Biology subjects

Huber, D.

Publications and source records attributed to Huber, D..

At least 19 recordsLinked to original sources

bioRxiv2026

A Physiologically Detailed Biomechanical Model of the Mouse Distal Forelimb for Simulation of Fine Motor Control

This study presents a physiologically detailed biomechanical model of the mouse distal forelimb that incorporates intrinsic musculature, tendon routing, and digit-level skeletal anatomy, features simplified or omitted in existing musculoskeletal models. Using high-resolution anatomical reconstruction and computational modeling, we created a physiological representation of the wrist and digits capable of simulating complex forelimb movements. The model enables simulation of coordinated distal forelimb movement and digit-level muscle behavior during grasping-related tasks. Simulations were performed for multiple tasks, including grasping, grasping with supination, wrist flexion, and digit I flexion, with analysis focused on the grasping task due to its integration of both intrinsic and extrinsic musculature. Model performance was evaluated through comparisons of marker trajectories between torque-driven reference motion and muscle-driven simulations, temporal shuffle control, and comparisons between experimentally recorded electromyography (EMG) activity and model-predicted muscle excitation profiles. The model successfully reproduced coordinated distal forelimb kinematics, demonstrated strong agreement between torque-driven and muscle-driven simulation approaches, and generated physiologically plausible muscle excitation patterns consistent with experimentally observed EMG activity during grasping-related movement. These findings establish the model as a framework for studying fine motor control, neuromuscular coordination, and movement-related impairments in mice while providing a foundation for future investigation of neurological disorders and their underlying biomechanical mechanisms.

bioengineering↗

bioRxiv2026

Whole human organ clearing and multimodal mapping

Human anatomy has traditionally been studied using low-resolution approaches such as cadaveric dissection and conventional medical imaging, limiting our understanding of macroscopic structures. Tissue clearing has emerged as a transformative approach, enabling three-dimensional mapping of organs at microscopic resolution, and offering the opportunity to interrogate anatomy across scales. However, its application to human organs remains challenging due to their size, density and optical properties. Here, we establish multiorgan CleLight (mCleLight) as a generalizable method for clearing, labeling and imaging whole human tissues. mCleLight is broadly applicable across major organ systems and enables the analysis of particularly challenging specimens, including highly heterogeneous samples, dense bones, pigmented tissues and decades-old formalin-fixed archival material. We demonstrate that controlled photoclearing is critical across human tissues both for efficient clearing and for quenching endogenous fluorescence, thereby substantially improving imaging depth as compared to previous methods. mCleLight allows specific labeling and quantitative analysis of complex extended structures such as collagen fibers, vasculature, and innervation, while preserving anatomical relationships, which cannot be easily done with classical histology. We integrated mCleLight into a pipeline with clinical imaging to achieve a comprehensive, multiscale understanding of organ architecture. We demonstrate the voxel-by-voxel alignment between MRI and microscopy datasets, merging cellular-scale detail and protein- specific labeling with macroscopic medical imaging. By bridging the gap between imaging scales and modalities, mCleLight provides a versatile method for integrated three- dimensional histological mapping and macroscopic anatomy of human organs in health and disease.

cell biology↗

bioRxiv2025

Translating Music to Touch: Exploring Tactile Perception of Pitch, Roughness, and Pleasantness

Music is a rich multisensory experience, yet individuals with hearing impairments often lack access to this important aspect of culture. As tactile technologies advance, there is growing interest in whether musical information can be conveyed through vibration. This study investigates how core dimensions of auditory music perception, pitch, roughness, and pleasantness, can be translated into the tactile domain. Participants were asked to rate these perceptual dimensions in response to sinusoidal and complex waveforms, including amplitude-modulated signals, sawtooth, and missing fundamental stimuli. Perceived pitch showed a systematic relationship with stimulus frequency for most participants, suggesting that tactile devices could at least partially convey some form of simple melodic patterns. The sawtooth waveform emerged as particularly effective for representing pitch changes, underscoring the role of rapid temporal transitions in tactile pitch encoding. Roughness ratings were negatively correlated with pleasantness, mirroring well-established findings in auditory perception. Waveforms with sudden temporal changes or rapid amplitude modulations were consistently judged as less pleasant. Taken together, these findings in normal hearing participants may inform the design of vibrotactile displays that could support access to selected music relevant perceptual dimensions, although generalization to people with hearing loss remains to be tested. Importantly, our results highlight the crucial role of the fast temporal envelope rather than the temporal fine structure, in shaping vibrotactile perception. Consistent with this interpretation, our data provide evidence for a tactile analog of the auditory missing fundamental phenomenon, reinforcing the idea that tactile pitch perception primarily relies on envelope periodicity rather than the presence of specific frequency components.

neuroscience↗

bioRxiv2025

iSleep: Continuous, binocular pupil tracking in sleep and reduced consciousness for physiological monitoring, predictions and interventions

Monitoring pupil dynamics is a key tool in understanding arousal. Pupil size can serve as a biomarker for the autonomic nervous system balance as well as for identifying brain states. While internal states can also be self-reported when awake, automated detection and non-invasive monitoring is crucial during sleep and reduced consciousness. Here, we introduce iSleep, an innovative pupil tracking and analysis framework for sleep in humans. It features comfortable, humidified eye-tracking goggles and a platform for integrated analysis and prediction capabilities. We show that iSleep allows safe and continuous access to binocular pupil size and ocular dynamics during sleep and anesthesia. iSleep reveals that pupillary fluctuations correlate tightly with brain activity, heartbeat, and breathing, and can reliably predict brain states. Pupil constrictions reflect parasympathetic drive and likely serve a protective function for deep sleep stability; while dilations indicate arousals. Unexpectedly, we observed a decoupling of binocular movements during periods of sleep, indicating alterations in reflexes which usually govern voluntary eye movements. Finally, iSleep was tested in surgery patients under general anesthesia, revealing dynamic pupil changes to noxious stimuli, suggesting the potential for nociception monitoring during surgeries. In summary, iSleep offers an easy-to-use, robust alternative to read out brain states during sleep and anesthesia, opening new avenues in monitoring, diagnostics, and treatments, previously obscured by closed eyelids.

neuroscience↗

bioRxiv2025

BlueBerry: Closed-loop wireless optogenetic manipulation in freely moving animals

Optogenetics is a powerful approach for linking neural activity to behavior by enabling precise manipulation of defined neuronal populations. Recent advances in wireless technologies have led to remotely controlled optogenetic devices that facilitate the study of more complex behaviors, including social interactions. However, implementing real-time, automated, closed-loop experiments in large-scale, naturalistic environments and in groups of interacting animals remains challenging. Moreover, many existing devices are difficult to reproduce, requiring specialized engineering expertise or fabrication facilities that are not widely available. Here we introduce BlueBerry (www.OptoBlueBerry.org), a lightweight (1.4 g), battery powered, multi-channel wireless optogenetic device that is openly available for the scientific community and can be assembled entirely from off-the-shelf-components. BlueBerry combines robust long-range wireless communication with flexible control of stimulation parameters, making it particularly suited for behavior-triggered optogenetic experiments in large arenas and in multiple freely interacting animals. We demonstrate that BlueBerry can not only guide decision making during large-scale navigation, but also deliver individually controlled, behavior-triggered optogenetic stimulation to multiple freely interacting mice, enabling modulation of social dynamics in real-time. The open availability, modular design, and straightforward integration with existing behavioral frameworks make BlueBerry a practical and scalable tool for systems neuroscience.

neuroscience↗

bioRxiv2024

A novel biomechanical model of the mouse forelimb predicts muscle activity in optimal control simulations of reaching movements

Mice are key model organisms in neuroscience and motor systems physiology. Fine motor control tasks performed by mice have become widely used in assaying neural and biophysical motor system mechanisms. Although fine motor tasks provide useful insights into behaviors which require complex multi-joint motor control, there is no previously developed physiological biomechanical model of the adult mouse forelimb available for estimating kinematics nor muscle activity or kinetics during behaviors. Here, we developed a musculoskeletal model based on high-resolution imaging of the mouse forelimb that includes muscles spanning the neck, trunk, shoulder, and limbs. Physics-based optimal control simulations of the forelimb model were used to estimate in vivo muscle activity present when constrained to the tracked kinematics during reaching movements. The activity of a subset of muscles was recorded and used to assess the accuracy of the muscle patterning in simulation. We found that the synthesized muscle patterning in the forelimb model had a strong resemblance to empirical muscle patterning, suggesting that our model has utility in providing a realistic set of estimated muscle excitations over time when given a kinematic template. The strength of the similarity between empirical muscle activity and optimal control predictions increases as mice performance improves throughout learning of the reaching task. Our computational tools are available as open-source in the OpenSim physics and modeling platform. Our model can enhance research into limb control across broad research topics and can inform analyses of motor learning, muscle synergies, neural patterning, and behavioral research that would otherwise be inaccessible. NEW & NOTEWORTHYInvestigations into motor planning and execution lack an accurate and complete model of the forelimb, which could bolster or expand on findings. We sought to construct such a model using high detail scans of murine anatomy and prior research into muscle physiology. We then used the model to predict muscle excitations in a set of reaching movements and found that it provided accurate estimations and provided insight into an optimal-control framework of motor learning.

bioengineering↗

bioRxiv2024

Lamellar Schwann cells in the Pacinian corpuscle potentiate vibration perception

Pacinian corpuscles are among the most sensitive mechanoreceptors found in vertebrates and they are tuned to vibrations in the highest perceptible frequency range (100-2000Hz). One of their anatomical hallmarks is the onion-like cell layers surrounding the central axon. The innermost layers consist of [~]60 densely packed lamellar Schwann cells (LSCs), whose function remains largely unknown. Using high-resolution 3D electron microscopy we found that LSCs in Pacinian corpuscles of the mouse hindlimb do not form concentric rings, but complex, multilayered and intertwining assemblies that are connected via an estimated 5805.1 desmosomes and 4142.5 gap-junctions. LSCs make multiple converging contacts with the afferent axon and its protrusions with desmosomes. Using optogenetic manipulations of LSCs we demonstrate that their activation does not only drive reliable time-locked spiking in the axon, but that their inactivation significantly elevates the thresholds in-situ and increases perceptual thresholds behaviorally. Together these findings provide evidence that LSCs are a key element of somatosensory processing, actively potentiating mechanosensitivity in Pacinian corpuscles. HighlightsO_LIHigh-resolution electron microscopy reveals details of the Pacinian corpuscle C_LIO_LILamellar Schwann cells form claw-like structures with converging axonal contacts C_LIO_LISchwann-cell modulation bidirectionally affects neural coding of Pacinian afferent C_LIO_LIInactivation of lamellar Schwann-cells increases perceptual thresholds C_LI

neuroscience↗

bioRxiv2024

Human footprint and forest disturbance reduce space use of brown bears across Europe.

Three-quarters of the planets land surface has been altered by humans, with consequences for animal ecology, movements and related ecosystem functioning. Species often occupy wide geographical ranges with contrasting human disturbance and environmental conditions, yet, limited data availability across species ranges has constrained our understanding of how human impact and resource availability jointly shape intraspecific variation of animal space use. Leveraging a unique dataset of 752 annual GPS movement trajectories from 370 brown bears (Ursus arctos) across the species range in Europe, we investigated the effects of human impact (i.e., human footprint index), resource availability, forest cover and disturbance, and area-based conservation measures on brown bear space use. We quantified space use at different spatio-temporal scales during the growing season (May - September): home range size; representing general space requirements, 10-day long-distance displacement distances, and routine 1-day displacement distances. We found large intraspecific variation in brown bear space use across all scales, which was profoundly affected by human footprint index, vegetation productivity, and recent forest disturbances creating opportunity for resource pulses. Bears occupied smaller home ranges and moved less in more anthropized landscapes and in areas of higher resource availability. Forest disturbances reduced space use while contiguous forest cover promoted longer daily movements. The amount of strictly protected and roadless areas within bear home ranges were too small to affect space use. Anthropized landscapes may hinder the expansion of small and isolated populations, such as the Apennine and Pyrenean, and obstruct population connectivity, for example between the Alpine or Carpathian with the Dinaric Pindos populations. Our findings call for actions to maintain bear movements across landscapes with high human footprint, for example by maintaining forest integrity, to support viable bear populations and their ecosystem functions.

ecology↗

bioRxiv2024

eLemur: A cellular-resolution 3D atlas of the mouse lemur brain

The gray mouse lemur (Microcebus murinus), one of the smallest living primates, emerges as a promising model organism for neuroscience research. This is due to its genetic similarity to humans, its evolutionary position between rodents and humans, and its primate-like features encapsulated within a rodent-sized brain. Despite its potential, the absence of a comprehensive reference brain atlas impedes the progress of research endeavors in this species, particularly at the microscopic level. Existing references have largely been confined to the macroscopic scale, lacking detailed anatomical information. Here, we present eLemur, a new resource, comprising a repository of high-resolution brain-wide images immunostained with multiple cell type and structural markers, elucidating the cyto- and chemoarchitecture of the mouse lemur brain. Additionally, it encompasses a segmented two-dimensional (2D) reference and 3D anatomical brain atlas delineated into cortical, subcortical, and other vital regions. Furthermore, eLemur includes a comprehensive 3D cell atlas, providing densities and spatial distributions of non-neuronal and neuronal cells across the mouse lemur brain. Accessible via a web-based viewer (https://eeum-brain.com/#/lemurdatasets), the eLemur resource streamlines data sharing and integration, fostering the exploration of new hypotheses and experimental designs using the mouse lemur as a model organism. Moreover, in conjunction with the growing 3D datasets for rodents, non-human primates, and humans, our eLemur 3D digital framework enhances the potential for comparative analysis and translation research, facilitating the integration of extensive rodent study data into human studies. Significance StatementThe gray mouse lemur (Microcebus murinus) represents a promising model for neuroscience research, offering insights into brain structure and function due to its genetic and evolutionary proximity to humans and rodents. Our development of eLemur, a comprehensive 3D digital brain atlas, fills critical gaps in microscopic data availability, enabling nuanced investigations at cellular resolutions. This resource not only enhances our understanding of the mouse lemur brain but also catalyzes broader neuroscience endeavors. By facilitating data sharing and integration, eLemur empowers researchers to explore novel hypotheses and experimental designs. Moreover, its compatibility with existing neuroanatomy frameworks and the growing repository of 3D datasets positions eLemur as a pivotal tool for advancing basic and translational neuroscience studies.

neuroscience↗

bioRxiv2023

Continuous estimation of reaching space in superficial layers of the motor cortex

Motor cortex plays a key role in controlling voluntary arm movements towards spatial targets. The cortical representation of spatial information has been extensively studied and was found to range from combinations of muscle synergies to cognitive maps of locations in space. How such abstract representations of target space evolve during a behavior, how they integrate with other behavioral features and what role they play in movement control is less clear. Here we addressed these questions by recording the activity of layer 2/3 (L2/3) neurons in the motor cortex using two-photon calcium imaging in head-restrained mice, while they reached for water droplets presented at different spatial locations around their snout. Our results reveal that a majority (>80%) of L2/3 neurons with task-related activity are target-space selective and their activity is contingent on a single target position in an ego-centric reference frame. This spatial framework is preferentially organized along three cardinal directions (Center, Left and Right). Surprisingly, the coding of target space is not limited to the activity during movement planning or execution, but is also predominant during preceding and subsequent phases of the task, and even persists beyond water consumption. More importantly, target specificity is independent of the movement kinematics and is immediately updated when the target is moved to a new position. Our findings suggest that, rather than descending motor commands, the ensemble of L2/3 neurons in the motor cortex conjointly encode internal (behavioral) and external (spatial) aspects of the task, playing a role in higher-order representations related to estimation processes of the ongoing actions.

neuroscience↗

bioRxiv2023

Transformation of neural coding for vibrotactile stimuli along the ascending somatosensory pathway

Perceiving substrate vibrations is a fundamental component of somatosensation. In mammals, action potentials fired by rapidly adapting mechanosensitive afferents are known to reliably time lock to the cycles of a vibration. This stands in contrast to coding in the higher-order somatosensory cortices, where neurons generally encode vibrations in their firing rates, which are tuned to a preferred vibration frequency. How and where along the ascending neuraxis is the peripheral afferent temporal code of cyclically entrained action potentials transformed into a rate code is currently not clear. To answer this question, we probed the encoding of vibrotactile stimuli with electrophysiological recordings along major stages of the ascending somatosensory pathway in mice. Recordings from individual primary sensory neurons in lightly anesthetized mice revealed that rapidly adapting mechanosensitive afferents innervating Pacinian corpuscles display phase-locked spiking for vibrations up to 2000 Hz. This precise temporal code was reliably preserved through the brainstem dorsal column nuclei. The main transformation step was identified at the level of the thalamus, where we observed a significant loss of phase-locked spike timing information accompanied by a further narrowing of tuning curve widths. Using optogenetic manipulation of thalamic inhibitory circuits, we found that parvalbumin-positive interneurons in thalamic reticular nucleus participate in sharpening frequency selectivity and disrupting the precise spike timing of ascending neural signals encoding vibrotactile stimuli. To test the functional implications of these different neural coding mechanisms, we applied frequency-specific microstimulation within the brainstem, which generated frequency selectivity reminiscent of real vibration responses in the somatosensory cortex, whereas microstimulation within thalamus did not. Finally, we applied microstimulation in the brainstem of behaving mice and demonstrated that frequency-specific stimulation could provide informative and robust signals for learning. Taken together, these findings not only reveal novel features of the computational circuits underlying vibrotactile sensation, but could also guide biomimetic stimulus strategies to activate specific nuclei along the ascending somatosensory pathway for sensory neural prostheses.

neuroscience↗

bioRxiv2023

Emergence of a somatosensory tonotopic map for substrate vibration in the brainstem

Perceiving substrate vibrations is a fundamental component of tactile perception. The wide frequency spectrum of vibrations is covered by integrating responses of multiple mechanoreceptors that innervate various subtypes of mechanosensitive end organs, each preferring a specific range: Merkel cells (0.5-10Hz), Meissner corpuscles (10-150Hz) and Pacinian corpuscles (150-1000Hz) in primates. As the density of different end organs greatly varies across the body, each body part potentially has a specific frequency preference. How location (somatotopy) and frequency tuning (tonotopy) are processed along the ascending neuraxis and how they converge to drive responses of individual neurons is poorly understood. In this study, we address this question by combining in vivo peripheral electrophysiology and two-photon calcium imaging along the entire dorsal column-medial lemniscal pathway, including the dorsal root ganglia, dorsal column nuclei (DCN), the thalamus and the cortex. Surprisingly, we found that both frequency, as well as location, are organised into structured maps in the DCN. Furthermore, both maps are intimately related at the fine spatial scale with parallel map gradients that are consistent across the depth of the DCN and preserved along the ascending pathway. Additional sensory mapping experiments based on peripheral characterisation revealed that the tonotopic map only partially reflects the distribution of end organs in the skin and deep tissue. Instead, we show that the emergence of the finescale tonotopy is probably due to the selective dendritic sampling from axonal afferents, right at the first synaptic relay. Taken together, we conclude DCN neural circuits are key to the emergence of these two fine-scale topological organisations in early somatosensory pathways. The underlying computational principle is intriguingly similar to the integration of multiple functional maps along the ascending visual pathways, suggesting a universal law governing the optimization of sensory systems.

neuroscience↗

bioRxiv2023

Including biotic interactions in species distribution models improves the understanding of species niche: a case of study with the brown bear in Europe

Biotic interactions are expected to influence species responses to climate change, but they are usually not included when predicting future range shifts. We assessed the importance of biotic interactions to understand future consequences of climate and land use change for biodiversity using as a model system the brown bear (Ursus arctos) in Europe. By including biotic interactions using the spatial variation of energy contribution and habitat models of each food species, we showed that the use of biotic factors considerably improves our understanding of the distribution of brown bears. Predicted future range shifts, which included changes in the distribution of food species, varied greatly when considering various scenarios of change in biotic factors, warning about future indirect climate change effects. Our study confirmed that advancing our understanding of ecological networks of species interactions will improve future scenarios of biodiversity change, which is key for conserving biodiversity and ecosystem services.

ecology↗

bioRxiv2023

Mobile brain imaging in butoh dancers: from rehearsals to public performance

Dissecting the neurobiology of dance would shed light on a complex, yet ubiquitous, form of human communication. In this experiment, we sought to study, via mobile electroencephalography (EEG), the brain activity of five experienced dancers while dancing butoh, a postmodern dance that originated in Japan. We report the experimental design, methods, and practical execution of a highly interdisciplinary project that required the collaboration of dancers, engineers, neuroscientists, musicians, and multimedia artists, among others. We explain in detail how we technically validated all our EEG procedures (e.g., via impedance value monitoring) and how we minimized potential artifacts in our recordings (e.g., via electrooculography and inertial measurement units). We also describe the engineering details and hardware that enabled us to achieve synchronization between signals recorded in different sampling frequencies, and a signal preprocessing and denoising pipeline that we have used to re-sample our data and remove power line noise. As our experiment culminated in a live performance, where we generated a real-time visualization of the dancers interbrain synchrony on a screen via an artistic brain-computer interface, we outline all the methodology (e.g., filtering, time-windows, equation) we used for online bispectrum estimations. We also share all the raw EEG data and codes we used in our recordings. We, lastly, describe how we envision that the data could be used to address several hypotheses, such as that of interbrain synchrony or the motor theory of vocal learning. Being, to our knowledge, the first study to report synchronous and simultaneous recording from five dancers, we expect that our findings will inform future art-science collaborations, as well as dance-movement therapies.

neuroscience↗

bioRxiv2022

"Leap before you look": Conditions that promote implicit visuomotor adaptation without explicit learning

When learning a novel visuomotor mapping (e.g., mirror writing), accuracy can improve quickly through explicit learning (e.g., move left to go right) but after considerable practice, implicit learning takes over, producing fast, natural movements. This implicit learning occurs automatically, but it has been unknown whether explicit learning is similarly obligatory. Using a reaching task with a 90-degree rotation between screen position and movement direction, we found that explicit learning could be "turned off" by introducing the rotation gradually (increments of 10-degrees) and instructing participants to move quickly. These specific conditions were crucial, because both explicit and implicit learning occurred if the rotation occurred suddenly, if participants were told to emphasize accuracy, or if visual feedback during movement was removed. We reached these conclusions by examining the time course of learning (e.g., whether there was fast improvement followed by a long tail of additional improvement), by examining the aftereffects of learning when the rotation was abruptly removed, and by using formal model comparison between a dual-state (explicit and implicit) versus a single-state learning model as applied to the data. Author summaryIn some situations, the relationship between motion direction and what we see is different than normal. For instance, try using a computer mouse that is held sideways (a 90-degree rotation). When first encountering this situation, people move carefully, using explicit strategies (e.g., move right to go up). However, after many learning trials, motion becomes automatic (implicit) and natural. Prior results found that implicit visuomotor learning always occurs with enough experience. In our study, we found that this is not true of explicit visuomotor learning; in some situations, explicit learning can be turned off. More specifically, we found that this occurs when the novel visuomotor situation is: 1) introduced gradually (e.g., a gradual introduction of 90-degree rotation in steps of 10 degrees); 2) when there is pressure to move quickly; and 3) with real-time onscreen views of the motion path. If any of these three components are missing, then people use explicit learning. These conclusions were reached by examining the time course of learning (e.g., whether there was both fast and slow learning as assessed with mathematical models) and by examining the tendency to automatically move in the opposite direction from the rotation when the rotation is abruptly removed after learning.

neuroscience↗

bioRxiv2021

Virtual reality-based sensorimotor adaptation shapes subsequent spontaneous and naturalistic stimulus-driven brain activity

Our everyday life summons numerous novel sensorimotor experiences, to which our brain needs to adapt in order to function properly. However, tracking plasticity of naturalistic behaviour and associated brain modulations is challenging. Here we tackled this question implementing a prism adaptation training in virtual reality (VRPA) in combination with functional neuroimaging. Three groups of healthy participants (N=45) underwent VRPA (with a spatial shift either to the left/right side, or with no shift), and performed fMRI sessions before and after training. To capture modulations in free-flowing, task-free brain activity, the fMRI sessions included resting state and free viewing of naturalistic videos. We found significant decreases in spontaneous functional connectivity between large-scale cortical networks - namely attentional and default mode/fronto-parietal networks - only for adaptation groups. Additionally, VRPA was found to bias visual representations of naturalistic videos, as following rightward adaptation, we found upregulation of visual response in an area in the parieto-occipital sulcus (POS) in the right hemisphere. Notably, the extent of POS upregulation correlated with the size of the VRPA induced after-effect measured in behavioural tests. This study demonstrates that a brief VRPA exposure is able to change large-scale cortical connectivity and correspondingly bias the representation of naturalistic sensory inputs. Significance statementIn the current work, we tested how a brief sensorimotor experience changes subsequent brain activity and connectivity. Using virtual reality (VR) as a tool for sensorimotor training opens a window for creating otherwise impossible sensory experiences and sensorimotor interactions. Specifically, we studied how VR adaptation training in ecological conditions modulates spontaneous functional connectivity and brain representation of naturalistic real-life-like stimuli. Previous adaptation studies used artificial, lab-designed setups both during adaptation and while measuring subsequent aftereffects. Testing brain response while observing naturalistic stimuli and in resting state allowed us to stay as close as possible to naturalistic real-life-like conditions, not confounded by performance during a task. The current work demonstrates how rapid changes in free-flowing brain activity and connectivity occur following short-term VR visuomotor adaptation training in healthy individuals. Moreover, we found a link between sensory responses to naturalistic stimuli and adaptation-induced behavioural aftereffect, thus demonstrating a common source of training-induced spatial recalibration, which affects both behaviour and brain representations of naturalistic stimuli. These findings might have meaningful implications both for understanding the mechanisms underlying visuomotor plasticity in healthy individuals and for using VR adaptation training as a tool for rehabilitating brain-damaged patients suffering from deficits in spatial representation.

neuroscience↗

bioRxiv2020

Common computational principle for vibro-tactile pitch perception in mouse and human

We live surrounded by vibrations generated by moving objects. These oscillatory stimuli can produce sound (i.e. airborne waves) and propagate through solid substrates. Pitch is the main perceptual characteristic of sound, and a similar perceptual attribute seems to exist in the case of substrate vibrations: vibro-tactile pitch. Here, we establish a mechanistic relationship between vibro-tactile pitch perception and the actual physical properties of vibrations using behavioral tasks, in which vibratory stimuli were delivered to the human fingertip or the mouse forelimb. The resulting perceptual reports were analyzed with a model demonstrating that physically different combinations of vibration frequencies and amplitudes can produce equal pitch perception. We found that the perceptually indistinguishable but physically different stimuli follow a common computational principle in mouse and human. It dictates that vibro-tactile pitch perception is shifted with increases in amplitude toward the frequency of highest vibrotactile sensitivity. These findings suggest the existence of a fundamental relationship between the seemingly unrelated concepts of spectral sensitivity and pitch perception.

neuroscience↗

bioRxiv2020

AscA (YecA) is a molecular chaperone involved in Sec-dependent protein translocation in Escherichia coli

Proteins that are translocated across the cytoplasmic membrane by Sec machinery must be in an unfolded conformation in order to pass through the protein-conducting channel during translocation. Molecular chaperones assist Sec-dependent protein translocation by holding substrate proteins in an unfolded conformation in the cytoplasm until they can be delivered to the membrane-embedded Sec machinery. For example, in Escherichia coli, SecB binds to a subset of unfolded Sec substrates and delivers them to the Sec machinery by interacting with the metal-binding domain (MBD) of SecA, an ATPase required for translocation in bacteria. Here, we describe a novel molecular chaperone involved Sec-dependent protein translocation, which we have named AscA (for accessory Sec component). AscA contains a metal-binding domain (MBD) that is nearly identical to the MBD of SecA. In vitro binding studies indicated that AscA binds to SecB and ribosomes in an MBD-dependent fashion. Saturated transposon mutagenesis and genetics studies suggested that AscA is involved in cell-envelope biogenesis and that its function overlaps with that of SecB. In support of this idea, AscA copurified with a range of proteins and prevented the aggregation of citrate synthase in vitro. Our results suggest that AscA is molecular chaperone and that it enhances Sec-dependent protein translocation by delivering its substrate proteins to SecB. IMPORTANCEThis research describes the discovery of a novel molecular chaperone, AscA (YecA). The function of AscA was previously unknown. However, it contains a small domain, known as the MBD, suggesting it could interact with the bacterial Sec machinery, which is responsible for transporting proteins across the cytoplasmic membrane. The work described this study indicates that the MBD allows AscA to bind to both the protein synthesis machinery and the Sec machinery. The previously function of the previously uncharacterised N-terminal domain is that of a molecular chaperone, which binds to unfolded substrate proteins. We propose that AscA binds to protein substrates as they are still be synthesised by ribosomes in order to channel them into the Sec pathway.

molecular biology↗