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Réseaux de neurones et fonction respiratoire : mécanismes sensorimoteurs à la base du coupage locomotion-respirationGiraudin, Aurore 12 December 2008 (has links)
La respiration est une activité motrice autonome rythmique au cours de laquelle de nombreux muscles se contractent de manière coordonnée afin de produire des mouvements ventilatoires adaptés aux contraintes environnementales et aux exigences de l'organisme. Cette fonction vitale doit être fiable et adaptable à très court terme, c’est pourquoi elle est influencée, entre autres, par un grand nombre d’activités motrices. Par exemple, lors d’exercices physiques, le rythme respiratoire peut se coupler au rythme locomoteur. Les objectifs de ce travail doctoral sont centrés sur l’exploration des mécanismes neurogènes à la base du couplage entre ces deux fonctions motrices chez le rat nouveau-né. Pour une grande partie, cette étude a été réalisée sur préparation isolée in vitro de tronc cérébral-moelle épinière de rat nouveau-né (0 à 3 jours), ce modèle permettant de conserver dans leur intégrité les centres responsables des rythmes respiratoire et locomoteur. Compte tenu de l’accessibilité directe aux réseaux neuronaux, les mécanismes de couplage et d'entraînement respiratoire ont été abordés par des approches combinées électrophysiologique, neuroanatomique, pharmacologique et lésionnelle. Dans ce contexte, un des principaux résultats de ce travail doctoral est le rôle crucial joué par les informations sensorielles en provenance des membres antérieurs et postérieurs dans l'entraînement respiratoire observé lors de séquences locomotrices. Ainsi, les afférences proprioceptives spinales capables de réinitialiser et d'entraîner l’activité des centres respiratoires bulbaires via un relais pontique, établissent également des connexions sur l’ensemble des populations de motoneurones spinaux respiratoires phréniques, intercostaux et abdominaux. / Respiration is an autonomous rhythmic motor activity that requires the coordinated contractions of diverse muscles to produce ventilatory movements adapted to organismal needs. This crucial physiological function must be reliable and adaptable on a short-term basis, and requires coordianted movements with various other motor activities. For instance, respiratory rhythmicity becomes coupled to locomotion during physical exercise. My doctoral work aimed to explore the neurogenic mechanisms underlying the interactions between these two motor functions in the neonatal rat. This work was mainly conducted on isolated in vitro brain stem-spinal cord preparations of newborn rats (0-3 days), an experimental model that allows the maintenance of the still functional respiratory and locomotor CPGs in vitro. Due to the easy access to the neuronal networks in these preparations, locomotor-respiratory coupling and respiratory entrainment mechanisms were investigated by combined electrophysiological, neuroanatomical, pharmacological and lesional approaches. A major finding was the crucial played by sensory information from fore- and hindlimb in respiratory entrainment induced by locomotor rythmicity. Spinal sensory afferents can reset and entrain the activity of the medullary respiratory centres via a pontine relay, as well as making direct connections with the various spinal respiratory motoneuron (phrenic, intercostal and abdominal) populations.
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Hodnocení stability, senzomotoriky a symetrie u fotbalistů po operaci LCA pomocí přístroje MFT S3 / Evaluation of stability, sensorimotor and symmetry of football players after ACL reconstruction by MFT S3 toolOtto, Šimon January 2014 (has links)
Theme: Evaluation of stability, sensorimotor and symmetry of football players after ACL reconstruction by MFT S3 tool. Student: Bc. Simon Otto Supervisor: PhDr. Ales Kaplan, PhD. Aims: The aim of the diploma thesis is evaluation of stability, sensorimotor and symmetry of chosen group of football players (n=4) after ACL injury by MFT S3 check test. Methodology: The level of stability, sensorimotor and symmetry was measured by MFT S3 tool and then evaluated with activities during the recondition season. Results: The study proved that some activities are more or less suitable for development of stability and sensorimotor. The biggest positive effect had special workouts aimed for tight muscles and the knee joint. The lowest values were measured after the run and football trainings when the stability and the sensorimotor were impaired. The values were higher in sagittal plane due the preferable sagittal movement used during the football matches. It is important to realize that the recondition process is needs to be lead individually for every athlete after ACL surgery because there is not any universal methodological procedure. Key words: Stability, sensorimotor, symmetry, injury, knee, ACL, football, recondition.
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Perturbations des processus d’intégration sensori-motrice dans la crampe de l’écrivain : une étude physiopathologique combinant imagerie par résonance magnétique fonctionnelle et électroencéphalographie-haute résolution / Disruption of sensorimotor integration in writer's cramp : a pathophysiological study combining functional magnetic resonance imaging and high-resolution electroencephalographyLangbour, Nicolas 10 December 2012 (has links)
La crampe de l'écrivain est la forme la plus fréquente de dystonies de fonction. Elle se caractérise par l’apparition de contractions musculaires involontaires et soutenues aboutissant à une perturbation sévère de l’écriture. Cette dernière est une tâche motrice séquentielle complexe nécessitant un contrôle continu des informations proprioceptives afin d’adapter la position du membre supérieur et la pression des doigts sur le stylo au cours de l’activité motrice. Dans ce travail de thèse nous avons postulé que l’élément fondamental de la physiopathologie de la crampe de l’écrivain est un trouble de l’intégration sensori-motrice. Pour tester cette hypothèse, nous avons utilisé deux tâches comportementales n’induisant pas de symptôme dystonique. Le sujet devait exécuter une séquence motrice, soit de façon spontanée (tâche SGT), soit sur la base d’une séquence de stimulation tactile précédemment apprise (ST). Les modifications d’activité cérébrale au cours de ces deux tâches ont été étudiées par couplage des techniques d’imagerie par résonance magnétique fonctionnelle (IRMf) et d’électroencéphalographie quantitative (EEGq). Nos résultats suggèrent qu’en l’absence de symptôme dystonique, les patients atteints de crampe de l’écrivain présentent une altération de leur performance motrice dans les deux tâches. Durant l’analyse des informations proprioceptives, l’IRMf montre qu’il existe une diminution du signal Bold au niveau du cortex somesthésique primaire, de l’aire motrice supplémentaire (AMS) et du cortex pariétal. Les données d’EEGq révèlent une diminution de la désynchronisation β (DLEβ) au niveau de l’AMS et celles de la cohérence intra-corticale des perturbations du fonctionnement des réseaux pariéto-prémoteurs. Durant la phase motrice, l’IRMf ne révèle aucune différence inter-groupe, mais l’EEGq montre une augmentation de la DLEβ dans les régions pariétales postérieures pour la situation SGT, associée à une augmentation de cohérence intra-corticale. Après l’exécution du mouvement, des anomalies de synchronisation β (SLEβ) sont également retrouvées dans les deux tâches. Ces données montrent qu’il existe chez les patients présentant une crampe de l’écrivain, des perturbations de l’analyse séquentielle des informations proprioceptives, ainsi que des anomalies de l’intégration sensori-motrice. Elles sont en rapport avec une altération des relations fonctionnelles entre les cortex pariétaux et prémoteurs. Ces éléments expliquent pourquoi ces patients au cours de l’écriture ont des difficultés à élaborer une réponse motrice adaptée sur la base d’information proprioceptive séquentielle. / Writer's cramp is the most frequent form of task-specific dystonia. It is characterized by excessive and inappropriate muscle activation resulting in severe disturbance of writing. Writing is a complex sequential motor task requiring the on-line continuous monitoring of proprioceptive information to adjust the position of the upper limb and finger pressure on the pen. In this experimental work, we postulated that the main feature in the pathophysiology of writer's cramp is a sensorimotor integration disorder. To test this hypothesis, we used two behavioral tasks that does not induce dystonic symptoms. The subject performed a motor sequence, either spontaneously (SGT task), or on the basis of a sequence of proprioceptive stimuli previously presented (ST). Changes in brain activity during both tasks were studied by coupling functional magnetic resonance imaging (fMRI) with quantitative electroencephalography (qEEG). Our results show that writer's cramp patients had impaired motor performances in both tasks whereas they did not exhibit any dystonic symptoms. During the analysis of proprioceptive information, fMRI shows a Bold signal decrease in the primary somatosensory cortex, the supplementary motor area (SMA) and parietal cortex. EEGq data revealed a decrease of β desynchronization (βERD) in SMA and intra-cortical coherence a disruption of the functional connectivity of parieto-premotor networks. During the motor phase, fMRI reveals no between-group difference, but EEGq showed an increase of βERD in the posterior parietal regions for the SGT task associated with an increased intra-cortical coherence. During the post-movement period, abnormal β synchronization (βERS) is also found in both tasks. This data shows that writer's cramp patient exhibited a disruption in the sequential analysis of proprioceptive information, as well as abnormalities in sensorymotor integration during motor planning. These features are related to an alteration of the functional relationships between the parietal and premotor cortices. These phenomenons explain why writer's cramp patient fail to develop an appropriate motor response on the basis of sequential proprioceptive information, as in writing.
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Le lien perception-production en voix chantée : place des représentations motricesLévêque, Yohana 14 December 2012 (has links)
Un nombre croissant d'études révèle combien les processus cérébraux de production et de perception de l'action sont intriqués. En particulier, on sait maintenant que la perception de la parole induit l'activation de représentations motrices articulatoires chez l'auditeur. Dans ce travail, nous explorons la perception de la voix chantée, une action vocale non-linguistique. L'écoute d'une voix chantée provoque-t-elle une activation du système moteur ? Cette activité motrice est-elle plus forte pour la voix que pour un son musical non-biologique ? Ces questions sont abordées en utilisant de façon complémentaire deux protocoles comportementaux, une technique de lésion virtuelle par stimulation magnétique transcrâniale, l'étude des oscillations en EEG et celle de la variabilité métabolique en IRMf. Nos résultats montrent que la perception d'une voix chantée est effectivement associée à une activité du cortex sensorimoteur dans des tâches de répétition et de discrimination. De façon intéressante, les plus mauvais chanteurs ont montré la plus forte résonance motrice. Le système moteur pourrait, par la génération de modèles internes, faciliter le traitement des stimuli ou la préparation de la réponse vocale quand le traitement acoustique seul est insuffisant. L'ensemble des résultats présentés ici suggère que les interactions audiomotrices en perception de la voix humaine sont modulées par la dimension biologique du son et par le niveau d'expertise vocale des auditeurs. / A growing body of research reveals that action production and action perception interact. In particular, it has been shown that speech perception entails articulatory motor representations in the listener. In the present work, we investigate the perception of a singing voice, a stimulus that is not primarily linked to articulatory processes. Does listening to a singing voice induce activity in the motor system? Is this motor activity stronger for a voice than for a non-biological musical sound? Two behavioral tasks, a og virtual lesionfg{} paradigm using TMS, the study of brain oscillations with EEG and an fMRI experiment carried out during my PhD have shed some light on these questions. Our results show that the perception of a singing voice is indeed associated with sensorimotor activity in repetition and discrimination tasks. Interestingly, the poorer singers displayed the stronger motor resonance. The motor system could facilitate the processing of sound or the preparation of the vocal response by internal model generation when the acoustic processing is not effective enough. The set of studies presented here thus suggests that audiomotor interactions in human voice perception are modulated by two factors: the biological dimension of sound and the listeners' vocal expertise. These results suggest new perspectives on our understanding of the auditory-vocal loop in speech and of sound perception in general.
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Senzomotorická stimulace - součást komplexní léčby nemocných chronickou obstrukční plicní nemocí / Sensorimotor training - part of comprehensive treatment of chronic obstructive pulmonary diseaseBezděková, Tereza January 2012 (has links)
The thesis deals with the possibility to influence the values of the lung function in patiens with chronic obstructive pulmonary disease (COPD) after exercise carried out according to the Methodology of sensorimotor training. The thesis contains a summary of theoretical knowledge about the pathophysiologic expresion of COPD, including their consequences not only for the respiratory system, but musculoskeletal system as well. Furthermore the thesis includes the information about the Methodology of sensorimotor training, that was used to influence the posture correction in our research. Methods: The spirometric examination of flow-volume curves monitor the changes prior to and after the exercise according to sensorimotor training in patiens with COPD (mean age 60, 733 ± 11,817). Results: The using of sensorimotor training can provide correction of the position of the whole body, of the chest, and change a chest mobility and in total to set up conditions for more economical muscle activation. This enable the changes in the values of the lung functions in the patiens with COPD, that we measured. Not all changes showed statistically significant change. Conclusion: Using sensorimotor training have an objective effect on the values of the lung function in patiens with COPD.
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Learning to match faces and voicesUnknown Date (has links)
This study examines whether forming a single identity is crucial to learning to bind faces and voices, or if people are equally able to do so without tying this information to an identity. To test this, individuals learned paired faces and voices that were in one of three different conditions: True voice, Gender Matched, or Gender Mismatched conditions. Performance was measured in a training phase as well as a test phase, and results show that participants were able to learn more quickly and have higher overall performance for learning in the True Voice and Gender Matched conditions. During the test phase, performance was almost at chance in the Gender Mismatched condition which may mean that learning in the training phase was simply memorization of the pairings for this condition. Results support the hypothesis that learning to bind faces and voices is a process that involves forming a supramodal identity from multisensory learning. / by Meredith Davidson. / Thesis (M.A.)--Florida Atlantic University, 2010. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2010. Mode of access: World Wide Web.
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Effect before cause: supramodal recalibration of sensorimotor timing.Heron, James, Hanson, James Vincent Michael, Whitaker, David J. January 2009 (has links)
Yes / Background: Our motor actions normally generate sensory events, but how do we know which events were self generated
and which have external causes? Here we use temporal adaptation to investigate the processing stage and generality of our
sensorimotor timing estimates.
Methodology/Principal Findings: Adaptation to artificially-induced delays between action and event can produce a
startling percept¿upon removal of the delay it feels as if the sensory event precedes its causative action. This temporal
recalibration of action and event occurs in a quantitatively similar manner across the sensory modalities. Critically, it is
robust to the replacement of one sense during the adaptation phase with another sense during the test judgment.
Conclusions/Significance: Our findings suggest a high-level, supramodal recalibration mechanism. The effects are well
described by a simple model which attempts to preserve the expected synchrony between action and event, but only when
causality indicates it is reasonable to do so. We further demonstrate that this model successfully characterises related
adaptation data from outside the sensorimotor domain.
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Assistive control of motion in sensorimotor impairments based on functional electrical stimulation / Stimulation électrique fonctionnelle pour l’assistance aux mouvements des membres inférieurs dans des situations de déficiences sensori-motricesSijobert, Benoît 28 September 2018 (has links)
Suite à une lésion (ex: blessure médullaire, accident vasculaire cérébral) ou une maladie neurodégénérative (ex: maladie de Parkinson), le système nerveux central humain peut être sujet à de multiples déficiences sensori-motrices menant à des handicaps plus ou moins lourds au cours du temps.Face aux méthodes thérapeutiques classiques, la stimulation électrique fonctionnelle (SEF) des muscles préservés permet de restaurer le mouvement et de fournir une assistance afin d’améliorer la condition des personnes atteintes et de faciliter leur réadaptation fonctionnelle.De nombreuses problématiques intrinsèques à la complexité du système musculo-squelettique et aux contraintes technologiques rendent néanmoins difficile la démocratisation de solutions de stimulation électro-fonctionnelle en dépit d’avancées majeures dans le domaine.Visant à favoriser l’utilisabilité et l’adaptabilité de telles solutions, cette thèse s’appuie sur un réseau de capteurs/actionneurs génériques embarqués sur le sujet, afin d’utiliser la connaissance issue de l’observation et l’analyse du mouvement pathologique des membres inférieurs pour étudier et valider expérimentalement de nouvelles solutions de commande de la SEF à travers une approche orientée-patient. / The human central nervous system (CNS) can be subject to multiple dysfunctions. Potentially due to physical lesions (e.g.: spinal cord injuries, hemorrhagic or ischemic stroke) or to neurodegenerative disorders (e.g.: Parkinson’s disease), these deficiencies often result in major functional impairments throughout the years.As an alternative to usual therapeutic approaches, functional electrical stimulation (FES) of preserved muscles enables to assist individuals in executing functional movements in order to improve their daily life condition or to help enhancing rehabilitation process.Despite major technological advances in rehabilitation engineering, the complexity of the musculoskeletal system and the technological constraints associated have led to a very slow acceptance of neurorehabilitation technologies.To promote usability and adaptability, several approaches and algorithms were studied through this thesis and were experimentally validated in different clinical and pathological contexts, using low-cost wearable sensors combined to programmable stimulators to assess and control motion through a patient-centered approach.
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Large-Scale Cortical Functional Connectivity Underlying Visuospatial AttentionUnknown Date (has links)
The endogenous, or voluntary, control of visuospatial attention relies upon
interactions within a frontoparietal dorsal attention network (DAN) and this network’s
top-down influence on visual occipital cortex (VOC). While these interactions have been
shown to occur during attention tasks, they are also known to occur to some extent at rest,
but the degree to which task-related interactions reflect either modulation or
reorganization of such ongoing intrinsic interactions is poorly understood. In addition, it
is known that in spatial neglect—a syndrome following unilateral brain lesions in which
patients fail to attend to the contralesional side of space—symptom severity covaries with
disruptions to intrinsic interhemispheric interactions between left and right homologous
regions of the DAN; however, similar covariance with disruptions to intrahemispheric
interactions within the DAN, and between the DAN and VOC, has not been demonstrated.
These issues are addressed herein via the measurement of both undirected and directed
functional connectivity (UFC, DFC) within the DAN and between the DAN and VOC. UFC and DFC were derived from correlations of, and multivariate vector autoregressive
modeling of, fMRI BOLD time-series, respectively. Time-series were recorded from
individuals performing an anticipatory visuospatial attention task and individuals at rest,
as well as from stroke patients either with or without neglect and age-matched healthy
controls. With regard to the first issue, the results show that relative to rest, top-down
DAN-to-VOC influence and within-DAN coupling are elevated during task performance,
but also that intrinsic connectivity patterns are largely preserved during the task. With
regard to the second issue, results show that interhemispheric imbalances of
intrahemispheric UFC and DFC both within the DAN and between the DAN and VOC
strongly correlate with neglect severity, and may co-occur with functional decoupling of
the hemispheres. This work thus demonstrates that the intrinsic functional integrity of the
DAN and its relationship to VOC is crucial for the endogenous control of visuospatial
attention during tasks, and that the compromise of this integrity due to stroke likely plays
a role in producing spatial neglect. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection
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Spatiotemporal brain dynamics of the resting stateUnknown Date (has links)
Traditionally brain function is studied through measuring physiological responses in controlled sensory, motor, and cognitive paradigms. However, even at rest, in the absence of overt goal-directed behavior, collections of cortical regions consistently show temporally coherent activity. In humans, these resting state networks have been shown to greatly overlap with functional architectures present during consciously directed activity, which motivates the interpretation of rest activity as day dreaming, free association, stream of consciousness, and inner rehearsal. In monkeys, it has been shown though that similar coherent fluctuations are present during deep anesthesia when there is no consciousness. These coherent fluctuations have also been characterized on multiple temporal scales ranging from the fast frequency regimes, 1-100 Hz, commonly observed in EEG and MEG recordings, to the ultra-slow regimes, < 0.1 Hz, observed in the Blood Oxygen Level Dependent (BOLD) signal of functi onal magnetic resonance imaging (fMRI). However, the mechanism for their genesis and the origin of the ultra-slow frequency oscillations has not been well understood. Here, we show that comparable resting state networks emerge from a stability analysis of the network dynamics using biologically realistic primate brain connectivity, although anatomical information alone does not identify the network. We specifically demonstrate that noise and time delays via propagation along connecting fibres are essential for the emergence of the coherent fluctuations of the default network. The combination of anatomical structure and time delays creates a spacetime structure in which the neural noise enables the brain to explore various functional configurations representing its dynamic repertoire. / Using a simplified network model comprised of 3 nodes governed by the dynamics of FitzHugh-Nagumo (FHN) oscillators, we systematically study the role of time delay and coupling strength in the Using a simplified network model comprised of 3 nodes governed by the dynamics of FitzHugh-Nagumo (FHN) oscillators, we systematically study the role of time delay and coupling strength in the generation o f the slow coherent fluctuations. We find that these fluctuations in the BOLD signal are significantly correlated with the level of neural synchrony implicating that transient interareal synchronizations are the mechanism causing the emergence of the ultra slow coherent fluctuations in the BOLD signal. / by Young-Ah Rho. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.
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