Дисертації з теми "Unités motrices (UM)"
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Ayachi, Fouaz Sofiane. "Étude du recrutement des unités motrices par analyse du signal EMG de surface." Compiègne, 2011. http://www.theses.fr/2011COMP1998.
Повний текст джерелаThe central nervous system control the movement through the activation of the motors units (MUs), the smallest muscle functional structure. The MU produce electrical activity that can be detected by the technique of surface electromyography (sEMG). The stochastic nature of EMGs signal is mainly due to the superposition of trains of MU action potentials ( MUAPT) (spatial recruitment), the MUAPT are characterized by their discharge frequency (temporal recruitment) and the shape of the action potential (PA), which depends on some factors methodological and intrinsic to the muscle. The aim of this thesis is to study the possibilities and limitations of using the shape analysis of the EMGs signal’s probability density function (DP) as an indicator on MU recruitment strategies and motor control. This analysis seems relevant since the EMGs signal is the sum of random processes, the MUAPT. The contribution of this thesis is divided into two parts : the proposal of a complete model generation inspired by recent work from the literature. This model takes into consideration, for the EMGs signal generation, many physiological, anatomical and nervous parameters, as well as the force generation. Such consideration allows for greater realism in the simulation. The second part concerns several studies, simulation and experimental analysis of EMGs monopolar signals detected on the biceps brachii during isometric contractions isotonic (constant force) / anisotonique (graduated force). The aim is to extract information on the pattern of MU recruitment from these signals. In this context, we tested two approaches based on the shape analysis of the EMGs signal’s DP which are the Higher Order Statistics (HOS), and a recent algorithm, the Core Shape Modeling (CSM). The results indicate a high sensitivity of the proposed descriptors for separating classes of signals (force, sync level of the discharge), the filtering effect of adipose tissue and non propagating component. The efficiency of the classification depends the other hand of the anatomy and the number of MU which composed the muscle. For neuronal factors, both recruitment strategies tested give similar trends with one of them is physiologically more realistic. In addition, analysis of shape (SOS), in some cases, gives us information about muscle anatomy of the concerned muscle, in terms of MU position relative to the electrode. Concerning performance of classification, the algorithm CSM gives a result relatively better than SOS approach, either in simulation or experimentation. To summarize, this thesis is listed as an exploratory process of the shape analysis potential of the EMGs signal’s DP in order to extract the information on the muscular activation’s modalities. A lot of efforts are still required in accordance with the perspectives offered
Mellah, Samira. "Etude des effets de la préparation motrice sur la musculature : modalités de décharge des unités motrices et rôle de la voie corticospinale." Aix-Marseille 3, 1990. http://www.theses.fr/1990AIX30041.
Повний текст джерелаRomaiguère, Patricia. "Propriétés biomécaniques et modalités d'activation volontaire et réflexe des unités motrices des muscles extenseurs du carpe chez l'homme." Aix-Marseille 1, 1990. http://www.theses.fr/1990AIX11290.
Повний текст джерелаTyc, François. "Les interactiond neuro-musculaires : étude des effets de la dénervation partielle sur les propriétés des unités motrices d'un muscle rapide." Aix-Marseille 2, 1995. http://www.theses.fr/1995AIX22071.
Повний текст джерелаAimonetti, Jean-Marc. "Réflexes et régulations d'origine proprioceptive lors de contractions volontaires : étude sur unités motrices identifiées des muscles extenseurs du carpe chez l'homme." Aix-Marseille 1, 1999. http://www.theses.fr/1999AIX11064.
Повний текст джерелаCormery, Bruno. "Adaptations fonctionnelles des unités motrices à la suite d'une paralysie complète induite par l'application chronique de tetrodotoxine sur le nerf sciatique." Aix-Marseille 2, 2000. http://www.theses.fr/2000AIX22065.
Повний текст джерелаChauvet, Eric. "Une approche de la décomposition de l'EMG de surface : application à la caractérisation des unités motrices et à la localisation des zones d'activités musculaires." Compiègne, 2003. http://www.theses.fr/2003COMP1483.
Повний текст джерелаSturm, Hendrik. "Variabilité, synchronisation et cohérence de l'activité des unités motrices chez l'homme : application à l'étude de la réorganisation du réseau afférent motoneuronal en fonction de la tâche." Aix-Marseille 2, 1999. http://www.theses.fr/1999AIX22036.
Повний текст джерелаGioux, Maxime. "Modifications des proprietes mecaniques du muscle squelettique produites par la contraction d'unites motrices. Influence d'une immobilisation prolongee d'un muscle sur ses unites motrices et ses fuseaux neuro-musculaires." Paris 6, 1992. http://www.theses.fr/1992PA066492.
Повний текст джерелаBerro, Soumaya. "Identification of muscle activation schemes by inverse methods applied on HD-sEMG signals." Electronic Thesis or Diss., Compiègne, 2022. http://www.theses.fr/2022COMP2708.
Повний текст джерелаFast or real-time identification of the spatiotemporal activation of Motor Units (MUs), functional units of the neuromuscular system, is fundamental in applications as prosthetic control and rehabilitation guidance but often dictates expensive computational times. Therefore, the thesis work was devoted to providing an algorithm that enables the real-time identification of MU spatial and temporal activation strategies by applying inverse methods on HD-sEMG (high-density surface electromyogram) signals from a grid placed over the Biceps Brachii (BB). For this purpose, we propose an innovative approach, that involves the use of the classical minimum norm inverse method and a 3D fitting curve interpolation, namely CFB-MNE approach. This method, based on inverse identification (minimum norm estimation) coupled to simulated motor unit action potential (MUAP) dictionary from a recent model and tested on simulations, allowed the real time localization of simulated individual motor units. A robustness analysis (anatomical, physiological, and instrumental modifications) was then performed to verify the efficiency of the proposed algorithm. Finally, the proposed algorithm was tested on MUs with realistic recruitment patterns giving promising results in both spatial and temporal identification. To conclude, a door to future perspectives was opened, according to the obtained promising results, suggesting the use of machine learning and artificial intelligence (AI) to further boost the performance of the proposed algorithm
Perret, Cyril. "La Syllabe comme unité de traitement en production verbale orale et écrite." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2007. http://tel.archives-ouvertes.fr/tel-00270161.
Повний текст джерелаSuite à une tentative de définition de « ce qu'est exactement une syllabe » dans une Introduction, nous avons rapporté des arguments en faveur d'un rôle fonctionnel de cette unité en perception visuelle et auditive.
Le Chapitre I présente une revue de la littérature portant sur la production verbale orale et écrite conceptuellement dirigée (Caramazza & Miceli, 1990 ; Dell, 1986 ; Levelt, Roelofs, & Meyer, 1999). Les différents niveaux de traitement (conceptuel, syntaxique, lexical et moteur) et les propositions concernant les mécanismes de traitement impliqués à chacune de ces étapes sont présentés. Une attention particulière a été portée aux propositions des principaux modèles concernant le rôle de la syllabe dans les processus d'accès lexical et de planification motrice.
Le Chapitre II est consacré à un effet qui est à l'origine d'un vif débat : l'effet d'amorçage syllabique. Ferrand, Segui et Grainger (1996) ont montré que la présentation d'un groupe de segments correspondant à la première syllabe d'un mot (e.g., ba-baleine ; balbalcon) facilite plus la dénomination qu'un groupe de segments plus court (e.g., ba-balcon) ou plus long (bal-baleine). Nous avons essayé de répliquer ce résultat en dénomination orale d'images (Expériences 2a, 2b et 3). Nous avons rapporté des données en faveur de l'hypothèse du recouvrement segmental (Sciller, 1998, 1999, 2000). Nous avons ensuite testé si le temps de présentation de l'amorce (Expérience 4) et le moment de présentation du groupe de segments (Expérience 5) pouvaient expliquer l'absence d'effet d'amorçage syllabique. Là encore, les données sont en accord avec l'hypothèse du recouvrement segmental (Schiller, 1998, 1999, 2000). Nous avons aussi exploré la possibilité d'obtenir cet effet en production verbale écrite (Expériences 1a et 1b).
Dans le Chapitre III, nous avons testé l'hypothèse selon laquelle les latences d'initialisation de mots monosyllabiques devraient être plus courts que celles de mots bisyllabiques, si la syllabe joue un rôle fonctionnel en production verbale orale et écrite. Des études pour les deux modalités ont répondu par la négative (Bachoud-Levi et al., 1998 ; Lambert, 1999 ; Lambert et al., sous presse ; Roelofs, 2002b). Toutefois, Meyer, Roelofs et Levelt, (2003) ont proposé qu'un critère temporel de réponse (Lupker et al., 1997) influence l'instant d'initialisation de la réponse. En conséquence, un effet du nombre de syllabes peut apparaître. Nous avons essayé de répliquer ce résultat en production verbale orale (Expérience 6) et de l'étendre à la production verbale écrite (Expérience 7). Toutefois, nous n'avons pas rapporté de données en faveur de l'hypothèse de Meyer et collaborateurs (2003) pour les deux modalités.
Le Chapitre IV a pour objectif de faire une synthèse des résultats que nous avons obtenus et de proposer des perspectives de recherches.
Duclos, Yann. "Etude des processus spinaux qui préparent à la réalisation d'un mouvement volontaire chez l'homme : implication précoce des motoneurones dans la préparation motrice." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX20683.
Повний текст джерелаThe aim of this work was to analyze the effects of motor preparation on motoneuron (MN) activity. For this purpose, recordings of wrist extensor muscles motor unit activity were combined with time motor preparation paradigms in Human. Changes in the MN tonic discharge were found to occur during preparatory period, i.e. well before it is time to act. These changes were a lengthening of the mean inter-spike interval associated with a decrease of its variability. These data clearly demonstrate that spinal inhibitory mechanisms are activated during motor preparation and suggest the involvement of premotoneuronal interneurons. The modulations of motoneuronal activity induced by the motor preparation are neither specific to the agonist muscle involved in the motor response nor predictive of the performance. It is assumed that the inhibition acting on the MN during the motor preparation constitutes a general braking mechanism serving to prevent premature motor response, whereas the decrease of discharge variability would be a compensatory phenomenon, allowing to produce an efficient steady force in spite of lower motoneuronal activation. The involvement of the motoneuronal level in motor preparation demonstrates that advance information may influence the state of the motor system, including even the most peripheral motor neurons in the spinal cord, which supports the idea that motor preparation involves highly distributed functional processes. In addition, this work led us to argue in favor of the approximate entropy analysis as a suitable method for analyzing spike trains, allowing to detect changes in the regularity of the time-ordered inter-spikes intervals
Biondi, Olivier. "Identification des mécanismes de neuroprotection activés par l’exercice physique dans un modèle souris d’amyotrophie spinale de type 2." Paris 6, 2008. http://www.theses.fr/2008PA066114.
Повний текст джерелаKlass, Malgorzata. "Contribution à l'étude de l'effet du vieillissement sur la fonction neuromusculaire." Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209224.
Повний текст джерелаL’objectif de nos investigations a été d’étudier, chez le sujet humain, les mécanismes responsables de l'altération des performances motrices au cours du vieillissement. La première étude était destinée d’une part, à comparer la diminution maximale de force observée dans les différents régimes de contraction et, d’autre part, à contribuer à la compréhension des mécanismes à l’origine de la meilleure préservation de force pour le régime excentrique. Etant donné que jusqu’à présent, seuls des facteurs musculaires avaient été proposés afin d’expliquer les différences existant en fonction du régime de contraction, nous nous sommes plus particulièrement intéressés à une éventuelle participation de facteurs nerveux.
Dans la seconde étude, nous avons testé de manière indirecte (via l’enregistrement d’activités réflexes) l’efficacité des afférences périphériques au cours du vieillissement. En effet, sous le contrôle de la commande centrale, celles-ci contribuent également à réguler le niveau d’excitabilité des motoneurones. Une moindre efficacité de celles-ci pourrait donc être un facteur supplémentaire responsable de l’altération de la fonction motrice.
Nous avons ensuite analysé (études III et IV) les propriétés contractiles et le comportement des unités motrices lors de contractions lentes et très rapides (contractions balistiques). Cela nous a permis de vérifier s’il existait chez les seniors une relation entre la diminution de force, de sa vitesse d’installation, et la stratégie d’activation des unités motrices.
Enfin, dans l’étude V, nous avons analysé la fatigabilité neuromusculaire chez les seniors, comparativement aux sujets jeunes. Plus spécifiquement, nous avons étudié les contractions concentriques et excentriques maximales fatigantes. La fatigue n’a en effet pas encore été étudiée lors de ces deux types de contraction chez les adultes jeunes et âgés. L’objectif de cette dernière étude était surtout d’analyser la part relative des mécanismes nerveux et musculaires à l’origine de la fatigue ainsi que leur décours dans le temps en fonction de l’âge des sujets.
L’approche méthodologique utilisée nous a permis d’analyser les modifications fonctionnelles du muscle et de ses unités motrices avec l’âge. Un intérêt tout particulier a été porté aux ajustements de la commande nerveuse et à la compréhension des mécanismes sous-jacents. L’ensemble de nos résultats expérimentaux documentent de manière originale l’interaction étroite entre les adaptations nerveuses et musculaires au cours du vieillissement. Plus largement, notre travail doctoral contribue à une meilleure connaissance de la remarquable plasticité du système neuromusculaire chez l’homme.
Résumé en anglais :\
Doctorat en Sciences de la motricité
info:eu-repo/semantics/nonPublished
Pothion, Hugo. "Contribution au développement de stratégies thérapeutiques pour la réparation fonctionnelle de processus neurodégénératifs : apport du peptide PSELT dérivé de la sélénoprotéine T et de cellules souches. Therapeutic benefit of the SELENOT mimetic PSELT in facial nerve regeneration AMPK activation of PGC-1alpha/NRF-1-Dependent SELENOT gene transcription promotes PACAP-induced neuroendocrine cell differentiation through tolerance to oxidative stress Selenoprotein T : an essential oxidoreductase serving as a guardian of endoplasmic reticulum homeostasis." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR030.
Повний текст джерелаPeripheral nervous system has intrinsic regeneration abilities, but motor recovery is insufficient in the most severe cases of lesions. Although surgery remains the “gold standard” therapeutic approach, its efficiency is often limited, and various alternate strategies have been developed such as stem cell-based therapy. However, uncomplete nerve regeneration is also observed, and several approaches aim to improve the potential of these cells. Among them, redox environment modulation using antioxidant molecules is one of the most promising. Selenoprotein T (SELENOT) is an oxidoreductase which is a member of the selenoprotein family, one of the most important family of antioxidant enzymes in the organism. Recently, a mimetic peptide (PSELT) derived from SELENOT has shown a cardioprotective and a neuroprotective effect in a noxious environment. The first part of this study aimed at evaluating the therapeutic potential of PSELT in a facial nerve injury model in rat. In a second part, we asked whether PSELT could improve a stem cells-based therapy using boundary cap (BC) stem cells, a stem cell population located in the dermis which showed a high neurogenic potential. Immediately and 48 hours after the surgery, PSELT was injected into a free femoral vein interposition graft bridging the stumps of an axotomized facial nerve at the level of the exit point of the stylomastoid foramen. Three months later, motor performance of the vibrissae has been analyzed. PSELT significantly improved motor recovery compared to control, and end suture-treated animals. These results were confirmed by electrophysiological and histological analysis which highlighted a better nerve regeneration, an increased myelination and a more specific innervation of the whisker pad in the PSELT-treated group. Combination of PSELT with BC-derived stem cells did not improve further nerve regeneration compared to the PSELT-based therapy alone, both at the clinical and histological levels. Altogether, our results indicate that PSELT offers a therapeutic advantage to treat peripheral nerve lesion compared to surgery and cell therapy approaches, and thus constitutes a valuable candidate for regenerative medicine
Wegrzyk, Jennifer. "Wide-pulse, high-frequency electrical stimulation" in humans : Combined investigations of neural and muscular function using electrophysiological and nuclear magnetic resonance techniques." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4080.
Повний текст джерелаConventional neuromuscular electrical stimulation (CONV) is delivered via surface electrodes at short pulse duration (< 400 μs), low frequencies (≤ 50 Hz) and high current intensities. The motor unit recruitment pattern of CONV, however, is different from the pattern of voluntary contractions (VOL) and leads to a hastened onset of muscle fatigue. The use of wide-pulses (1ms), high frequencies (100 Hz) (WPHF) and low current intensities might approach the natural activation pattern of VOL by enhancing the neural contribution to force production. Previous studies investigating WPHF reported progressive and unexpected force increments ("Extra Forces") despite a constant stimulation intensity which might reflect the more pronounced activation of sensory pathways within the central nervous system. The objective of this thesis was to investigate this "Extra Force" (EF) phenomenon and to evaluate the efficiency of WPHF (1 ms pulse duration at 100 Hz) in terms of metabolic demand and neural contribution to force production in comparison to CONV NMES (0.05 ms pulse duration at 25 Hz) and VOL. Our experiments comprised electrophysiological (EMG) and nuclear magnetic resonance techniques (31P spectroscopy of the muscle, functional imaging of the brain). The findings should be considered in future studies investigating the potential of NMES in a clinical context as a treatment for neuromuscular pathologies
Perdikis, Dionysios. "Functionnal organization of complex behavioral processes." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX22050/document.
Повний текст джерелаBehavioural studies suggest that complex behaviours are multiscale processes, which may be composed of elementary ones (units or primitives). Traditional approaches to cognitive mod-elling generally employ reductionistic (mostly static) representations and computations of simplistic dynamics. The thesis proposes functional architectures to capture the dynamical structure of both functional units and the composite multiscale behaviours. First, a mathe-matical formalism of functional units as low dimensional, structured flows in phase space is introduced (functional modes). Second, additional dynamics (operational signals), which act upon functional modes for complex behaviours to emerge, are classified according to the separation between their characteristic time scale and the one of modes. Then, complexity measures are applied to distinct architectures for a simple composite movement and reveal a trade off between the complexities of functional modes and operational signals, depending on their time scale separation (in support of the control effectiveness of architectures employing non trivial modes). Subsequently, an architecture for serial behaviour (along the example of handwriting) is demonstrated, comprising of functional modes implementing characters, and operational signals much slower (establishing a mode competition and ‘binding’ modes into sequences) or much faster (as meaningful perturbations). All components being coupled, the importance of time scale interactions for behavioural organization is illustrated. Finally, the contributions of modes and signals to the output are recovered, appearing to be possible only through analysis of the output phase flow (i.e., not from trajectories in phase space or time)
Tremblay, Elsa. "Altérations synaptiques à la jonction neuromusculaire dans un modèle murin de sclérose latérale amyotrophique." Thèse, 2015. http://hdl.handle.net/1866/13655.
Повний текст джерелаAmyotrophic lateral sclerosis (ALS) is a fatal late-onset neurodegenerative disease characterized by the progressive loss of upper and lower motor neurons. Denervation of the neuromuscular junction (NMJ) is an early pathological event in various ALS models. Motor units (MU) appear unequally susceptible to denervation, the fast fatigable (FF) MU being the most vulnerable and the slow (S) MU the most resistant. While previous studies in several ALS models have consistently reported alterations in synaptic transmission, their findings have been contradictory. Interestingly, the MU types were not taken into account in these studies, which could explain these discrepancies. We hypothesized that the MU selective vulnerabilities observed in ALS will be associated with MU-specific NMJ alterations throughout the disease course. Using electrophysiology, we studied synaptic transmission of different types of MU in the fast-twitch Extensor Digitorum Longus (EDL; fast fatigable (FF) MU) and the slow-twitch Soleus (SOL; slow (S) and fast fatigue resistant (FR) MU) of the SOD1 mice and their WT littermates. MU types were identified using immunohistochemical labelling of the respective myosine heavy chains. Immunohistochemistry was also performed to assess NMJ integrity by using antibodies against main NMJ components. At a presymptomatic stage (P160), while no morphological alterations of NMJs were seen in both muscles, evoked activity was altered in a MU-specific manner in SOD1 mice. FF MU from SOD1 mice showed a decrease in EPP amplitude and quantal content whereas S MU showed the opposite. Mutant FR MU showed no difference in evoked activity compared to WT. At presymptomatic stage (P380), various morphological alterations were seen in the SOD1 EDL, including denervation, partial innervation and nerve sprouting. Evoked activity was still reduced in FF MU, as well as mEPP frequency. In contrast, at disease onset (P425), synaptic strength of the S MU was now similar to WT MU, whereas FR NMJs showed a decrease in EPP amplitude and quantal content. Surprisingly, paired-pulse facilitation was not altered in any MU type and at any age despite changes in synaptic strength. Taken together, these results reveal that NMJ function is differentially modified according to MU susceptibility in ALS. This study provides insights for a better understanding of NMJ physiology during the illness that is crucial to the development of a proper NMJ-targeted treatment in ALS.