O suporte parcial de peso (SPP) define-se por algum grau de diminuição do peso corporal gerado por um aparato de suspensão, que acomoda as elevações e quedas corporais durante a realização da marcha em esteira. Trata-se de um método frequentemente indicado para indivíduos acometidos por disfunções do movimento, cujo programa de tratamento tenha como objetivo a diminuição da magnitude de cargas nos tecidos, gerando proteção articular e diminuição da dor. Contudo, ainda pouco se sabe sobre as reais repercussões geradas na marcha quando o suporte parcial de peso é utilizado. Desta forma, o presente trabalho teve como objetivo verificar o efeito da velocidade e do nível de suspensão corporal sobre variáveis cinemáticas e eletromiográficas de indivíduos saudáveis. Foram avaliados 49 sujeitos saudáveis, 18 do sexo feminino, 31 do sexo masculino, com idade de 28,7(±6,7), massa corporal de 76,9(±14,9) kg, altura de 173,3(±14,9) cm durante a realização de marcha em esteira sob 3 velocidades diferentes (2,0 Km/h, 4 km/h e velocidade auto selecionada), em 4 níveis de suspensão parcial de peso: 0%, 20%, 50% e 80%. Todos os voluntários passaram pelas 12 condições. Observou-se que, acima de 50% de sustentação em velocidades baixas e auto selecionadas, a cadência diminui gradativamente, e a porcentagem do tempo de balanço aumenta, com diminuição gradativa das amplitudes articulares e picos angulares de quadril, joelho e tornozelo. A atividade eletromiográfica também se mostrou diminuída em todas as fases da marcha para os músculos glúteo médio, reto femoral, vasto lateral, bíceps femoral, tibial anterior e gastrocnêmio lateral. Os resultados sugerem, portanto, que a suspensão influencia diretamente no comportamento da marcha de indivíduos saudáveis diminuindo a solicitação muscular e articular, e provavelmente, diminuindo a solicitação mecânica da tarefa, sem contudo alterar por demais as características principais, o que possibilita a utilização de tal estratégia para a proteção articular e o retorno precoce à locomoção, caso haja esta necessidade / Partial weight support (PWS) is an intervention method that allows a decrease in body weight by a suspension apparatus, which accommodates elevations and body falls during treadmill walking. It is frequently prescribed for individuals with movement disorders whose treatment programs aims to decrease the loads in the tissues, promoting joint protection and pain relieve. However, little is known about the actual repercussions generated in gait when partial weight support is used. Thus, the present study aimed to verify the effect of speed and PWS on kinematic and electromyographic variables of healthy individuals. Forty nine healthy subjects (18 women), with 28.7 (± 6.7) years of age, body mass of 76.9 (± 14.9) kg, height of 173.3 (± 14.9) took part of the study. They walked in a treadmill at 3 different velocities (2.0 km/h, 4 km/h and at a self-selected pace), and under 4 levels of partial weight suspension: 0%, 20%, 50% and 80%. All volunteers went through the 12 conditions. We found that PWS above 50% at low velocities and at self-selected pace the gait cadence decreases, the balance phase increases, articular amplitudes and hip, knee and ankle peaks decrease. Higher PWS induced a decrease in the electromyographic activity in gluteus medius, rectus femoris, vastus lateralis, biceps femoris, tibialis anterior and lateral gastrocnemius muscles in all gait phases. These results suggest that the suspension has a direct influence in the gait behavior of healthy individuals. It decreases muscle and joint demands without changing its main characteristics, allowing the use of this strategy for joint protection and early return to independent locomotion

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« - Comment apprécions-nous la complexité du monde qui nous entoure ?- En bougeant nos yeux !- Pourquoi ?- Parce qu’une perception visuelle efficace (avec une acuité maximale !) nécessite de placer l’image des éléments pertinents du champ visuel au niveau d’une petite partie de notre rétine : la fovéa. » Les saccades oculaires sont les mouvements les plus rapides que peut produire notre organisme et sont malgré tout très précises. Le contrôle de ces mouvements représente un défi pour notre cerveau. En effet, ces saccades sont tellement rapides qu’aucune information visuelle ne peut modifier leur trajectoire en cours d’exécution. Mais alors, de quels moyens dispose notre cerveau pour maintenir ces performances tout au long de notre vie? En cas d’imprécision répétée, des mécanismes vont progressivement modifier l’amplitude de nos saccades oculaires afin d’en rétablir la précision. Cette adaptation saccadique repose sur des modifications centrales plastiques. Ce travail de thèse a comme vocation d’élucider les caractéristiques de l’adaptation saccadique chez l’homme. Des approches complémentaires ont permis d’étudier d’une part, l’adaptation des deux grandes catégories de saccades, réactives et volontaires, et d’autre part, l’adaptation en diminution et en augmentation d’amplitude. Nos données permettent de disséquer les mécanismes d’adaptation saccadique dans leur complexité et de mettre en évidence des structures neuronales indispensables à leur mise en place. Notre travail constitue également le support pour le développement de nouvelles procédures de rééducation, basées sur la plasticité oculomotrice. / “- How can we appreciate the complexity of the surrounding word? - By moving our eyes! - Why? - Because an efficient visual perception (with a maximal acuity!) necessitates placing the image of pertinent element from the visual scene at the level of a small part of our retina: the fovea.” Ocular saccades are the fastest movements our organism can produce and they are also highly precise. The control of these movements is a challenge for our brain. Indeed, these saccades are so fast that no visual information can be used during their execution to modify their trajectory. But then, what means does our brain have to maintain these performances all life long? In case of repeated inaccuracies, some mechanisms will progressively modify the amplitude of our ocular saccades in order to restore accuracy. This saccadic adaptation relies on central plastic modifications. The work of this doctorate has the vocation to elucidate the characteristics of saccadic adaptation in Human. Complimentary approaches allowed to study on one side, the adaptation of the two main saccade categories, reactive saccades and voluntary saccades, and on another side, the adaptation decreasing and increasing saccade amplitude. Our data dissects the complexity of mechanisms underlying saccadic adaptation and highlights the neural substrates necessary for these adaptive changes to take place. Our work constitutes also the basis for the development of new rehabilitation procedures, usingoculomotor plasticity.

Several studies have shown the influence of ovarian hormones on the GABAergic system. As women are naturally exposed to monthly fluctuation of these hormones, it is possible that their response to benzodiazepnes also change over the ovarian cycle. Considering that anxiety disorders are most common in women and therefore they receive more prescriptions for benzodiazepines, this study aimed to evaluate the possible influence of the ovarian cycle of healthy women on the acute effect of diazepam. For that, 40 subjectively healthy women were selected and allocated to two different groups, according to their ovarian cycle phase (follicular or luteal). Both groups were submitted to the Video-Monitored Stroop Color-Word Test (VMSCWT), an experimental model of anxiety, under the influence of diazepam (10 mg) or placebo. Psychological parameters (subjective scales of anxiety) and physiological parameters (heart rate and gastrocnemius electromyogram) were evaluated throughout the test. The results showed that, in the follicular phase, women did not respond to the anxiolytic action of diazepam, although a sedative effect was observed, while in the luteal phase, there was no response to either sedative or anxiolytic actions. As a control of the experimental conditions, a group of 18 men was also submitted to the VMSCWT. The results confirmed that both the anxiogenic test and the administered drug were working as expected, since diazepam managed to prevent the anxiety induced by the test. Therefore, the present findings indicate that the ovarian cycle can alter the effects of the acute administration of diazepam, which can vary from no effect to sedation, without going through anxiolysis / Diversos estudos têm mostrado a influência dos hormônios ovarianos no sistema GABAérgico. Como as mulheres são naturalmente expostas à flutuação destes hormônios, é possível que elas apresentem a resposta a benzodiazepínicos alterada ao longo do ciclo ovariano. Estas observações adquirem um significado ainda maior quando se considera que os transtornos de ansiedade são mais comuns em mulheres e, por isso, elas recebem mais prescrições destas drogas. Sendo assim, o presente estudo teve como objetivo avaliar a possível influência do ciclo ovariano de mulheres saudáveis no efeito agudo do diazepam. Para tanto, 40 mulheres subjetivamente saudáveis foram selecionadas e aleatoriamente alocadas para dois grupos, de acordo com a fase do ciclo ovariano (folicular e lútea). Esses grupos foram submetidos ao Teste de Stroop Monitorado por Vídeo (TSMV), um modelo experimental de ansiedade, sob o efeito de 10 mg de diazepam ou placebo. Parâmetros psicológicos (escalas subjetivas de ansiedade) e parâmetros fisiológicos (freqüência cardíaca e eletromiograma do gastrocnêmio) foram avaliados ao longo do teste. Os resultados mostraram que as mulheres na fase folicular não responderam à ação ansiolítica do diazepam, embora o efeito sedativo tenha sido observado. Já as mulheres na fase lútea não responderam nem à ação ansiolítica, nem a ação sedativa do diazepam. Como controle das condições experimentais, um grupo de 18 homens subjetivamente saudáveis também foi submetido ao TSMV. Os resultados confirmaram que tanto o teste ansiogênico quanto a droga administrada estavam funcionando conforme o esperado, uma vez que o diazepam preveniu a ansiedade eliciada pelo teste neste grupo. Portanto, os resultados sugerem que o ciclo ovariano pode alterar os efeitos da administração aguda de diazepam, sendo que tais efeitos podem variar de nenhum efeito à sedação, sem passar pela ansiólise.

Introduction: Memory is a complex cognitive process formerly linked to mechanisms of brain plasticity that can be estimated in the left dorsolateral prefrontal cortex (DLPFC) using transcranial magnetic stimulation and electroencephalography (TMS-EEG). Also, cortical thickness in the DLPFC may be a potential proxy measure of brain plasticity as previous literature reports a link between better memory and thicker cortex. However, the link between brain plasticity and memory performance as well as DLPFC thickness remains to be clarified. Methods: Intermittent theta burst stimulation (iTBS) probed plasticity-like mechanisms in the left DLPFC in 17 cognitively healthy participants. TMS-EEG recordings were performed before and after sham and active iTBS to quantify plasticity via transcranial magnetic stimulation-evoked potentials (TEPs). Composite memory scores for each domain (verbal episodic, visual episodic and working memory) were obtained using the Cambridge Neuropsychological Test Automated Battery. Anatomical T1 images were acquired by magnetic resonance imaging and processed by open-source software (CIVET) and the Automated Anatomical Labeling atlas to extract cortical thickness of the DLPFC. All statistical analyses (linear mixed model, Tukey's post hoc test and Pearson's correlations) were completed in R Studio. Results: iTBS resulted in increased TEP amplitude P30 (F= 5.239, p = 0.029), as shown by a significant interaction between condition (iTBS, sham) and time (pre- and post-condition). Specifically, Tukey's post hoc test revealed that the P30 increase was near trending significant post-iTBS compared to pre-iTBS for the active condition (p = 0.166) but not for the sham condition (p = 0.294). A trending significant relationship was observed between the magnitude of P30 change post-iTBS and thicker left DLPFC (r = 0.488; p = 0.108). Lastly, no significant relationships between P30 change and memory performance were observed. Conclusion: These preliminary findings suggest there could be a relationship between increased capacity for brain plasticity and a thicker left DLPFC. To further investigate these relationships, we plan to recruit additional cognitively healthy participants. Our preliminary findings support the foundation for future clinical studies in which DLPFC thickness could be explored as a predictive factor for response to plasticity-targeting iTBS treatment.

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In this study, we aimed to determine the levels of cytokines IL-1β, IL-4, IL-10, IFN-γ, MIF and VEGF in tears derived from healthy subjects. We tested cytokines as potential markers of inflammation for their potential use in clinical practice. Having reliable method for measuring cytokine levels in tears would enable an early diagnosis of eye diseases. In two phases, cytokines in tears of healthy individuals were analyzed using Bio-Plex Cytokine Assay (Bio-Rad). We assessed the suitability of methods for diagnostic purposes as well as the suitability of our selected cytokines. Statistically significant positive correlations of cytokines were confirmed: IL-10 with IFN-γ (r = 0,81), MIF with VEGF (r = 0,42 / r = 0,49), IL-1β with IL-10 (r = 0,52), IL-1β with IFN-γ (r = 0,55), IL-1β with VEGF (r = 0,38), IFN-γ with VEGF (r = 0,45) and IL-4 with VEGF (r = 0,48) in healthy subjects in tears. IL-4 (r = -0,37) and IFN-γ (r = -0,42) correlate negatively with age. In healthy individuals, there seem to be no differences with regard to gender, BMI, body fat, time of meal consumption prior to tear collection, eye strain when using a computer, dry eyes. Thus, studied cytokines are suitable for diagnostic purposes. Significant differences in concentrations of four (IL-1β, IL-10, IFN-γ a VEGF) of the five...

De nouvelles modalités de réentrainement sont nécessaires pour les patients présentant une sévère limitation à l’exercice tels que les patients souffrant de broncho-pneumopathie chronique obstructive (BPCO). Le pédalage « excentrique », caractérisé par une meilleure efficience, pourrait permettre à ces patients de se réentrainer plus efficacement. Toutefois, les modalités de prescription et les effets du pédalage excentrique méritent d’être étudiés.Chez le sujet sain, nos résultats ont montré un retard de réactivation parasympathique au décours du pédalage excentrique par rapport au concentrique réalisés à même puissance mécanique, avec une influence de la fréquence de pédalage sur les réponses cardio-respiratoires et autonomes. À même puissance métabolique, le pédalage excentrique se caractérise par un stress cardio-vasculaire et respiratoire plus important que lors du pédalage concentrique, et des réponses neuro-végétatives en faveur d’une activité sympathique plus élevée. La fonction vasculaire est altérée à l’issue du pédalage excentrique. Chez le patient atteint de BPCO, comme chez le sujet sain, le pédalage excentrique a un effet tachypnéisant.Nous pensons que la tension musculaire accrue nécessaire en pédalage excentrique à l’atteinte d’une puissance métabolique équivalente à l’exercice concentrique serait à l’origine d’une plus grande activité sympathique et d’une contrainte hémodynamique périphérique, expliquant l’augmentation de la contrainte cardio-vasculaire en pédalage excentrique. / New exercise modalities are required for patients severely limited during exercise such as chronic obstructive pulmonary disease patients (COPD). Eccentric “cycling”, characterized by better efficiency, could allow COPD patients to train more effectively. Nonetheless, prescription modalities and effects of eccentric cycling deserve to be more studied.In healthy subjects, our results showed a delayed parasympathetic reactivation after eccentric compared to concentric cycling matched for mechanical power, together with an influence of pedalling frequency on autonomic and cardiorespiratory responses. At similar metabolic power, eccentric cycling is characterized by a greater cardiovascular and respiratory stress than during concentric cycling, and altered autonomic nervous systems responses in favour to greater sympathetic activity. Vascular function is altered after eccentric cycling. In COPD patients, as in healthy subjects, eccentric cycling impose tachypneic breathing pattern.We believe that the higher muscle tension during eccentric cycling necessary to reach metabolic power similar to concentric leads to greater sympathetic activity and peripheral hemodynamic constraint, likely explaining the increased constraints on cardiovascular system during eccentric cycling.

La fréquence de l’asthme augmente au Vietnam, mais les moyens de diagnostic et d’évaluation fonctionnelle sont limités. Une étude précédente utilisant la technique des oscillations forcées a montré une différence de résistance des voies aériennes entre enfants français et vietnamiens à l’âge de 10 ans mais pas à 6 ans. Si l’hypothèse d’une différence ethnique significative est correcte, alors des différences semblables devraient aussi exister à l’âge adulte. Pour tester l’hypothèse, une étude par pléthysmographie a été mise en place pour mesurer la résistance des voies aériennes et la résistance spécifique des voies aériennes chez de jeunes adultes sains en France et au Vietnam. Nous avons profité de l’étude pour établir des valeurs de référence pour les volumes pulmonaires dans ces populations. La résistance des voies aériennes est significativement plus grande chez les sujets vietnamiens que chez les caucasiens, mais il n’y a aucune différence de résistance spécifique des voies aériennes. Au final, l’étude ne montre pas de différence de calibre des voies aériennes normalisé pour le volume pulmonaire liée l’ethnie, à l’âge adulte. La taille debout est le facteur prédictif le plus important pour la capacité pulmonaire totale, tandis que l’ethnicité est un facteur important pour la capacité vitale et le rapport du volume résiduel à la capacité pulmonaire totale. Cette étude est la première qui fournit des valeurs de référence pour la résistance des voies aériennes, la résistance spécifique des voies aériennes et les volumes pulmonaires par pléthysmographie chez l’adulte vietnamien. La pléthysmographie a été validée à Hanoi et l’étude a permis la formation d’un nouveau groupe de travail sur le diagnostic et la prise en charge de l’asthme au Vietnam / Despite the increasing prevalence of asthma in Viet Nam, the country has limited means for respiratory function testing. A previous study using the forced oscillation technique suggested lower respiratory resistance between French and Vietnamese children at 10 years but not 6 years of age. If the hypothesis of a significant ethnic difference in airway caliber is correct, then similar differences should exist at adult age. To test the hypothesis, a plethysmographic study was set up to measure airway resistance and specific airway resistance in healthy young adults in France and Viet Nam. We took advantage of the study to provide reference values for lung volume in these populations. Airway resistance is significantly larger in Vietnamese than in Caucasians but there is no difference in specific airway resistance. Altogether the study does not support the consequence of a putative ethnic difference in childhood airway caliber on airway resistance normalized for lung volume at adult age. The standing height is the best predictor of the total lung capacity, while ethnicity is an important predictor of vital capacity and of the residual volume to total lung capacity ratio. This is the first study which provides reference values for airway resistance, specific airway resistance and lung volumes by plethysmography in healthy young Vietnamese adults. Plethysmography was validated in the north of Viet Nam, and the study allowed initiating a young working group on asthma diagnosis in Vietnam