Long-term potentiation (LTP) and depression (LTD) are activity dependent long-lasting changes in synaptic efficacy and have been proposed as mechanisms for learning and memory. Although the exact relationship of LTP and LTD to memory is not known, they do share some properties and mechanisms that relate to memory, such as the strengthening and weakening of synapses. LTP and LTD have been studied extensively in hippocampal brain-slice preparations, due to its relatively organized structure, ease of induction, and its critical function in memory storage. Less work has been done in the neocortex despite the belief that it is heavily involved in the storage of long-term memories. Activity dependent plasticity has also been demonstrated in the basal ganglia in vivo and in vitro, but the results have been somewhat inconsistent. The experiments presented in this thesis explore a novel form of neural plasticity in two excitatory pathways (corticostriatal and thalamocortical) of the basal ganglia motor loop in the intact brain in awake, freely behaving rats. In thalamocortical slice preparations, simultaneous presynaptic stimulation and postsynaptic depolarization can induce L TP in animals prior to the critical period. However the results presented in this thesis show that applied stimulation to the thalamocortical pathway failed to produce either LTP or LTD in the awake freely moving animal.Corticostriatal LTD has been shown in slice preparations following direct tetanic stimulation of the striatum. In the current experiment, cortical stimulation failed to induce LTD although there was an observable decrease in the evoked potential following low-frequency stimulation. Corticostriatal L TP has been shown to depend on the type of stimulation applied. High-frequency and theta burst stimulation produced long-lasting changes in response amplitude in the corticostriatal pathway, with theta burst stimulation appearing to be the more effective stimulation protocol for inducing LTP in both the early and late components. Paired stimulation of the substantia nigra pars compacta and cortex indicated a modulatory action of dopamine on corticostriatal synaptic plasticity. Pairing led to a stable increase in the amplitude of LTP of both early and late components. We also report that a temporal relationship exists in the striatum with respect to the release of nigral dopamine and cortical glutamate. Simultaneous stimulation produced a more robust L TP compared to the two other conditions in which there was an applied stimulation delay to either the corticostriatal or nigrostriatal pathway. The results demonstrate the mechanistic differences, not only between the thalamocortical and corticostriatal pathways, but also slice and anesthetized preparations. The results also emphasize the need for further study on mechanisms of L TP and LTD in the various excitatory and inhibitory pathways of the basal ganglia motor loop. / Thesis / Doctor of Philosophy (PhD)

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Les faibles capacités régénératives intrinsèques du système nerveux central, après la survenue de lésions traumatiques ou l'apparition de maladies neuro-dégénératives, ont orienté les recherches vers des thérapies basées sur l'utilisation de cellules souches dans le but de régénérer le tissu cérébral. Cependant, des limitations éthiques et techniques associées aux cellules souches embryonnaires, fœtales ou neurales chez l'adulte restreignent leur utilisation en clinique humaine. À la recherche d'une source alternative, nous nous sommes intéressés à des cellules souches adultes peu connues, provenant du chorion d'un tissu nerveux périphérique en perpétuel renouvellement : les cellules souches de la lamina propria olfactive, localisée dans la cavité nasale. Ces cellules multipotentes ont été décrites comme un sous-type de cellules souches mésenchymateuses, présentant de fortes capacités prolifératives et neurogéniques. En utilisant un premier modèle murin d'amnésie induit par lésion excito-toxique des hippocampes, nous avons montré que des cellules souches olfactives humaines, greffées dans les zones lésées ou dans le liquide céphalo-rachidien, i) s'installent et adoptent un phénotype neuronal, ii) rétablissent la circulation d'informations au sein des réseaux neuronaux défectueux et iii) permettent une récupération des capacités d'apprentissage et de mémorisation. Suite à ces résultats très encourageants, le premier objectif de cette thèse a été de mieux faire connaître ces cellules souches adultes auprès de la communauté scientifique. / The brain displaying poor regenerative capacities, exogenous stem cell-based therapy has been proposed as an attractive strategy to regenerate cerebral tissue after acute injuries or neurodegenerative disorders. However, ethical and technical issues, associated with embryonic, fetal or adult neural stem cells, limit their use in human medicine. In search of alternative candidates, we focused our attention on adult stem cells, located in a peripheral nervous tissue: the nasal stem cells sited in the olfactory lamina propria. These multipotent stem cells have been characterized as a member of the mesenchymal stem cell superfamily, displaying strong proliferative and neurogenic properties. Recently, using a mouse model of amnesia induced by excito-toxic lesions of hippocampal neurons, we demonstrated that olfactory stem cells, grafted in lesioned areas or into the cerebrospinal fluid, i) migrate and differentiate into neuron-like cells, ii) contribute to the restoration of local neuronal networks and iii) promote recovery of learning and memory abilities. In line with these promising results, the first aim of the current thesis was to promote the use of these adult stem cells by the scientific community. For this purpose, we published an article and a book chapter in which we demonstrated that they are suitable for autologous cell therapy in humans. Using an audiovisual document, we showed that these cells i) can be safely obtained in humans, under local anesthesia, without any loss of smell and ii) are easily and quickly amplifiable in vitro.

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Companies struggle against complex and dynamic conditions in order to survive in their business settings. Being in the knowledge era, learning has been accepted as one of the main sources of sustainable competitive advantage. Organizational learning (OL) is a set of activities to obtain organizational memory (OM) by acquiring, sharing, interpreting, integrating and institutionalizing knowledge. OM is exploited by the companies in strategic decision-making process, which makes OL a critical concept. The major objective of this study is to explore how construction companies create OM and how they exploit this asset in strategic decision-making process. In this context, an interview study is conducted with eight large Turkish construction companies and OM perceptions of each company are presented as case studies. This survey revealed the strengths and weaknesses in terms of OL competence. One of the key outputs is that companies are successful at acquiring and storing knowledge but they are not familiar with decision support systems (DSSs) that benefit from OM. Such systems enable OL by assisting decision makers in processing, assessing, integrating and organizing knowledge. To meet the requirements of the industry, a DSS is proposed to aid construction companies in international market entry decisions. This tool is generated under a software package by adopting case-based reasoning (CBR) as the problem solving approach, which finds solutions to new problems based on the past experiences. The model is developed by the acquisition of past real international project data as input information. The model produces two outputs that are indicators of attractiveness of a project and competitiveness of a company, which are the key decision criteria in international market entry problem.

Existem evidências de que dietas compostas por níveis elevados de lipídeos e/ou car-boidratos contribuem para o desenvolvimento de doenças crônico-degenerativas e de déficit cognitivo. Entretanto, os mecanismos pelos quais a obesidade materna interfere na saúde da prole, especificamente no metabolismo e na memória de longo-prazo, ain-da são pouco claros. O objetivo deste trabalho foi investigar se a obesidade materna interfere no metabolismo e nos comportamentos relacionados à memória de longo-prazo de seus filhotes, e se há um efeito somatório com a exposição à dieta de cafete-ria no decorrer da vida da prole. Ratas foram alimentadas com dieta controle (CON) ou de cafeteria (CAF) desde o desmame até os 210 dias de vida, no desmame de sua pro-le. A partir do desmame, seus filhotes machos foram divididos em 4 grupos (CON-CON, CON-CAF, CAF-CON e CAF-CAF) para que todas as ninhadas ingerissem CON ou CAF, independentemente da dieta materna. As mães foram decapitadas no dia seguin-te ao desmame dos filhotes. Foi decapitada e analisada em tarefas comportamentais metade dos filhotes aos 30 dias de idade e, a outra metade, aos 120 dias. As mães CAF apresentaram maior peso corporal total e de tecido adiposo e maiores concentra-ções circulantes de colesterol total, insulina e leptina do que as mães CON. A ingestão calórica semanal dos filhotes que ingeriram CAF mostrou-se maior do que os que inge-riram CON, independentemente da dieta materna. As ninhadas apresentaram peso cor-poral igual no desmame e aos 30dias, porém aos 120dias, os filhotes que ingeriram CON-CAF tiveram aumento de peso em relação aos filhotes CON, independentemente da dieta materna destes. Porém, os filhotes CAF-CAF tiveram redução do peso corporal em relação aos CON-CAF na idade adulta. Aos 30 e 120 dias, os filhotes que ingeriram CAF apresentaram peso de tecido adiposo maior do que os que ingeriram CON, inde-pendentemente da dieta materna. Aos 30 e 120dias, a trigliceridemia e a colesterolemia estavam iguais entre os grupos, assim como a glicemia aos 30 dias. Porém, aos 120 dias, os filhotes que ingeriram CAF apresentaram hiperglicemia, assim como hiperlepti-nemia e hiperinsulinemia, independentemente da dieta materna. Aos 30 dias, todos os grupos que foram expostos à dieta de cafeteria em alguma etapa da vida apresentaram declínio no desempenho em uma ou nas duas tarefas relacionadas à memória de lon-go-prazo (Reconhecimento de objetos e Esquiva Inibitória step-down). Já aos 120 dias, o grupo CAF-CAF foi o único que mostrou piora no desempenho na tarefa de Reconhe-cimento de Objetos, e todos os grupos mostraram capacidade de aprendizado e memó-ria na tarefa de Esquiva Inibitória step-down. Esses dados sugerem que a dieta materna modula o peso corporal e comportamentos relacionados à memória de longo-prazo dos filhotes e que seus efeitos sofrem influência da dieta pós-natal da prole. Porém, novos estudos são necessários para elucidar os mecanismos envolvidos no desenvolvimento dessas alterações. / There is evidence that diets containing high levels of lipids and / or carbohydrates con-tribute to the development of chronic degenerative diseases and cognitive impairment. However, the mechanisms by which maternal obesity affects health of offspring, specifi-cally in metabolism and long-term memory, are still unclear. The aim of this study was to investigate whether maternal obesity interferes with the metabolism and behavior related to long-term memory of their offspring, and if there is a summation effect with exposure to the cafeteria diet during the life of the offspring. Rats were fed a control diet (CON) or cafeteria (CAF) from weaning to 210 days old at weaning of their offspring. After wean-ing, their male offspring were divided into 4 groups (CON-CON, CON-CAF, CAF and CAF-CON-CAF) for all litters ingest CON or CAF, irrespective of maternal diet. Mothers were decapitated on the day following weaning of pups. Was decapitated and analyzed in behavioral tasks half the pups at 30 days of age and the other half at 120 days. CAF mothers had higher total body weight and adipose tissue and increased circulating con-centrations of total cholesterol, insulin and leptin than mothers CON. The weekly caloric intake of pups that ingested CAF was higher than those who ate CON, regardless of maternal diet. Litters showed body weight equal to weaning and 30days, but the 120dias, puppies who ate CON-CAF had weight gain compared to CON offspring, re-gardless of maternal diet these. However, the pups CAF-CAF had reduced body weight compared to CON-CAF adulthood. At 30 and 120 days, the puppies that ingested CAF showed greater weight of adipose tissue than those who ate CON, irrespective of ma-ternal diet. At 30 and 120dias, blood triglyceride and cholesterol were similar between groups, as well as blood glucose levels at 30 days. However, at 120 days, the puppies that ingested CAF showed hyperglycemia, as hiperlepti-nemia and hyperinsulinemia, irrespective of maternal diet. At 30 days, all groups were exposed to the cafeteria diet at some stage of life show a decline in performance in one or both tasks related to long-term memory (Recognition of objects and Dodge inhibitory step-down). Already at 120 days, the group CAF-CAF was the one who showed deterioration in performance in the task of Object Recognition, and all groups showed learning ability and memory in the inhibitory avoidance task step down. These data suggest that maternal diet modulates body weight and behaviors related to long-term memory of the puppies and their effects are influenced by postnatal diet offspring. However, further studies are needed to eluci-date the mechanisms involved in the development of these changes.

Existem evidências de que dietas compostas por níveis elevados de lipídeos e/ou car-boidratos contribuem para o desenvolvimento de doenças crônico-degenerativas e de déficit cognitivo. Entretanto, os mecanismos pelos quais a obesidade materna interfere na saúde da prole, especificamente no metabolismo e na memória de longo-prazo, ain-da são pouco claros. O objetivo deste trabalho foi investigar se a obesidade materna interfere no metabolismo e nos comportamentos relacionados à memória de longo-prazo de seus filhotes, e se há um efeito somatório com a exposição à dieta de cafete-ria no decorrer da vida da prole. Ratas foram alimentadas com dieta controle (CON) ou de cafeteria (CAF) desde o desmame até os 210 dias de vida, no desmame de sua pro-le. A partir do desmame, seus filhotes machos foram divididos em 4 grupos (CON-CON, CON-CAF, CAF-CON e CAF-CAF) para que todas as ninhadas ingerissem CON ou CAF, independentemente da dieta materna. As mães foram decapitadas no dia seguin-te ao desmame dos filhotes. Foi decapitada e analisada em tarefas comportamentais metade dos filhotes aos 30 dias de idade e, a outra metade, aos 120 dias. As mães CAF apresentaram maior peso corporal total e de tecido adiposo e maiores concentra-ções circulantes de colesterol total, insulina e leptina do que as mães CON. A ingestão calórica semanal dos filhotes que ingeriram CAF mostrou-se maior do que os que inge-riram CON, independentemente da dieta materna. As ninhadas apresentaram peso cor-poral igual no desmame e aos 30dias, porém aos 120dias, os filhotes que ingeriram CON-CAF tiveram aumento de peso em relação aos filhotes CON, independentemente da dieta materna destes. Porém, os filhotes CAF-CAF tiveram redução do peso corporal em relação aos CON-CAF na idade adulta. Aos 30 e 120 dias, os filhotes que ingeriram CAF apresentaram peso de tecido adiposo maior do que os que ingeriram CON, inde-pendentemente da dieta materna. Aos 30 e 120dias, a trigliceridemia e a colesterolemia estavam iguais entre os grupos, assim como a glicemia aos 30 dias. Porém, aos 120 dias, os filhotes que ingeriram CAF apresentaram hiperglicemia, assim como hiperlepti-nemia e hiperinsulinemia, independentemente da dieta materna. Aos 30 dias, todos os grupos que foram expostos à dieta de cafeteria em alguma etapa da vida apresentaram declínio no desempenho em uma ou nas duas tarefas relacionadas à memória de lon-go-prazo (Reconhecimento de objetos e Esquiva Inibitória step-down). Já aos 120 dias, o grupo CAF-CAF foi o único que mostrou piora no desempenho na tarefa de Reconhe-cimento de Objetos, e todos os grupos mostraram capacidade de aprendizado e memó-ria na tarefa de Esquiva Inibitória step-down. Esses dados sugerem que a dieta materna modula o peso corporal e comportamentos relacionados à memória de longo-prazo dos filhotes e que seus efeitos sofrem influência da dieta pós-natal da prole. Porém, novos estudos são necessários para elucidar os mecanismos envolvidos no desenvolvimento dessas alterações. / There is evidence that diets containing high levels of lipids and / or carbohydrates con-tribute to the development of chronic degenerative diseases and cognitive impairment. However, the mechanisms by which maternal obesity affects health of offspring, specifi-cally in metabolism and long-term memory, are still unclear. The aim of this study was to investigate whether maternal obesity interferes with the metabolism and behavior related to long-term memory of their offspring, and if there is a summation effect with exposure to the cafeteria diet during the life of the offspring. Rats were fed a control diet (CON) or cafeteria (CAF) from weaning to 210 days old at weaning of their offspring. After wean-ing, their male offspring were divided into 4 groups (CON-CON, CON-CAF, CAF and CAF-CON-CAF) for all litters ingest CON or CAF, irrespective of maternal diet. Mothers were decapitated on the day following weaning of pups. Was decapitated and analyzed in behavioral tasks half the pups at 30 days of age and the other half at 120 days. CAF mothers had higher total body weight and adipose tissue and increased circulating con-centrations of total cholesterol, insulin and leptin than mothers CON. The weekly caloric intake of pups that ingested CAF was higher than those who ate CON, regardless of maternal diet. Litters showed body weight equal to weaning and 30days, but the 120dias, puppies who ate CON-CAF had weight gain compared to CON offspring, re-gardless of maternal diet these. However, the pups CAF-CAF had reduced body weight compared to CON-CAF adulthood. At 30 and 120 days, the puppies that ingested CAF showed greater weight of adipose tissue than those who ate CON, irrespective of ma-ternal diet. At 30 and 120dias, blood triglyceride and cholesterol were similar between groups, as well as blood glucose levels at 30 days. However, at 120 days, the puppies that ingested CAF showed hyperglycemia, as hiperlepti-nemia and hyperinsulinemia, irrespective of maternal diet. At 30 days, all groups were exposed to the cafeteria diet at some stage of life show a decline in performance in one or both tasks related to long-term memory (Recognition of objects and Dodge inhibitory step-down). Already at 120 days, the group CAF-CAF was the one who showed deterioration in performance in the task of Object Recognition, and all groups showed learning ability and memory in the inhibitory avoidance task step down. These data suggest that maternal diet modulates body weight and behaviors related to long-term memory of the puppies and their effects are influenced by postnatal diet offspring. However, further studies are needed to eluci-date the mechanisms involved in the development of these changes.