Biology subjects

Bouvier, J.

Publications and source records attributed to Bouvier, J..

8 recordsLinked to original sources

bioRxiv2026

Bioimpedance spectroscopy assessment of skeletal muscle tissue properties after muscle damage

High intensity and unaccustomed physical activity can induce skeletal muscle damage, while even routine movements can cause similar alterations in patients with neuromuscular disease. However, reliable assessment of muscle damage using indirect markers such as muscle function evaluation, invasive measurements, or imaging techniques is difficult to implement in routine clinical follow-up and sport field settings. Bioimpedance spectroscopy appears as a promising non-invasive, easy-to-use and transportable tool to assess indirect markers of muscle damage. The aim of this study was to determine whether bioimpedance spectroscopy data are sensitive to eccentric exercise-induced muscle damage and if these potential changes mirror responses in muscle function and tissue mechanical properties. Changes in knee extensors maximal isometric contraction torque, muscle soreness, resting rigidity of the quadriceps femoris muscle tissue, and bioimpedance parameters at rest and during maximal isometric contraction were assessed in nine healthy males before, immediately after and in the three days following 120 maximal isokinetic eccentric contractions. Maximal contraction torque was significantly reduced during the three days following the eccentric exercise (up to -24.2%) while muscle soreness and rigidity of the quadriceps femoris were elevated until the second day (+494.4% and +7.6%). Changes in bioimpedance spectroscopy parameters were transiently observed at rest immediately after the damaging exercise, but not in the days that followed. Although the changes in bioimpedance parameters correlated with that of the indirect markers of muscle damage, they had already returned to baseline while functional and mechanical impairments persisted. Therefore, bioimpedance spectroscopy measurements may represent a suitable and cost-effective means of monitoring muscle fatigue.

physiology↗

bioRxiv2026

Motor memory under sleep deprivation: Can physical exercise support consolidation?

Sleep deprivation (SD) is increasingly prevalent and known to impair declarative memory, yet its impacts on the acquisition and consolidation of procedural skills remains unknown. Physical exercise has emerged as a promising intervention for promoting learning and plasticity, but its potential to mitigate SD-induced deficits has never been tested. Here, we investigated whether SD disrupts sequential motor learning (SML) and whether high-intensity interval exercise (HIIE) performed after acquisition can influence consolidation. Forty-eight participants were randomly assigned to one of four groups combining one night of SD or normal sleep condition with HIIE or control intervention. SD elevated cortisol and sleepiness without affecting brain-derived neurotrophic factor or corticospinal excitability. Behaviorally, SD selectively impaired the movement time execution of SML acquisition, while HIIE reduced the movement accuracy during consolidation, regardless of sleep condition. These findings reveal a component-specific vulnerability of procedural memory to SD and challenge the assumption that exercise consistently enhances consolidation following motor learning.

neuroscience↗

bioRxiv2025

High-intensity interval exercise affects explicit sequential motor consolidation with both physical and mental practice

High-intensity interval exercise (HIIE) is known to enhance motor consolidation following physical practice (PP), but its effects on sequential motor learning (SML) through PP or motor imagery (MI) remain unclear. We examined whether HIIE modulates SML consolidation in 48 participants who learned an explicit SML task through PP or MI. Performance was assessed before and after acquisition, after HIIE or rest, and at 24 hours and 7 days. Both PP and MI improved performance, with greater gains for PP (p = 0.042), and both induced intracortical disinhibition (p = 0.03). HIIE increased BDNF (p = 0.044) and lactate levels (p < 0.001), markers typically linked to neuroplasticity, yet unexpectedly impaired SML at early (p < 0.01) and late consolidation (p < 0.05), without affecting excitability. These findings challenge the presumed coupling between exercise-induced biomarkers and behavioral gains, suggesting that HIIE may hinder consolidation when explicit components of motor learning are involved. Significance StatementHIIE is increasingly proposed as a tool to boost neuroplasticity and enhance motor learning. However, whether its benefits extend to all forms of learning remains unclear. Here, we show that both physical and motor imagery practice improve SML and induce intracortical disinhibition, a neurophysiological signature of plasticity. Surprisingly, HIIE impaired SML consolidation at both early and late stages, despite increases in BDNF and lactate, biomarkers typically linked to learning facilitation. This deterioration was observed across both practice modalities and is likely driven by the explicit, cognitively demanding nature of the task. These findings challenge the generalizability of HIIEs beneficial effects and highlight the need to align exercise-based interventions with the specific cognitive-motor demands of the learning task. Such insights are critical for optimizing motor learning strategies in both athletic training and neurorehabilitation.

neuroscience↗

bioRxiv2024

Metabolic engineering of stomatal precursor cells enhances photosynthetic water-use efficiency and vegetative growth under water-deficit conditions in Arabidopsis thaliana

Stomata are epidermal pores that control the exchange of gaseous CO2 and H2O between plants and their environment. Modulating stomatal density can alter this exchange, and thus presents a target for engineering improved crop productivity and climate resilience. Here, we show that stomatal density in Arabidopsis thaliana can be decreased by the expression of a water-forming NAD(P)H oxidase targeted to stomatal precursor cells. We demonstrate that this reduction in stomatal density occurs irrespective of whether the expressed enzyme is targeted to the cytosol, chloroplast stroma, or chloroplast intermembrane space of these cells. We reveal that this decrease in stomatal density occurs in the absence of any measurable impact on stomatal dynamics, or the efficiency or thermal sensitivity of photosynthesis. Consequently, overexpression plants exhibit a higher intrinsic water use efficiency due to an increase in CO2 fixed per unit water transpired. Finally, we demonstrate that this enhanced water-use efficiency translates to an improvement in vegetative growth and biomass accumulation under water-deficit conditions. Together, these results thus provide a novel approach for enhancing plant productivity through metabolic engineering of stomatal density.

plant biology↗

bioRxiv2023

Sensory Feedback and Central Neuronal Interactions in Mouse Locomotion

Locomotion is a complex process involving specific interactions between the central neural controller and the mechanical components of the system. The basic rhythmic activity generated by locomotor circuits in the spinal cord defines rhythmic limb movements and their central coordination. The operation of these circuits is modulated by sensory feedback from the limbs providing information about the state of the limbs and the body. However, the specific role and contribution of central interactions and sensory feedback in the control of locomotor gait and posture remain poorly understood. We use biomechanical data on quadrupedal locomotion in mice and recent findings on the organization of neural interactions within the spinal locomotor circuitry to create and analyze a tractable mathematical model of mouse locomotion. The model includes a simplified mechanical model of the mouse body with four limbs and a central controller composed of four rhythm generators, each operating as a state machine controlling the state of one limb. Feedback signals characterize the load and extension of each limb as well as postural stability (balance). We systematically investigate and compare several model versions and compare their behavior to existing experimental data on mouse locomotion. Our results highlight the specific roles of sensory feedback and some central propriospinal interactions between circuits controlling fore and hind limbs for speed-dependent gait expression. Our models suggest that postural imbalance feedback may be critically involved in the control of swing-to-stance transitions in each limb and the stabilization of walking direction.

systems biology↗

bioRxiv2022

Slow molecular evolution of rubisco limits adaptive improvement of CO2 assimilation

Rubisco is the primary entry point for carbon into the biosphere. However, rubisco is widely regarded as inefficient leading many to question whether the enzyme can adapt to become a better catalyst. Through a phylogenetic investigation of the molecular and kinetic evolution of Form I rubisco we demonstrate that rubisco is not stagnant. Instead, we demonstrate rbcL is among the 1% of slowest evolving genes and enzymes on Earth, accumulating one nucleotide substitution every 0.9 million years and one amino acid mutation every 7.2 million years. Despite this, we demonstrate that rubisco catalysis is continuing to evolve toward improved CO2/O2 specificity, carboxylase turnover, and carboxylation efficiency. Consistent with this kinetic adaptation, we reveal that increased rubisco evolution leads to a concomitant improvement in leaf-level CO2 assimilation. Thus, rubisco is continually evolving toward improved catalytic efficiency and CO2 assimilation in plants.

plant biology↗

bioRxiv2021

Upregulation of breathing rate during running exercise by central locomotor circuits

While respiratory adaptation to exercise is compulsory to cope with the increased metabolic supply to body tissues and with the necessary clearing of metabolic waste, the neural apparatus at stake remains poorly identified. Using viral tracing, ex vivo and in vivo optogenetic and chemogenetic interference strategies in mice, we unravel interactive locomotor and respiratory networks nodes that mediate the respiratory rate increase that accompanies a running exercise. We show that the mesencephalic locomotor region (MLR) and the lumbar spinal locomotor pattern generator (lumbar CPG), which respectively initiate and execute the locomotor behavior, access the respiratory network through distinct entry points. The MLR directly projects onto the inspiratory rhythm generator, the preBotzinger complex (preBotC), and can trigger a moderate increase of respiratory frequency, prior to, or even in the absence of, locomotion. In contrast, the lumbar CPG projects onto the retrotrapezoid nucleus (RTN) that in turn contacts the preBotC to enforce, during effective locomotion, higher respiratory frequencies. These data expand, on the one hand, the functional implications of the MLR beyond locomotor initiation to a bona fide respiratory modulation. On the other hand, they expand the adaptive respiratory ambitions of the RTN beyond chemoception to "locomotor- ception".

neuroscience↗

bioRxiv2020

Independent respiratory and locomotor rhythms in running mice

Examining whether and how the rhythms of limb and breathing movements interact is highly informative about the mechanistic origin of hyperpnoea to exercise. However, studies have failed to reveal regularities. In particular, whether breathing frequency is inherently proportional to limb velocity and/or imposed by a synchronization of breaths to strides is still unclear. Here, we examined the specifications of respiratory changes during running in mice, the premier model for investigating, in a standardized manner, complex integrative tasks including adaptive breathing. We show that respiratory rate increases during running to a fixed and stable value, irrespective of trotting velocities and of inclination. Yet, respiratory rate was further enhanced during gallop. We also demonstrate the absence of temporal coordination of breaths to strides at any speed, intensity or gait. Our work thus highlights a hardwired mechanism that sets respiratory frequency independently of limb movements but in relation with the engaged locomotor program.

neuroscience↗