Made available in DSpace on 2014-06-11T19:31:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-04-18Bitstream added on 2014-06-13T19:01:35Z : No. of bitstreams: 1 silva_mag_dr_jabo.pdf: 749574 bytes, checksum: 8462949c69fe5e74f303ac35d13b37bf (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Objetivou-se avaliar o treinamento realizado com base no limiar de lactato e a resposta hemogasométrica.e eletrolítica arterial e venosa de eqüinos da raça Puro Sangue Árabe submetidos a exercícios testes progressivos. Foram utilizados nove eqüinos, machos ou fêmeas, adultos jovens destreinados. Os animais foram previamente adaptados ao trabalho em esteira rolante e, em seguida, submetidos a exercício teste caracterizado por etapas de velocidades crescentes até que o esforço máximo fosse atingido. Antes, durante e ao final do exercício, bem como após e 30 minutos após o desaquecimento foram colhidas amostras de sangue venoso e arterial para a mensuração de algumas variáveis como Na+, K+, Cai, cr, Lac, Osm, pH, POz, PC02, SatOz, HC03-, Hct, Hb, EB e o AG. O protocolo de treinamento foi estabelecido com base no limiar de lactato (LL) determinado individualmente, sendo este, considerado como sendo o primeiro ponto no qual houve aumento da concentração de lactato superior a 1,0 mmol/L. Os animais foram submetidos a treinamento de resistência por seis semanas, sendo que as sessões tinham duração de 45 mino e eram realizadas três vezes por semana. Após este período, os animais eram sub.metidos, novamente, ao mesmo exercício teste. Os valores de Lac diminuíram enquanto que o pH, a V4 e a Vmáx aumentaram após o treinamento, refletindo a melhora no condicionamento dos animais. As concentrações de Na+, K+, Hb assim como os valores de hematócrito diminuíram após o treinamento em resposta à hipervolemia. Houve aumento do cálcio ionizado pós-treinamento. A POz arterial manteve-se constante, antes e após o treinamento, durante o exercício, não sendo observado hipoxemia. Houve diminuição da PaCOZ paralelamente ao aumento da intensidade do exercício estando associada à hiperventilação... / This work was earried out with the objeetive to evaluate the training released with base in the laetate threshold and the response hemogasometrie and eleetrolytie in venous and arterial blood samples of Thoroughbred Arabian horses. There were utilized nine equines, males or females, young adults fully detrained. The animais previously had been adapted to the work in treadmill and, afie r that, submitted the exereise test eharaeterized by stages of inereasing speeds until the maximum effort was reaehed. Sefore, during and to the end of the exereise, as well as afie r and 30 minutes after the aetivities were finished, samples of both venous and arterial blood were colleeted in order to measure some variables like Na+, K+, Cai, cr, Lae, Osm, pH, P02, PC02, Sat02, HC03-, Het, Hb, ES e o AG. The training protoeol was established on the basis of the laetate threshold (LL) determined individually, being this, eonsidered as being the first point in whieh had inerease of the superior laetate eoneentration 1,0 mmol/L. The animais were submitted to training of resistanee during six weeks, with sessions of 45 minutes, three times a week. Afier this period, the animais were submitted, again, to same type of exereise. The values of Lae had diminished whereas pH, V4 and Vmáx inereased afie r the training, refleeting the improvement in the conditioning of the animais. The eoneentràtions of Na+, K+, Hb as well as the values of hematoerit deereased afier the training in reply to the hypervolemy. Afier-training had increase of ionized ealeium. The P02 arterial remained eonstant, before and afier the training, during the exereise, and hypoxemy wasn't observed. A deereased in PaC02 parallel to the inerease of the intensity of the exereise was assoeiated to the hyperventilation. The instituted training on the basis of the laetate threshold promoted improvement of the physieal eondition and eonsequently, in the bioehemists and hemogasometries variables.

Neste trabalho estudamos os efeitos do exercício forçado diário em esteira rolante e da exposição diária ao estresse (porque o exercício forçado envolve certo grau de estresse) durante 2 ou 8 semanas em diferentes tipos de memória em ratos Wistar machos. Os testes de memória utilizados foram: habituação da exploração em um campo aberto, reconhecimento de objetos, e memória espacial no labirinto aquático de Morris. Após estes primeiros experimentos procuramos verificar também a capacidade do exercício físico em reverter o prejuízo da memória causado pela separação maternal, procedimento que causa um déficit de memória já descrito pela literatura, utilizando, também, o teste de esquiva inibitória. O estresse diário realçou a memória de habituação, os animais aprenderam após 2 mas não após 8 semanas; houve prejuízo de memória curta (MCD) e de longa duração (MLD) na tarefa do reconhecimento em 2 semanas mas somente de MCD após 8 semanas; e não houve nenhum efeito na memória espacial após 2 ou 8 semanas. O protocolo do exercício realçou também a memória de habituação no campo aberto após 2 mas não após 8 semanas; prejudicou MCD e MLD na tarefa do reconhecimento após 2 mas não após 8 semanas; e realçou uma medida importante da aprendizagem espacial após 8 semanas (latência de escape), mas não outras medidas. Em relação ao grupo de animais que foram submetidos à separação maternal verificou-se que o exercício crônico foi capaz de reverter o déficit da MCD e MLD na esquiva inibitória e da MCD no reconhecimento de objetos, mas não teve efeitos sobre o prejuízo da MLD nesta tarefa e sobre a memória espacial testada no Labirinto Aquático de Morris. Portanto, o exercício físico crônico tem uma influência positiva sobre amemória e, adicionalmente, pode ser visto como uma ferramenta terapêutica para reverter determinados déficits de memória. / Here we studied the effects of daily forced exercise in a treadmill and of daily stress (because forced exercise involves a degree of stress) during 2 or 8 weeks on different types of memory in male Wistar rats. The memory tests were: habituation of exploration in an open field, object recognition and spatial memory in Morris water maze. After these experiments we also tried to verify the physical exercise capacity to revert the memory deficit caused by maternal deprivation, procedure that causes a memory deficit already reported, by means of the inhibitory avoidance test. Daily footshock stress enhanced habituation learning after 2 but not after 8 weeks; it hindered both short- (STM) and long-term memory (LTM) of the recognition task after 2 weeks but only STM after 8 weeks; and had no effect on the spatial task after neither 2 or 8 weeks. The exercise protocol also enhanced habituation in the open field after 2 but not 8 weeks; it hindered STM and LTM in the recognition task after 2 but not at 8 weeks; and it enhanced one important measure of spatial learning after 8 weeks (latency to escape) but not other measures. In relation of the animals that was submitted to maternal deprivation we verified that the exercise is capable to revert the deficit of STM and LTM in inhibitory avoidance test and of STM in object recognition test, but don’t have any effect on the prejudice of LTM in object recognition and in spatial memory verify using the Morris water maze test. Thus, the physical exercise had a positive influence on memory and, additionally, it can be seen like one therapeutic strategy to reverts some memory deficits.

Made available in DSpace on 2014-06-11T19:22:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-11-24Bitstream added on 2014-06-13T20:49:29Z : No. of bitstreams: 1 araujo_mb_me_rcla.pdf: 396536 bytes, checksum: 0af725229a672941ea475a288811f915 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / São raros os estudos que associam variáveis metabólicas à intensidade de esforço em ratos. O presente estudo visou analisar os efeitos do treinamento físico em diferentes intensidades sobre biomarcadores de condicionamento aeróbio e de estresse oxidativo em ratos. Foram utilizados ratos da linhagem Wistar (90 dias), que tiveram a transição metabólica aeróbia / anaeróbia determinada pelo teste de Máxima Fase Estável de Lactato (MFEL). O teste para determinação da MFEL foi composto de series de 25 minutos de exercício de corrida em esteira, com diferentes velocidades, fixas em cada série, com intervalos de 48 horas entre elas e coleta de sangue a cada 5 minutos para dosagem de lactato. Em seguida, os ratos foram treinados 40 minutos por dia, 5 dias por semana, na velocidade equivalente à MFEL (TT) ou 25% superior essa (TS), por 8 semanas. Como controles, foram usados ratos mantidos sedentários (S). Ao final, todos os animais foram sacrificados para análise de biomarcadores de ataque oxidativo: produtos que reagem ao ácido tiobarbitúrico – TBARs, do sistema de defesa antioxidante: atividade da enzima catalase e de atividade celular: atividade da enzima fosfatase alcalina em diferentes órgãos: músculo sóleo, fígado, cérebro e sangue assim como aspectos do metabolismo da glicose (captação e oxidação da glicose, síntese de glicogênio e produção de lactato) pelo músculo sóleo. Os principais resultados foram: No inicio do experimento, considerando todo o lote de animais avaliados, a maior parte dos animais (82%) obtiveram a MFEL na velocidade de 25m/min à concentração de 4,38+0,22mmol/L sangüínea de lactato. Ao final do experimento, a maior parte dos ratos treinados na TT (63,63%) apresentou MFEL na velocidade de 25m/min, à concentração sanguínea de lactato 3,10+0,27 mmol/L. A maioria (54,54%) dos treinados TS teve MFEL na velocidade de 25m/min à... / There are few the studies that associate metabolic variables to the intensity of the effort in rats. The present study aim to analyze the effects of physical training in different intensities on biomarkers of aerobic conditioning and of oxidative stress in rats. Wistar rats (80 days) that had the aerobic / anaerobic metabolic transition determined by Maximal Lactate Steady State test (MLSS) were used. The test for determination of MLSS was composed of 25 minutes treadmill running, with different speeds, fixed in each series, with intervals of 48 hours between them and collection of blood every 5 minutes for lactate dosage. Soon afterwards, the rats were trained 40 minutes a day, 5 days a week, in the speed equivalent to MLSS (MT) or 25% above it (AT), for 8 weeks. As controls, rats maintained sedentary (S) were used. At the end, all rats were sacrificed for analysis of biomarkers of oxidative attack: amount of substances that react with thiobarbituric acid - TBARs, of the antioxidant defense system: activity of the enzyme catalase and of cellular activity: activity of the enzyme alkaline phosphatase in different organs: muscle soleus, liver, brain and blood. Aspects of glucose metabolism (glucose uptake and oxidation, glycogen synthesis and lactate production) by the soleus muscle were also evaluated. The main results were: in beginnig of the experiment, considering the whole lot of animals, in most of them (82%) the MLSS was obtained in the speed of 25m/min, to the concentration of 4.38+0.22mmol/L of blood lactate. At the end of the experiment, most of the rats training at the MLSS intensity (63,63%) presented MLSS in the speed of 25m/min, to the concentration of 3.10+0.27 mmol/L of blood lactate. Most (54,54%) of those animals trained above-MLSS they had MLSS in the speed of 25m/min, to the concentration of 3.36+0.62 mmol/L of blood lactate. The sedentary ones (72,72%) showed MLSS in... (Resumo completo, clicar acesso eletrônico abaixo)

Orientador: Maria Alice Rostom de Mello / Banca: Eliane Stevanato / Banca: Cláudio Alexandre Gobatto / Resumo: São raros os estudos que associam variáveis metabólicas à intensidade de esforço em ratos. O presente estudo visou analisar os efeitos do treinamento físico em diferentes intensidades sobre biomarcadores de condicionamento aeróbio e de estresse oxidativo em ratos. Foram utilizados ratos da linhagem Wistar (90 dias), que tiveram a transição metabólica aeróbia / anaeróbia determinada pelo teste de Máxima Fase Estável de Lactato (MFEL). O teste para determinação da MFEL foi composto de series de 25 minutos de exercício de corrida em esteira, com diferentes velocidades, fixas em cada série, com intervalos de 48 horas entre elas e coleta de sangue a cada 5 minutos para dosagem de lactato. Em seguida, os ratos foram treinados 40 minutos por dia, 5 dias por semana, na velocidade equivalente à MFEL (TT) ou 25% superior essa (TS), por 8 semanas. Como controles, foram usados ratos mantidos sedentários (S). Ao final, todos os animais foram sacrificados para análise de biomarcadores de ataque oxidativo: produtos que reagem ao ácido tiobarbitúrico - TBARs, do sistema de defesa antioxidante: atividade da enzima catalase e de atividade celular: atividade da enzima fosfatase alcalina em diferentes órgãos: músculo sóleo, fígado, cérebro e sangue assim como aspectos do metabolismo da glicose (captação e oxidação da glicose, síntese de glicogênio e produção de lactato) pelo músculo sóleo. Os principais resultados foram: No inicio do experimento, considerando todo o lote de animais avaliados, a maior parte dos animais (82%) obtiveram a MFEL na velocidade de 25m/min à concentração de 4,38+0,22mmol/L sangüínea de lactato. Ao final do experimento, a maior parte dos ratos treinados na TT (63,63%) apresentou MFEL na velocidade de 25m/min, à concentração sanguínea de lactato 3,10+0,27 mmol/L. A maioria (54,54%) dos treinados TS teve MFEL na velocidade de 25m/min à ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: There are few the studies that associate metabolic variables to the intensity of the effort in rats. The present study aim to analyze the effects of physical training in different intensities on biomarkers of aerobic conditioning and of oxidative stress in rats. Wistar rats (80 days) that had the aerobic / anaerobic metabolic transition determined by Maximal Lactate Steady State test (MLSS) were used. The test for determination of MLSS was composed of 25 minutes treadmill running, with different speeds, fixed in each series, with intervals of 48 hours between them and collection of blood every 5 minutes for lactate dosage. Soon afterwards, the rats were trained 40 minutes a day, 5 days a week, in the speed equivalent to MLSS (MT) or 25% above it (AT), for 8 weeks. As controls, rats maintained sedentary (S) were used. At the end, all rats were sacrificed for analysis of biomarkers of oxidative attack: amount of substances that react with thiobarbituric acid - TBARs, of the antioxidant defense system: activity of the enzyme catalase and of cellular activity: activity of the enzyme alkaline phosphatase in different organs: muscle soleus, liver, brain and blood. Aspects of glucose metabolism (glucose uptake and oxidation, glycogen synthesis and lactate production) by the soleus muscle were also evaluated. The main results were: in beginnig of the experiment, considering the whole lot of animals, in most of them (82%) the MLSS was obtained in the speed of 25m/min, to the concentration of 4.38+0.22mmol/L of blood lactate. At the end of the experiment, most of the rats training at the MLSS intensity (63,63%) presented MLSS in the speed of 25m/min, to the concentration of 3.10+0.27 mmol/L of blood lactate. Most (54,54%) of those animals trained above-MLSS they had MLSS in the speed of 25m/min, to the concentration of 3.36+0.62 mmol/L of blood lactate. The sedentary ones (72,72%) showed MLSS in... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Orientador: José Corrêa de Lacerda Neto / Banca: Paulo Sérgio Patto dos Santos / Banca: Fabiana Garcia Christovão / Banca: Antonio de Queiroz Neto / Banca: Áureo Evangelista Santana / Resumo: Objetivou-se avaliar o treinamento realizado com base no limiar de lactato e a resposta hemogasométrica.e eletrolítica arterial e venosa de eqüinos da raça Puro Sangue Árabe submetidos a exercícios testes progressivos. Foram utilizados nove eqüinos, machos ou fêmeas, adultos jovens destreinados. Os animais foram previamente adaptados ao trabalho em esteira rolante e, em seguida, submetidos a exercício teste caracterizado por etapas de velocidades crescentes até que o esforço máximo fosse atingido. Antes, durante e ao final do exercício, bem como após e 30 minutos após o desaquecimento foram colhidas amostras de sangue venoso e arterial para a mensuração de algumas variáveis como Na+, K+, Cai, cr, Lac, Osm, pH, POz, PC02, SatOz, HC03-, Hct, Hb, EB e o AG. O protocolo de treinamento foi estabelecido com base no limiar de lactato (LL) determinado individualmente, sendo este, considerado como sendo o primeiro ponto no qual houve aumento da concentração de lactato superior a 1,0 mmol/L. Os animais foram submetidos a treinamento de resistência por seis semanas, sendo que as sessões tinham duração de 45 mino e eram realizadas três vezes por semana. Após este período, os animais eram sub.metidos, novamente, ao mesmo exercício teste. Os valores de Lac diminuíram enquanto que o pH, a V4 e a Vmáx aumentaram após o treinamento, refletindo a melhora no condicionamento dos animais. As concentrações de Na+, K+, Hb assim como os valores de hematócrito diminuíram após o treinamento em resposta à hipervolemia. Houve aumento do cálcio ionizado pós-treinamento. A POz arterial manteve-se constante, antes e após o treinamento, durante o exercício, não sendo observado hipoxemia. Houve diminuição da PaCOZ paralelamente ao aumento da intensidade do exercício estando associada à hiperventilação... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work was earried out with the objeetive to evaluate the training released with base in the laetate threshold and the response hemogasometrie and eleetrolytie in venous and arterial blood samples of Thoroughbred Arabian horses. There were utilized nine equines, males or females, young adults fully detrained. The animais previously had been adapted to the work in treadmill and, afie r that, submitted the exereise test eharaeterized by stages of inereasing speeds until the maximum effort was reaehed. Sefore, during and to the end of the exereise, as well as afie r and 30 minutes after the aetivities were finished, samples of both venous and arterial blood were colleeted in order to measure some variables like Na+, K+, Cai, cr, Lae, Osm, pH, P02, PC02, Sat02, HC03-, Het, Hb, ES e o AG. The training protoeol was established on the basis of the laetate threshold (LL) determined individually, being this, eonsidered as being the first point in whieh had inerease of the superior laetate eoneentration 1,0 mmol/L. The animais were submitted to training of resistanee during six weeks, with sessions of 45 minutes, three times a week. Afier this period, the animais were submitted, again, to same type of exereise. The values of Lae had diminished whereas pH, V4 and Vmáx inereased afie r the training, refleeting the improvement in the conditioning of the animais. The eoneentràtions of Na+, K+, Hb as well as the values of hematoerit deereased afier the training in reply to the hypervolemy. Afier-training had increase of ionized ealeium. The P02 arterial remained eonstant, before and afier the training, during the exereise, and hypoxemy wasn't observed. A deereased in PaC02 parallel to the inerease of the intensity of the exereise was assoeiated to the hyperventilation. The instituted training on the basis of the laetate threshold promoted improvement of the physieal eondition and eonsequently, in the bioehemists and hemogasometries variables. / Doutor

Ao longo dos últimos anos observou-se um aumento no número de idosos no mundo, com isso faz-se necessário buscar terapias que amenizem os danos relacionados e também elucidar os mecanismos envolvidos neste processo. O exercício físico tem sido sugerido como uma ferramenta importante, não farmacológica, para atenuar os déficits relacionados à idade. Ainda, estudos recentes sugerem uma relação entre o processo de envelhecimento cerebral e o desequilíbrio de mecanismos epigenéticos, contudo, estes dados ainda não são conclusivos. Sabe-se que o grau de neuroplasticidade varia com a idade e que as estruturas encefálicas podem responder diferentemente à exposição ao exercício. Estudos demonstram que o córtex pré-frontal está envolvido em funções de alta ordem como atenção, tomada de decisão e memória de trabalho. Portanto, o objetivo deste trabalho foi avaliar os efeitos de diferentes protocolos de exercício físico (sessão única e exercício diário moderado) sobre a modulação de marcadores epigenéticos em córtex pré-frontal de ratos Wistar de 3 e 21 meses de idade. Os animais foram submetidos ao protocolo de sessão única (20 minutos) ou o exercício diário moderado (20 minutos durante 14 dias), 1 hora após a última sessão foram eutanasiados. O córtex pré-frontal foi dissecado e a acetilação da H4, o conteúdo da DNA metiltransferase (DNMT1 e DNMT3b), assim como a atividade da histona metiltransferase H3K27 foram analisadas. Os resultados serão apresentados na versão completa desta dissertação. / Over the past few years the number of elderly people has increased in the world, therefore it is necessary to search therapies that ameliorate age-related deficits as well as elucidate the mechanisms involved in this process. Physical exercise has been suggested as an important non-pharmacological approach to alleviate the age-related decline. Furthermore, recent studies have suggested a relationship between the process of brain aging and imbalance of epigenetic mechanisms, however, these data are not conclusive. It is well described that prefrontal cortex is involved in higher functions like attention, decision making and working memory. Then, the aim of this study was to investigate the effects of two exercise protocols (single session and daily moderate exercise) on the modulation of epigenetic markers in the prefrontal cortex from Wistar rats of 3- and 21- months-old. Animals were submitted to single session protocol (20 minutes) or the daily moderate exercise (20 minutes for 14 days), and 1hour after the last exercise session animals were euthanized. Prefrontal cortex was dissected out and acetylation of H4, the content of DNA methyl transferase (DNMT1 and DNMT3B), as well as histone methyltransferase H3K27 activity were analyzed. Results will be presented in the full version.

abstract: The benefits of exercise have been recommended in typical and other special populations. However, the evidence for persons with Down syndrome (DS) is still limited. This study was aimed at investigating the impact of an acute bout of aerobic exercise intervention on motor performance, executive function and intrinsic motivation in adolescents and young adults with DS. Ten participants with DS were assigned to an exercise group, who walked on a incremental treadmill protocol for 20 minutes. The exercise intensity was achieved at 66% of their predicted maximum heart rate. Another ten participants with DS were assigned to an attentional control group, who watched a video for 20 minutes. Measures of fine manual dexterity (e.g., Purdue Pegboard test), manual force production (e.g., grip strength test), processing speed (e.g., visual choice reaction time test), verbal processing (e.g., verbal fluency test), attention shifting ability (e.g., The Dimensional Card sorting test), and inhibitory control (e.g., Knock and Tap test) were tested pre and post intervention. An intrinsic motivation scale (e.g., enjoyment and effort) was conducted after the intervention. First, results showed participants significantly improved their performance in manual force production and Knock and Tap Test after the exercise intervention. While it has been proposed that exercise increases arousal status, neurotransmitters, or cerebral vasculature, the exact mechanisms in persons with DS are still unknown. However, our results showed that after treadmill walking, motor and cognitive improvements can be found in individuals with DS, even in a single exercise session. In addition, participants reported higher scores in enjoyment after video viewing than exercise, which may a result from musical effect or too much emphasis on external rewards in their early participation in exercise. These may imply that participants had low intrinsic motivation to an active lifestyle. Further, scores in effort were significantly higher after exercise than video viewing, which indicated their capabilities to perceive their physical exertion. However, other motivational regulations (e.g., introjected and identified regulations) have shown the relationship with exercise behavior in this population. Thus, further study should consider divergent motivational factors in order to implement an effective exercise program. / Dissertation/Thesis / Ph.D. Kinesiology 2013

Neste trabalho estudamos os efeitos do exercício forçado diário em esteira rolante e da exposição diária ao estresse (porque o exercício forçado envolve certo grau de estresse) durante 2 ou 8 semanas em diferentes tipos de memória em ratos Wistar machos. Os testes de memória utilizados foram: habituação da exploração em um campo aberto, reconhecimento de objetos, e memória espacial no labirinto aquático de Morris. Após estes primeiros experimentos procuramos verificar também a capacidade do exercício físico em reverter o prejuízo da memória causado pela separação maternal, procedimento que causa um déficit de memória já descrito pela literatura, utilizando, também, o teste de esquiva inibitória. O estresse diário realçou a memória de habituação, os animais aprenderam após 2 mas não após 8 semanas; houve prejuízo de memória curta (MCD) e de longa duração (MLD) na tarefa do reconhecimento em 2 semanas mas somente de MCD após 8 semanas; e não houve nenhum efeito na memória espacial após 2 ou 8 semanas. O protocolo do exercício realçou também a memória de habituação no campo aberto após 2 mas não após 8 semanas; prejudicou MCD e MLD na tarefa do reconhecimento após 2 mas não após 8 semanas; e realçou uma medida importante da aprendizagem espacial após 8 semanas (latência de escape), mas não outras medidas. Em relação ao grupo de animais que foram submetidos à separação maternal verificou-se que o exercício crônico foi capaz de reverter o déficit da MCD e MLD na esquiva inibitória e da MCD no reconhecimento de objetos, mas não teve efeitos sobre o prejuízo da MLD nesta tarefa e sobre a memória espacial testada no Labirinto Aquático de Morris. Portanto, o exercício físico crônico tem uma influência positiva sobre amemória e, adicionalmente, pode ser visto como uma ferramenta terapêutica para reverter determinados déficits de memória. / Here we studied the effects of daily forced exercise in a treadmill and of daily stress (because forced exercise involves a degree of stress) during 2 or 8 weeks on different types of memory in male Wistar rats. The memory tests were: habituation of exploration in an open field, object recognition and spatial memory in Morris water maze. After these experiments we also tried to verify the physical exercise capacity to revert the memory deficit caused by maternal deprivation, procedure that causes a memory deficit already reported, by means of the inhibitory avoidance test. Daily footshock stress enhanced habituation learning after 2 but not after 8 weeks; it hindered both short- (STM) and long-term memory (LTM) of the recognition task after 2 weeks but only STM after 8 weeks; and had no effect on the spatial task after neither 2 or 8 weeks. The exercise protocol also enhanced habituation in the open field after 2 but not 8 weeks; it hindered STM and LTM in the recognition task after 2 but not at 8 weeks; and it enhanced one important measure of spatial learning after 8 weeks (latency to escape) but not other measures. In relation of the animals that was submitted to maternal deprivation we verified that the exercise is capable to revert the deficit of STM and LTM in inhibitory avoidance test and of STM in object recognition test, but don’t have any effect on the prejudice of LTM in object recognition and in spatial memory verify using the Morris water maze test. Thus, the physical exercise had a positive influence on memory and, additionally, it can be seen like one therapeutic strategy to reverts some memory deficits.

La coordination des membres est un élément essentiel pour la marche terrestre chez les mammifères. Les mécanismes neuronaux et biomécaniques s'ajustent pour assurer le maintien d'un équilibre dynamique dans un environnement changeant. Lorsque le système est confronté à une perturbation persistante, la coordination des membres s'adapte. L'adaptation est définie comme un recalibrage du mouvement en réponse à une perturbation persistante ainsi que la présence d'après-effets une fois la perturbation disparue, ce qui indique que le nouveau patron a été entreposé dans le système nerveux central. Chez l'homme, le patron locomoteur s'adapte à une marche prolongée sur un tapis roulant partitionné, où l’une des jambes marche à une vitesse supérieure à l'autre, en rétablissant progressivement la symétrie des variables inter-jambes: périodes de double support et des longueurs des pas, ainsi qu’en réduisant l'amplitude de l'activité musculaire (EMG, électromyographie). L’objectif de notre étude était de déterminer si des chats intacts et des chats ayant subis une lésion complète de la moelle épinière (chat spinalisé) s’adaptent à la marche partitionnée prolongée. Pour caractériser l’adaptation locomotrice chez le chat intact et spinalisé, une prise de données cinématiques et électromyographiques des membres postérieurs a été effectuée chats intacts et les chats spinalisés, les longueurs de pas et les périodes de doubles supports étaient, en moyenne, symétriques, pendant la locomotion sur tapis roulant non-partitionné, et sont devenus asymétriques lors de la locomotion sur tapis roulant partitionné. Ces mesures inter-jambes sont demeurées asymétriques tout au long de la période de marche sur tapis roulant partitionné. Au retour à la marche sur tapis roulant non-partitionné, la symétrie a été immédiatement restaurée sans la présence d’après-effets. Chez les chats intacts, l'amplitude EMG moyenne des extenseurs a augmenté pendant la locomotion sur tapis roulant partitionné et elle est restée augmentée tout au long de cette période, alors que chez les chats spinalisés, l'amplitude EMG des membres postérieurs n'a pas changé. Ces résultats indiquent qu’il n’y a pas d’adaptation locomotrice chez le chat intact et spinalisé, ce qui suggère une importante différence physiologique dans le contrôle de la locomotion entre les chats et les humains lors d’une marche asymétrique prolongée. Par conséquent, nous proposons que la symétrie gauchedroite ne s’avère pas importante pour maintenir un équilibre dynamique pendant la locomotion asymétrique prolongée chez le chat, un quadrupède, comparé à l’humain adulte, un bipède. / Abstract : Coordination of the limbs is an essential component of terrestrial locomotion in mammals. When the system is confronted with persistent perturbations from the environment, the interlimb pattern learns to adapt. Adaptation is defined as a recalibration of the movement in response to a persistent perturbation as well as the presence of after-effects upon removal of the perturbation, indicating storage of the new pattern within the central nervous system. In humans, the pattern adapts to prolonged locomotion on a split-belt treadmill, where one leg steps faster than the other, by gradually restoring the symmetry of interlimb variables (double support periods, step lengths) and by reducing the amplitude of muscle activity (EMG, electromyography). The adaptation is also characterized by a reversal of the asymmetry of interlimb kinematic variables initially observed during the early split-belt period when returning to tied-belt locomotion (i.e. an after-effect). To assess the presence of locomotor adaptation, we measured intralimb (stance durations) and interlimb (double support periods, step lengths) variables bilaterally as well as EMG in the hindlimbs of intact and spinal-transected cats before, during and after 10 mins of split-belt locomotion. In both intact and spinal cats, step lengths and double support periods were, on average, symmetric, during tied-belt locomotion, and became asymmetric during split-belt locomotion. These interlimb variables remained asymmetrical throughout the split-belt period and upon returning to the tied-belt condition, left-right symmetry was immediately restored. In intact cats, the mean EMG amplitude of extensors increased during split-belt locomotion and remained increased throughout the split-belt period, while in spinal cats, hindlimb EMG amplitude did not change. The results indicate a lack of adaptation during prolonged split-belt locomotion in intact and spinal cats, suggesting an important physiological difference in the control of locomotion between cats and humans during prolonged asymmetric stepping. We propose that restoring left-right symmetry is not important to maintain dynamic balance during prolonged asymmetrical locomotion in the cat, a quadruped, as opposed to the adult human, a biped.

The CAREN-Extended system is a fully immersive virtual environment (VE) that can provide stability-challenging scenarios in a safe, controlled manner. Understanding gait biomechanics when stability is challenged is required when developing quantifiable metrics for rehabilitation assessment. The first objective of this thesis was to examine the VE’s technical aspects to ensure data validity and to design a stability-challenging VE scenario. The second and third objectives examined walking speed changes and kinematic strategies when stability was challenged for able-bodied and unilateral transtibial amputees. The results from this thesis demonstrated: 1) understanding VE operating characteristics are important to ensure data validity and to effectively design virtual scenarios; 2) self-paced treadmill mode for VEs with multiple movement scenarios may elicit more natural gait; 3) gait variability and trunk motion measures are useful when quantitatively assessing stability performance for people with transtibial amputations.