at P7, alongside widespread transcriptional changes in excitatory and inhibitory neurons. In adulthood, persistent hippocampal network alterations emerged, marked by reduced mid-gamma oscillations and theta-gamma coupling. Our findings establish hippocampal CA3 hyperexcitability as an early driver of epileptogenesis in SCN2A-DEE and highlight it as a potential therapeutic target to mitigate disease progression.

neuroscience↗

bioRxiv2025

Transformations of the spatial activity manifold convey aversive information in CA3

Hippocampal circuits form cognitive maps representing spatial position and integrating contextual information, including affective cues, within episodic memory representations. We investigated how spatial and affective information combine in the population activity of CA3 axons by imaging intermediate-to-dorsal and dorsal-to-dorsal projections in mice navigating a linear track before, during, and after exposure to an aversive air puff stimulus. Our analyses reveal that both axonal populations maintain a robust, time-invariant spatial coding manifold across recordings, independent of affective context. Alterations to this common manifold encode the presence of the aversive stimulus without disrupting the spatial representation. Both axonal pathways encoded affective information with similar efficacy. This population-level encoding was distributed similarly across place and non-place cells. Our findings demonstrate that hippocampal CA3 axons integrate spatial and affective information within a common representational geometry while preserving the ability to extract each information type separately.

neuroscience↗

bioRxiv2024

Region-specific spreading depolarization drives aberrant post-ictal behavior

Confusion, aphasia, and unaware wandering are prominent post-ictal symptoms regularly observed in temporal lobe epilepsy (TLE)1. Despite the potentially life-threatening nature of the immediate post-ictal state2, its neurobiological underpinnings remain understudied3. We provide evidence in mice and humans that seizure-associated focal spreading depolarization (sSD) is a pathoclinical key factor in epilepsy. Using two-photon or widefield imaging (hippocampus, neocortex), field potential and single unit recordings, and behavioral assessment in mice, we first studied seizures during viral encephalitis, and subsequently established an optogenetic approach to dissociate hippocampal seizures and SD. We find region-specific occurrence of sSD that displays distinct spatial trajectories to preceding seizures, and show that seizure-related and isolated hippocampal SD prompt post-ictal wandering. This clinically relevant locomotor phenotype occurred in the absence of hippocampal SD progression to the neocortex. Finally, we confirm sSD existence in human epilepsy, in a patient cohort with refractory focal epilepsy, via Behnke-Fried electrode recordings. In this cohort, sSD displayed a similar temporomesial propensity as in mice. This work uncovers sSD as a previously underrecognized pathoclinical entity underlying postictal behavioral abnormalities in epilepsy. Our results carry wide-reaching ramifications for epilepsy research and neurology, and challenge current EEG-standards.

neuroscience↗

bioRxiv2024

CACHE Challenge #1: targeting the WDR domain of LRRK2, a Parkinson's Disease associated protein.

The CACHE challenges are a series of prospective benchmarking exercises meant to evaluate progress in the field of computational hit-finding. Here we report the results of the inaugural CACHE #1 challenge in which 23 computational teams each selected up to 100 commercially available compounds that they predicted would bind to the WDR domain of the Parkinsons disease target LRRK2, a domain with no known ligand and only an apo structure in the PDB. The lack of known binding data and presumably low druggability of the target is a challenge to computational hit finding methods. Seventy-three of the 1955 procured molecules bound LRRK2 in an SPR assay with KD lower than 150 M and were advanced to a hit expansion phase where computational teams each selected up to 50 analogs each. Binding was observed in two orthogonal assays with affinities ranging from 18 to 140 M for seven chemically diverse series. The seven successful computational workflows varied in their screening strategies and techniques. Three used molecular dynamics to produce a conformational ensemble of the targeted site, three included a fragment docking step, three implemented a generative design strategy and five used one or more deep learning steps. CACHE #1 reflects a highly exploratory phase in computational drug design where participants sometimes adopted strikingly diverging screening strategies. Machine-learning accelerated methods achieved similar results to brute force (e.g. exhaustive) docking. First-in-class, experimentally confirmed compounds were rare and weakly potent, indicating that recent advances are not sufficient to effectively address challenging targets.

biochemistry↗

bioRxiv2024

A probabilistic view of forbidden links: their prevalence and their consequences for the robustness of mutualistic networks

The presence in ecological communities of unfeasible species interactions, termed forbidden links, due to physiological or morphological exploitation barriers has been long debated, but little direct evidence has been found. Forbidden links are likely to make ecological communities less robust to species extinctions, stressing the need to assess their prevalence. Here, we used a dataset of plant-hummingbird interactions, coupled with a Bayesian hierarchical model, to assess the importance of exploitation barriers in determining species interactions. We found evidence for exploitation barriers between flowers and hummingbirds across the 32 studied communities, however, the proportion of forbidden links changed drastically among communities, because of changes in trait distributions. The higher the proportion of forbidden links, the more they decreased network robustness, because of constraints on interaction rewiring. Our results suggest that exploitation barriers are not rare in plant-hummingbird communities and have the potential to limit the rescue of species experiencing partner extinction.

ecology↗

bioRxiv2023

Aberrant hippocampal Ca2+ micro-waves following synapsin-dependent adenoviral expression of Ca2+ indicators

Genetically encoded calcium indicators (GECIs) such as GCaMP are invaluable tools in neuroscience to monitor neuronal activity using optical imaging. The viral transduction of GECIs is commonly used to target expression to specific brain regions, can be conveniently used with any mouse strain of interest without the need for prior crossing with a GECI mouse line and avoids potential hazards due to the chronic expression of GECIs during development. A key requirement for monitoring neuronal activity with an indicator is that the indicator itself minimally affects activity. Here, using common adeno-associated viral (AAV) transduction procedures, we describe spatially confined aberrant Ca2+ micro-waves slowly travelling through the hippocampus following expression of GCaMP6, GCaMP7 or R-CaMP1.07 driven by the synapsin promoter with AAV-dependent gene transfer, in a titre-dependent fashion. Ca2+ micro-waves developed in hippocampal CA1 and CA3, but not dentate gyrus (DG) nor neocortex, were typically first observed at 4 weeks after viral transduction, and persisted up to at least 8 weeks. The phenomenon was robust, observed across laboratories with various experimenters and setups. Our results indicate that aberrant hippocampal Ca2+ micro-waves depend on the promoter and viral titre of the GECI, density of expression as well as the targeted brain region. We used an alternative viral transduction method of GCaMP which avoids this artifact. The results show that commonly used Ca2+-indicator AAV transduction procedures can produce artefactual Ca2+ responses. Our aim is to raise awareness in the field of these artefactual transduction-induced Ca2+ micro-waves and we provide a potential solution. Impact statement: Common AAV transduction procedures induce artefactual spatially confined Ca2+ waves in the hippocampus.

neuroscience↗

bioRxiv2023

replicAnt - generating annotated images of animals in complex environments with Unreal Engine

Deep learning-based computer vision methods are transforming animal behavioural research. Transfer learning has enabled work in non-model species, but still requires hand-annotation of example footage, and is only performant in well-defined conditions. To overcome these limitations, here we present replicAnt, a configurable pipeline implemented in Unreal Engine 5 and Python, designed to generate large and variable training datasets on consumer-grade hardware. replicAnt places 3D animal models into complex, procedurally generated environments, from which automatically annotated images can be exported. We demonstrate that synthetic data generated with replicAnt can significantly reduce the hand-annotation required to achieve benchmark performance in common applications such as animal detection, tracking, pose-estimation, and semantic segmentation. We also show that it increases the subject-specificity and domain-invariance of the trained networks, thereby conferring robustness. In some applications, replicAnt may even remove the need for hand-annotation altogether. It thus represents a significant step towards porting deep learning-based computer vision tools to the field.

animal behavior and cognition↗

bioRxiv2023

High-throughput single molecule tracking identifies drug interactions and cellular mechanisms

The regulation of cell physiology depends largely upon interactions of functionally distinct proteins and cellular components. These interactions may be transient or long-lived, but often affect protein motion. Measurement of protein dynamics within a cellular environment, particularly while perturbing protein function with small molecules, may enable dissection of key interactions and facilitate drug discovery; however, current approaches are limited by throughput with respect to data acquisition and analysis. As a result, studies using super-resolution imaging are typically drawing conclusions from tens of cells and a few experimental conditions tested. We addressed these limitations by developing a high-throughput single-molecule tracking (htSMT) platform for pharmacologic dissection of protein dynamics in living cells at an unprecedented scale (capable of imaging > 106 cells/day and screening > 104 compounds). We applied htSMT to measure the cellular dynamics of fluorescently tagged estrogen receptor (ER) and screened a diverse library to identify small molecules that perturbed ER function in real time. With this one experimental modality, we determined the potency, pathway selectivity, target engagement, and mechanism of action for identified hits. Kinetic htSMT experiments were capable of distinguishing between on-target and on-pathway modulators of ER signaling. Integrated pathway analysis recapitulated the network of known ER interaction partners and suggested potentially novel, kinase-mediated regulatory mechanisms. The sensitivity of htSMT revealed a new correlation between ER dynamics and the ability of ER antagonists to suppress cancer cell growth. Therefore, measuring protein motion at scale is a powerful method to investigate dynamic interactions among proteins and may facilitate the identification and characterization of novel therapeutics.

cell biology↗

bioRxiv2021

An astrocytic signaling loop for frequency-dependent control of dendritic integration and spatial learning

Dendrites of hippocampal CA1 pyramidal cells amplify clustered glutamatergic input by activation of voltage-gated sodium channels and N-methyl-D-aspartate receptors (NMDARs). NMDAR activity depends on the presence of NMDAR co-agonists such as D-serine, but how co-agonists influence dendritic integration is not well understood. Using combinations of whole-cell patch clamp, iontophoretic glutamate application, two-photon excitation fluorescence microscopy and glutamate uncaging we found that exogenous D-serine reduces the threshold of dendritic spikes and increases their amplitude. Triggering an astrocytic mechanism controlling endogenous D-serine supply via endocannabinoid receptors (CBRs) also increased dendritic spiking. Unexpectedly, this pathway was activated by pyramidal cell activity primarily in the theta range, which required HCN channels and astrocytic CB1Rs. Therefore, astrocytes close a positive and frequency-dependent feedback loop between pyramidal cell activity and their integration of dendritic input. Its disruption led to an impairment of spatial memory, which demonstrates its behavioral relevance.

neuroscience↗

bioRxiv2021

A novel theoretical framework for simultaneous measurement of excitatory and inhibitory conductances

Firing of neurons throughout the brain is determined by the precise relations between excitatory and inhibitory inputs and disruption of their balance underlies many psychiatric diseases. Whether or not these inputs covary over time or between repeated stimuli remains unclear due to the lack of experimental methods for measuring both inputs simultaneously. We developed a new analytical framework for instantaneous and simultaneous measurements of both the excitatory and inhibitory neuronal inputs during a single trial under current clamp recording. This can be achieved by injecting a current composed of two high frequency sinusoidal components followed by analytical extraction of the conductances. We demonstrate the ability of this method to measure both inputs in a single trial under realistic recording constraints and from morphologically realistic CA1 pyramidal model cells. Experimental implementation of our new method will facilitate the understanding of fundamental questions about the health and disease of the nervous system. ClassificationSystem Neuroscience, Cellular and Molecular Neuroscience

neuroscience↗

bioRxiv2020

Mysterious disappearances of a large mammal in Neotropical forests

The drivers of periodic population cycling by some animal species in northern systems remain unresolved1. Mysterious disappearances of populations of the Neotropical, herdforming white-lipped peccary (Tayassu pecari, henceforth "WLP") have been anecdotally documented and explained as local events resulting from migratory movements or overhunting2,3,4, or as disease outbreaks5,6, and have not been considered in the context of large-scale species-specific population dynamics. Here we present evidence that WLP disappearances represent troughs in population cycles that occur with regular periodicity and are synchronized at regional and perhaps continent-wide spatial scales. Analysis of 43 disappearance events and 88 years of commercial and subsistence harvesting data reveals boom - bust population cycles lasting from 20 to 30 years, in which a rapid population crash occurring over 1 to 5 years is followed by a period of absence of 7 to12 years and then a slow growth phase. Overhunting alone cannot explain the crashes, but as in northern systems dispersal during the growth phase appears to play a key role. This is the first documentation of population cycling in a tropical vertebrate.

ecology↗

bioRxiv2020

Ste20-like kinase is critical for inhibitory synapse maintenance and its deficiency confers a developmental dendritopathy

The size and structure of the dendritic arbor play important roles in determining how synaptic inputs of neurons are converted to action potential output. The regulatory mechanisms governing the development of dendrites, however, are insufficiently understood. The evolutionary conserved Ste20/Hippo kinase pathway has been proposed to play an important role in regulating the formation and maintenance of dendritic architecture. A key element of this pathway, Ste20-like kinase (SLK), regulates cytoskeletal dynamics in non-neuronal cells and is strongly expressed throughout neuronal development. However, its function in neurons is unknown. We show that during development of mouse cortical neurons, SLK has a surprisingly specific role for proper elaboration of higher, [≥] 3rd, order dendrites. Moreover, we demonstrate that SLK is required to maintain excitation-inhibition balance. Specifically, SLK knockdown caused a selective loss of inhibitory synapses and functional inhibition after postnatal day 15, while excitatory neurotransmission was unaffected. Finally, we show that this mechanism may be relevant for human disease, as dysmorphic neurons within human cortical malformations revealed significant loss of SLK expression. Overall, the present data identify SLK as a key regulator of both dendritic complexity during development and of inhibitory synapse maintenance.

neuroscience↗

bioRxiv2020

Targeting aberrant dendritic integration to treat cognitive comorbidities of epilepsy

Memory deficits are a debilitating symptom of epilepsy, but little is known about mechanisms underlying cognitive deficits. Here, we describe a Na+ channel-dependent mechanism underlying altered hippocampal dendritic integration, degraded place coding, and deficits in spatial memory. Two-photon glutamate uncaging experiments revealed that the mechanisms constraining the generation of Na+ spikes in hippocampal 1st order pyramidal cell dendrites are profoundly degraded in experimental epilepsy. A selective Nav1.3 sodium channel blocker reversed this effect, and Nav1.3 channels were up-regulated selectively in principal neurons at the mRNA level. Finally, in-vivo two-photon imaging revealed that the Nav1.3 channel blocker improves degraded hippocampal spatial representations, and reverses hippocampal memory deficits. Thus, a dendritic channelopathy may underlie cognitive deficits in epilepsy and targeting it pharmacologically may constitute a new avenue to enhance cognition. One Sentence SummaryImpaired input computations via aberrant dendritic spikes in chronic epilepsy degrade neuronal place codes and spatial memory

neuroscience↗

bioRxiv2020

Localized Chemogenetic Silencing of Inhibitory Neurons: A novel Mouse Model of Focal Cortical Seizures

Focal cortical epilepsies are frequently refractory to available anticonvulsant drug therapies. One key factor contributing to this state is the limited availability of animal models that allow to reliably study focal cortical seizures and how they recruit surrounding brain areas in-vivo. In this study, we selectively expressed the inhibitory chemogenetic receptor, hM4D, in GABAergic neurons in focal cortical areas using viral gene transfer. Following focal silencing of GABAergic neurons by administration of Clozapine-N-Oxide (CNO), we demonstrated reliable induction of local epileptiform events in the electroencephalogram (EEG) signal of awake freely moving mice. Experiments in anesthetized mice showed consistent induction of focal seizures in two different brain regions - the barrel cortex (BC) and at the medial prefrontal cortex (mPFC). Seizures were accompanied by high frequency oscillations, a known characteristic of human focal seizures. Seizures propagated, but an analysis of seizure propagation revealed favored propagation pathways. CNO-induced epileptiform events propagated from the BC on one hemisphere to its counterpart and from the BC to the mPFC, but not vice-versa. Lastly, post-CNO epileptiform events in the BC could be triggered by sensory whisker-pad stimulation, indicating that this model, applied to sensory cortices, may be useful to study sensory-evoked seizures. Taken together, our results show that targeted chemogenetic inhibition of GABAergic neurons using hM4D can serve as a novel, versatile and reliable model of focal cortical epilepsy suitable to systematically study cortical ictogenesis in different cortical areas. Significance StatementFocal cortical epilepsies are often hard to alleviate using current anticonvulsant therapies while further drug discovery is impeded by the limited variety of suitable animal models. In this study, we established a novel model of focal cortical seizures induced by spatially-restricted chemogenetic silencing of cortical inhibitory neurons. We have shown this method to be effective at various cortical regions and reliably induce seizures that share key characteristics with known human epilepsy traits, including sensory triggering and seizure propagation. This model may thus be used to advance the discovery of new remedies for focal cortical epilepsies, as well as to improve our understanding of seizure spread along different cortical pathways.

neuroscience↗

bioRxiv2020

Extratubular polymerized uromodulin induces leukocyte recruitment and inflammation in vivo

Uromodulin (UMOD) is produced and secreted by tubular epithelial cells. Secreted UMOD polymerizes (pUMOD) within the lumen, where it regulates salt transport and protects the kidney from bacteria and stone formation. Under various pathological conditions, pUMOD accumulates within the tubular lumen and reaches extratubular sites where it may interact with renal interstitial cells. Here, we investigated the potential of extratubular pUMOD to act as a damage associated molecular pattern (DAMP) molecule thereby creating local inflammation. We found that intrascrotal and intraperitoneal injection of pUMOD induced leukocyte recruitment in vivo and led to TNF- secretion by F4/80 positive macrophages. Additionally, pUMOD directly affected vascular permeability and increased neutrophil extravasation independent of macrophage-released TNF-. Interestingly, pUMOD did not directly upregulate adhesion molecules on endothelial cells and did not directly activate {beta}2 integrins on neutrophils. In obstructed neonatal murine kidneys, we observed extratubular UMOD accumulation with tubular atrophy and leukocyte infiltrates. Finally, we found extratubular UMOD deposits associated with peritubular leukocyte infiltration in kidneys from patients with inflammatory kidney diseases. Taken together, we identified extratubular pUMOD as a strong inducer of leukocyte recruitment, underlining its critical role in mounting an inflammatory response in various kidneys pathologies.

immunology↗

bioRxiv2020

Dentate gyrus population activity during immobility drives formation of precise memories

The hippocampal dentate gyrus is an important relay conveying sensory information from the entorhinal cortex to the hippocampus proper. During exploration, the dentate gyrus has been proposed to act as a pattern separator. However, the dentate gyrus also shows structured activity during immobility and sleep. The properties of these activity patterns at cellular resolution, and their role in hippocampal-dependent memory processes have remained unclear. Using dual-color in-vivo two-photon Ca2+ imaging, we show that in immobile mice dentate granule cells generate sparse, synchronized activity patterns associated with entorhinal cortex activation. These population events are structured and modified by changes in the environment; and they incorporate place- and speed cells. Importantly, they recapitulate population patterns evoked during self-motion. Using optogenetic inhibition during immobility, we show that granule cell activity during immobility is required to form dentate gyrus-dependent spatial memories. These data suggest that memory formation is supported by dentate gyrus replay of population codes of the current environment.

neuroscience↗