Biology subjects

Braun, C.

Publications and source records attributed to Braun, C..

At least 19 recordsLinked to original sources

bioRxiv2026

Shaping cryogenic 3D volume imaging by pFIB ion species and milling voltage

Cryogenic plasma focused ion beam-scanning electron microscopy (cryo-pFIB-SEM) enables nanoscale volume imaging of vitrified cells and tissues, but the fidelity of each newly exposed block-face depends on how ions interact with compositionally heterogeneous biological material. Using xenon, argon, oxygen, and nitrogen plasma beams across a 30-2 kV voltage range, we examined how ion species and accelerating voltage influence block-face quality and ultrastructural fidelity. Curtaining imposed a species-dependent lower limit on accelerating voltage, with xenon and argon supporting uniform milling to 10 kV and oxygen and nitrogen to 15 kV. Monte Carlo simulations predicted substantially reduced ion penetration and atomic displacement under these species-specific low-kV conditions. Experimentally, lowering milling voltage suppressed charging and topographic artifacts, with the largest effects observed at heterogeneous interfaces. Oxygen and nitrogen produced greater membrane sharpness and organelle contrast than the noble gases, and these differences influenced machine-learning-based recognition of fine organelle features in 3D datasets. Together, these findings show that cryo-pFIB-SEM image quality cannot be optimized by accelerating voltage or ion species independently. Instead, milling performance reflects a tradeoff among surface fidelity, charging, contrast, and curtaining that depends on local specimen composition. Species-specific low-kV milling therefore provides a practical framework for matching cryo-pFIB-SEM acquisition conditions to the structural and biophysical properties of the biological target.

cell biology↗

bioRxiv2026

A cell type-resolved proteomic atlas of the human body

Proteins define what cells do, yet their systematic quantification across human cell types has remained out of reach. Using Deep Visual Proteomics on tissue from a healthy female donor, we built an atlas of 27 cell types across 14 tissues, quantifying two-thirds of all human protein-coding genes, with up to 8,500 per population. The proteome partitions bimodally into a universal core and highly specialized programs. Integration into the Human Protein Atlas Single Cell Resource enabled comparison of RNA and protein abundance at cell type resolution, revealing that concordance depends on pathway rather than cellular identity. This resolution uncovered cancer-testis antigens in oocytes invisible to bulk profiling. Our openly accessible resource provides a foundation for cell type-resolved proteomics in health and disease.

biochemistry↗

bioRxiv2026

Extended high frequency hearing influences cortical response amplitudes to speech

Since young adults hear sounds up to 20 kHz, the loss of extended high-frequency hearing (EHF; above 8 kHz) is a hallmark of age-related hearing loss, often progressing from early lifetime. However, this deficit frequently goes undetected because routine clinical hearing tests and most hearing aids are currently limited mostly up to 8 kHz. EHF hearing has been linked to deficits in speech perception in noise and to self-reported hearing. However, it remains elusive how EHF hearing influences speech intelligibility. Here we recorded neuromagnetic brain responses using magnetoencephalography (MEG) within a frequency-tagging speech paradigm designed to probe hierarchical levels of attention and memory-dependent speech processing and recognition. Auditory evoked cortical magnetic field (AEF) responses were significantly reduced in both left and right brain hemispheres in individuals with impaired EHF hearing compared to those subjects with rather preserved EHF hearing. A gradual reinforcement of left-hemispheric AEF seen over age was not observed in young adults (19-29 y) with preserved EHF hearing. This was linked to stronger auditory brainstem responses (ABR), reflecting better neural synchronized auditory responses at stimulus onset. The reinforced left hemispheric dominance in young adults with impaired EHF hearing, in contrast, was linked to lower ABRs. Our findings suggest that sound energy above 8 kHz contributes through its impact on stimulus-onset synchrony to phase locking of oscillations in the auditory cortex to intelligible speech. Together, the results highlight the need to reconsider the neglect of EHF hearing in both audiological assessment and hearing aid design. SignificanceWe show here that deficits in extended high-frequency (EHF) hearing, up to now neglected in routine clinical audiometry and hearing aid technology, lead to reduced cortical evoked auditory field (AEF) response amplitudes to attended and unattended speech, even at a young age. A gradual increase in reinforced left-hemispheric AEF responses during attended speech does not occur in young people with good EHF hearing; this is linked to better synchronization of neural responses at the onset of sound. This suggests a crucial role of sounds containing energy above 8kHz in minimizing the need for cognitive resources during active listening. Collectively, our results challenge current clinical practices and underscore the need to incorporate EHF hearing into audiological assessment and hearing aid design.

neuroscience↗

bioRxiv2026

Phenotypic screening for small molecules that lower PrP in cultured cells

PrP lowering is a validated therapeutic hypothesis in prion disease. To identify small molecules that reduce PrP levels, we performed phenotypic screening in cultured cells. To prioritize PrP specificity in our primary screen, we generated mouse N2a cells stably expressing GFP and used high content imaging analysis to select compounds that lowered PrP without affecting GFP signal or cell viability. Screening a curated library of 3,492 compounds with annotated mechanisms of action identified two small molecules, EYH (PubChem CID: 71678945) and LCZ (PubChem CID: 24970350), that selectively and dose-dependently lowered PrP. Proteomics on whole cell lysates identified PrP as the #1 or #2 most potently downregulated out of 8,722 proteins detected. Both compounds minimally affected Prnp mRNA, reduced expression of exogenously transfected PrP, and remained potent in non-dividing primary cells, consistent with a post-translational mechanism. Co-treatment with the proteasome inhibitor MG132 yielded accumulation of unglycosylated PrP, demonstrating proteasome clearance of PrP. However, both compounds showed limited or no activity in human cell lines, and failed to reduce PrP in vivo after 14 days of treatment. These findings highlight the challenges associated with mechanism-agnostic phenotypic screening for PrP-lowering compounds and support prioritizing compounds with known mechanisms of action.

neuroscience↗

bioRxiv2025

Fixel-Based Analysis reveals microstructural visual pathway changes associated with retinal remodeling in retinitis pigmentosa

Retinitis pigmentosa (RP) is the most common inherited retinal dystrophy, traditionally considered a photoreceptor degenerative disorder. However, the relationship between retinal degeneration and structural alterations along central visual pathways remains poorly understood. We investigated possible structural links across the retinocortical pathway in 15 genetically characterized RP patients (RHO, PDE6A, PDE6B mutations) compared with 22 healthy controls, using spectral-domain optical coherence tomography (SD-OCT) combined with diffusion-weighted MRI and fixel-based analysis (FBA). Retinal segmentation revealed marked outer layer thinning (outer nuclear layer: -55% foveal, -77% parafoveal) with significant inner layer thickening at the fovea (inner plexiform layer +29%, inner nuclear layer +40%). Parafoveal regions showed near-complete photoreceptor loss but inner retinal thickness approaching normal values. FBA demonstrated significant fiber density reductions in optic tracts and optic radiations, without corresponding macrostructural changes in tract cross-section, suggesting early microstructural disruption preceding atrophy. Correlation analyses revealed significant associations between parafoveal inner plexiform layer thickness and fiber density in both optic tracts (r=0.856) and radiations (r=0.768), with no correlations observed at the foveal level. These findings demonstrate complex, region-specific retinal remodeling in RP, likely reflecting Muller cell gliosis rather than mechanical compensation. The fiber density reduction without tract atrophy suggests trans-synaptic degeneration along visual pathways. This multimodal framework provides insights into structural propagation in inherited retinal dystrophies and may serve as a biomarker for evaluating therapeutic interventions aimed at photoreceptor restoration.

neuroscience↗

bioRxiv2025

Robust spatial hearing beyond primary interaural cues in humans over deep neural networks

Spatial hearing allows humans to localize sound sources in the azimuth plane using interaural time (ITD) and level (ILD) differences, but the contribution of additional auditory features remains unclear. To investigate this, we measured human localization performance with natural and artificial stimuli that selectively included or excluded ITD and ILD as primary interaural cues. As expected, human listeners relied synergistically on ITD and ILD for accurate azimuth localization. Moreover, even when both primary cues were absent, localization performance remained above chance level. We compared human performance with state-of-the-art deep neural networks (DNN) optimized for sound localization to investigate possible computational mechanisms underlying this robust performance. In contrast to humans, DNNs demonstrated high accuracy only for stimuli that resembled their training regime but failed when primary interaural cues were absent. This human-DNN misalignment highlights a fundamental distinction in sensory processing strategies, potentially arising from the simplicity bias inherent in DNN training, with human reliance on a wider range of auditory features likely reflecting evolutionary pressures favoring adaptability across diverse acoustic environments. Together, our results demonstrate the robustness of human spatial hearing beyond primary interaural cues and point to promising directions for advancing artificial systems and informing clinical applications, such as cochlear implants and auditory prosthetics.

animal behavior and cognition↗

bioRxiv2025

Frontocentral brain networks amplify action-oriented temporal prediction errors

Successful sensorimotor behavior depends on anticipating when a tactile event will occur and translating it into rapid action, yet it remains unclear how action requirements shape temporal prediction in the human cortex. Here, we combined Magnetoencephalography (MEG), multivariate decoding and computational modeling to contrast temporally jittered finger stimulations under passive versus action-oriented conditions. We characterized a distributed frontal sensorimotor network that was linked to fast tactile-motor associations and predicted reaction-time variability. We found that trial-by-trial deviations from expected stimulus timing modulated behavior, with stronger frontocentral prediction-error encoding when an overt response was required. Temporal prediction errors were primarily encoded in a motor rather than sensory reference frame. These results reveal that action demands dynamically amplify temporal error signaling in sensorimotor circuits, in line with predictive coding frameworks postulating that the brain preferentially encodes task-relevant and goal-directed sensory prediction errors.

neuroscience↗

bioRxiv2025

FAIMS-GPF XL-MS: crosslinking-mass spectrometry based on gas-phase fractionation

Protein-protein interactions (PPIs) underpin nearly all cellular processes; therefore, mapping PPI and protein-protein association networks is critical for understanding how biological systems function in health and disease. However, many functionally relevant PPIs are transient and mediated by weak affinity interactions, making them challenging to detect. Using chemical cross-linking together with mass spectrometry (XL-MS) has emerged as an important category of methods for mapping PPIs, including those that are more dynamic and transient, although XL-MS workflows face limitations which hinder their routine use, especially in proteomic platforms. Here, to address these limitations, we developed a XL-MS workflow based on gas-phase fractionation (GPF) using high-field asymmetric waveform ion mobility spectrometry (FAIMS). Our optimized FAIMS-GPF XL-MS protocols exhibited improved performance when handling both low-complexity samples, such as purified Cdk7-Activating Kinase (CAK) heterotrimer, and high-complexity cross-linked HeLa lysates. In HeLa lysate, we identified 1,278 cross-links accounting for 213 PPIs without any in-solution fractionation, starting from less than 20 {micro}g of sample. The method also proved effective for analyzing low-abundance, high-complexity samples such as spliceosomes. Overall, FAIMS-GPF enhanced the detection of cross-linked peptides and improved PPI coverage, thus offering a scalable, high-sensitivity solution for XL-MS integration with structural biology and functional proteomics applications.

systems biology↗

bioRxiv2025

Neural signatures of predictive coding underlying the acquisition of incidental sensory associations

A longstanding question in cognitive science is whether the human brain learns sensory regularities that are irrelevant to ongoing behavior, a phenomenon known as incidental associative learning. Here, we provide evidence at the single subject level that humans indeed acquired such incidental associations and reveal their neural signatures by combining Electroencephalography (EEG), multivariate decoding and computational modeling. We found robust encoding of incidental predictions and prediction errors underlying associative learning, consistent with predictive coding theories. Prediction errors were modulated by epistemic uncertainty, incidental associations persisted in memory over days and generalized beyond stimulus-stimulus pairings to encompass broader sensory events, including the absence of stimulation. Together, our results challenge traditional assumptions that associative learning requires behavioral relevance or physical co-occurrence and point to uncertainty minimization about environmental state transitions as a general objective of brain function. This intrinsic drive may reflect a fundamental computational principle supporting the formation of internal predictive models that guide perception, learning, and adaptive behavior.

neuroscience↗

bioRxiv2024

PrP turnover in vivo and the time to effect of prion disease therapeutics

PrP lowering is effective against prion disease in animal models and is being tested clinically. Therapies in the current pipeline lower PrP production, leaving pre-existing PrP to be cleared according to its own half-life. We hypothesized that PrPs half-life may be a rate-limiting factor for the time to effect of PrP-lowering drugs, and one reason why late treatment of prion-infected mice is not as effective as early treatment. Using isotopically labeled diet with targeted mass spectrometry, as well as antisense oligonucleotide treatment followed by timed PrP measurement, we estimate a half-life of 5-6 days for PrP in the brain. PrP turnover is not affected by over-or under-expression. Mouse PrP and human PrP have similar turnover rates measured in wild-type or humanized knock-in mice. CSF PrP appears to mirror brain PrP in real time in rats. PrP in the colon is readily quantifiable and has a half-life just slightly shorter than in brain. An under-expressed pathogenic mutant PrP, corresponding to D178N in humans, exhibits an accelerated turnover rate. Our data may inform the design of both preclinical and clinical studies of PrP-lowering drugs. Author SummaryPrion disease is a fatal brain disease caused by misfolding of the prion protein (PrP). Emerging therapies for prion disease seek to reduce the amount of PrP produced in the brain in order to delay onset of disease or slow progression. Mouse studies have shown that if these therapies are initiated too late, their benefit is limited or they may not help at all. Here we measure the half-life of PrP in the mouse brain, and find that it is about 5 days. When drugs are used to lower PrP by cutting up the RNA that encodes PrP, the RNA drops rapidly while the protein lags behind, and does not reach its minimum level until 4 weeks after the drug is dosed. This half-life is about the same regardless of the species of PrP (mouse or human) and whether or not the brain is infected with prions. Cerebrospinal fluid appears to reflect the real-time levels of brain PrP with no appreciable lag. PrP can be measured in colon, which may be useful in animal studies of systemic drugs to lower PrP. PrP turns over more quickly in the presence of a pathogenic genetic variant, the equivalent of the human D178N variant. These findings suggest that clinical trials can monitor PrP in cerebrospinal fluid to look at drug activity, but should plan timepoints far enough post-dose to account for PrPs rate of turnover, and should focus on patients who will survive long enough to benefit from the drug.

neuroscience↗

bioRxiv2024

Confirmation of Highly Pathogenic Avian Influenza (HPAI) H5N1 Associated with an Unexpected Mortality Event in South Polar Skuas (Stercorarius maccormicki) during 2023-2024 Surveillance Activities in Antarctica

From December 2023 to March 2024, a surveillance program to detect HPAI H5N1 was performed on Antarctica Territory, at Fildes Peninsula (King George Island, Maritime Antarctic), and James Ross Island. At Fildes Peninsula, samples from marine birds and mammals from four sampling locations were collected, based on their accessibility and the presence of animal colonies: Ardley Island, which presents a high concentration of Gentoo penguins (Pygoscelis papua); Ardley Cove were small groups of likely non-reproductive Chinstrap penguins (Pygoscelis antarcticus); Southern elephant (Mirounga leonina) and Weddell (Leptonycotes wedellii) seals haul-out sites; and, a nesting site of Southern giant petrels (Macronectes giganteus). On February 28th the surveillance group received a request for sample collection, due to the observation of deceased seabirds at James Ross Island in the area neighboring the Lachman lakes (63.7989 S, 57.8105 W). Six samples from five dead South polar skuas (Stercorarius maccormicki) were collected on March 3rd, 2024. All samples were collected adhering to the Antarctic Treaty guidelines. After collecting a total of 943 samples from Fildes Peninsula all results tested negative, and no individuals had clinical signs or behaviors compatible with HPAI. However, all samples from South polar skuas from James Ross Island were confirmed positive for HPAI H5N1 clade 2.3.4.4 by specific real-time RT-PCR reactions. These results confirmed the first mortality event registered in Antarctica (south of 60{degrees}S) caused by HPAI H5N1, in this case on South polar skuas. Further studies are needed to genetically characterize the virus and to better understand the role of skuas in the dynamics of viral dissemination in Antarctica.

microbiology↗

bioRxiv2024

Neural dynamics of semantic control underlying generative storytelling

Storytelling has been pivotal for the transmission of knowledge and cultural norms across human history. A crucial process underlying the generation of narratives is the exertion of cognitive control on the semantic representations stored in memory, a phenomenon referred as semantic control. Despite the extensive literature investigating the neural mechanisms of semantic control in generative language tasks, little effort has been done towards storytelling under naturalistic conditions. Here, we probed human participants to generate stories in response to a set of instructions which triggered a narrative that was either appropriate (ordinary), novel (random), or balanced (creative), while recording functional magnetic resonance imaging (fMRI) signal. By leveraging deep language models, we demonstrated how participants ideally balanced the level of semantic control during story generation. At the neural level, creative stories were differentiated by a multivariate pattern of neural activity in frontal cortices compared to ordinary ones and in fronto-temporo-parietal cortices with respect to randomly generated stories. Crucially, similar brain regions were also encoding the features that distinguished the stories behaviourally. Moreover, we decomposed the neural dynamics into connectome harmonic modes and found specific spatial frequency patterns underlying the modulation of semantic control during story generation. Finally, we found different functional coupling within and between the default mode, salience and control networks when contrasting creative stories with their controls. Together, our findings highlight the neural mechanisms underlying the regulation of semantic exploration during narrative ideation and contribute to a deeper understanding of the neural dynamics underpinning the role of semantic control in generative storytelling.

neuroscience↗

bioRxiv2024

Statistical learning of incidental perceptual regularities induces sensory conditioned cortical responses

Statistical learning of sensory patterns can lead to predictive neural processes enhancing stimulus perception and enabling fast deviancy detection. Predictive processes have been extensively demonstrated when environmental statistical regularities are relevant to task execution. Preliminary evidence indicates that statistical learning can even occur independently of task relevance and top-down attention, although the temporal profile and neural mechanisms underlying sensory predictions and error signals induced by statistical learning of incidental sensory regularities remain unclear. In our study, we adopted an implicit sensory conditioning paradigm that elicited the generation of specific perceptual priors in relation to task-irrelevant audio-visual associations, while recording Electroencephalography (EEG). Our results showed that learning of non-relevant but statistically interrelated neutral audio-visual stimuli resulted in early neural responses to predictive auditory stimuli conveying anticipatory signals of expected visual stimulus presence or absence, and in specific modulation of cortical responses to probabilistic visual stimulus presentation or omission. Pattern similarity analysis indicated that predictive auditory stimuli tended to resemble the response to expected visual stimulus presence or absence. Remarkably, Hierarchical Gaussian filter modeling estimating dynamic changes of prediction error signals in relation to differential probabilistic occurrences of audio-visual stimuli further demonstrated instantiation of predictive neural signals by showing distinct neural processing of prediction error in relation to violation of expected visual stimulus presence or absence. Overall, our findings indicated that statistical learning of non-salient and task-irrelevant perceptual regularities can induce the generation of neural priors at the time of predictive stimulus presentation, possibly conveying sensory-specific information of the predicted consecutive stimulus.

neuroscience↗

bioRxiv2023

Phase coding in phoneme processing slows with age

The comprehension of phonemes is a fundamental component of speech processing which relies on both, temporal fine structure (TFS) and temporal envelope (TE) coding. EEG amplitude in response to phonemes has been identified as indicator of speech performance in hearing aid users. Presbyacusis may also alter neuro-electric responses to phonemes, even with minimally or unaffected hearing thresholds. Elevated speech reception thresholds (SRT) in absence of pure-tone threshold (PTT) elevation suggest central processing deficits. We therefore collected audiometric data (PTT, SRT) and EEG during passive listening in 80 subjects, ranging in age from 18 to 76 years. We confirm phoneme-evoked EEG response amplitude (PEA) as indicator of speech comprehension. Specifically, PEA decreased with elevated SRT, PTT and increased age. As novel observation, we report the temporal delay of phoneme-evoked EEG responses (PED) to increase with age and PTT. The absolute duration of PED, its age-correlation, and the lack of PEA-lateralization combined with the frequency of phoneme stimuli used here suggest a predominantly thalamic generator of phoneme-evoked EEG responses. Hearing loss in extended high-frequencies affects PED more than PEA. In our sample, neural compensation for increased PTT came at the cost of decreased temporal processing speed. Most importantly, PED correlates with SRT and explains SRT-variance in quiet and in ipsilateral noise that PTT cannot. PED was a better predictor of TFS coding in quiet and of TE coding in ipsilateral noise. As PED reflects both TFS and TE coding, thalamic activity may provide integrated information at the gate of neocortex. Significance StatementIntact speech comprehension is essential for social participation which protects against depression and dementia. Age-related hearing loss is a growing problem in aging societies, as hearing deficits constitute the third most important modifiable risk factor for cognitive decline. This work uses electrical brain responses to phonemes in a cohort covering age 18 to 76 years. As the temporal delay of phoneme responses showed the most significant correlations with age and high-frequency thresholds, we demonstrated that speed of neural processing seems essential for speech comprehension. The observed neural signals likely originate from thalamus which receives feedback from neocortex and is embedded in cognitive processing. Developing objective markers for speech processing is key for ensuring cognitive fitness in aging.

systems biology↗

bioRxiv2023

Neural adaptation at stimulus onset and speed of neural processing as critical contributors to speech comprehension independent of hearing threshold or age

Loss of afferent auditory fiber function (cochlear synaptopathy) has been suggested to occur before a clinically measurable deterioration of subjective hearing threshold. This so-called "hidden" hearing loss is characterized by speech comprehension difficulties. We examined young, middle-aged, and older individuals with and without hearing loss using pure-tone (PT) audiometry, short-pulsed distortion-product otoacoustic emissions (DPOAE), auditory brainstem responses (ABR), auditory steady state responses (ASSR), speech comprehension (OLSA), and syllable discrimination in quiet and noise. After normalizing OLSA thresholds for PT thresholds ("PNOT"), differences in speech comprehension still remained and showed no significant dependence on age, allowing us to categorize participants into groups with good, standard, and poor speech comprehension. Listeners with poor speech comprehension in quiet exhibited smaller firing rate adaptions at stimulus onset (as measured by the difference between DPOAE threshold and pure-tone threshold) and delayed supra-threshold ABR waves I-V, suggesting high spontaneous rate low threshold fiber cochlear synaptopathy. In contrast, when speech comprehension was tested in noise, listeners with poor speech comprehension had larger DPOAEs acceptance rate, putatively resulting from altered basilar membrane compression (recruitment). This was linked with higher uncomfortable loudness levels and larger ASSR amplitudes. Moreover, performance in phoneme discrimination was significantly different below (/o/-/u/) and above the phase-locking limit (/i/-/y/), depending on whether vowels were presented in quiet or ipsilateral noise. This suggests that neural firing rate adaptation at stimulus onset is critical for speech comprehension, independent of hearing threshold and age, whereas the recruitment phenomenon counterbalances the loss in speech-in-noise discrimination due to impaired threshold. Significance StatementAge-related hearing loss is the third largest modifiable risk factor for cognitive decline. It has been suggested that the link between hearing loss and cognitive decline is not fully explained by hearing threshold loss. We here suggest that language comprehension deficits may be used as an early indication of future hearing loss and therefore cognitive decline. We found that, independent of age and pure-tone thresholds, speech comprehension in quiet and ipsilateral noise depend on different onset firing-rate adaptations of inner hair cells (measured by DPOAE threshold), along with cochlear synaptopathy of high spontaneous rate auditory nerve fibers and neural spiking synchronicity. These measures may be used as possible future indicators of risk for cognitive decline.

neuroscience↗

bioRxiv2023

Innate immune memory after brain injury drives inflammatory cardiac dysfunction

The enormous medical burden of stroke is not only due to the brain injury itself and the acute systemic effects, but is largely determined by chronic comorbidities that develop secondarily after stroke. We hypothesized that the high rate of comorbidity developing after a stroke might have a shared immunological cause, however, the chronic effects of brain injury on systemic immunity have so far been barely investigated. Here, we identified myeloid innate immune memory as a cause of remote organ dysfunction after stroke. Using single-cell sequencing, we identified persistent pro-inflammatory transcriptomic changes in resident monocytes/macrophages in multiple organs one month after experimental ischemic brain injury, which was particularly abundant in the heart and associated with the development of cardiac fibrosis and diastolic dysfunction. A similar phenotype was seen in myocardial autopsy samples from stroke versus control patients. We observed chronic functional changes in myeloid hematopoiesis driven by post-stroke IL-1{beta}-mediated epigenetic changes. These alterations could be transplanted to naive recipient mice and were sufficient to induce cardiac dysfunction. By effectively blocking the trafficking of pro-inflammatory monocytes from the bone marrow to the heart using a dual CCR2/5 inhibitor, we successfully prevented post-stroke cardiac dysfunction. This approach holds promising potential as a novel immune-targeted secondary prevention therapy. We anticipate that the epigenetic immune reprogramming mechanisms detailed here for the brain-heart axis could be generalized to provide a novel framework for explaining the development of various comorbidities after acute tissue injury in remote organs.

immunology↗

bioRxiv2023

Discrimination of finger movements by magnetomyography with optically pumped magnetometers

Optically pumped magnetometers (OPM) are quantum sensors that offer new possibilities to measure biomagnetic signals. In magnetomyography (MMG), compared to the current standard surface electromyography (EMG), OPM sensors offer the advantage of contactless measurements of muscle activity. However, little is known about the relative performance of OPM-MMG and EMG, e.g. in their ability to detect and classify finger movements. To address this, we recorded simultaneous OPM-MMG and EMG of finger flexor muscles for the discrimination of individual finger movements. Using a deep learning model for movement classification, we found that both sensor modalities were able to discriminate finger movements with above 89% accuracy. Furthermore, model predictions for the two sensor modalities showed high agreement in movement detection (85% agreement; Cohens kappa: 0.45). Our findings show that OPM sensors can be employed for reliable, contactless discrimination of finger movements and incentivize future applications of OPM in magnetomyography.

neuroscience↗

bioRxiv2022

Adult lifespan trajectories of neuromagnetic signals and interrelations with cortical thickness

Oscillatory power and phase synchronization map neuronal dynamics and are commonly studied to differentiate the healthy and diseased brain. Yet, little is known about the course and spatial variability of these features from early adulthood into old age. Leveraging magnetoencephalography (MEG) resting-state data in a cross-sectional adult sample (n = 350), we probed lifespan differences (18-88 years) in connectivity and power and interaction effects with sex. Building upon recent attempts to link brain structure and function, we tested the spatial correspondence between age effects on cortical thickness and those on functional networks. We further probed a direct structure-function relationship at the level of the study sample. We found MEG frequency-specific patterns with age and divergence between sexes in low frequencies. Connectivity and power exhibited distinct linear trajectories or turning points at midlife that might reflect different physiological processes. In the delta and beta bands, these age effects corresponded to those on cortical thickness, pointing to co-variation between the modalities across the lifespan. Structure-function coupling was frequency-dependent and observed in unimodal or multimodal regions. Altogether, we provide a comprehensive overview of the topographic functional profile of adulthood that can form a basis for neurocognitive and clinical investigations. This study further sheds new light on how the brains structural architecture relates to fast oscillatory activity.

neuroscience↗