Orientador: Vera Lucia Messias Fialho Capellini / Resumo: Os estudantes com altas habilidades/superdotação apresentam capacidade intelectual acima da média, grande comprometimento com as tarefas e altos níveis de criatividade. Por conta de suas características, necessitam de programas diferenciados de ensino e aprendizagem e, as atividades de enriquecimento curricular são uma das alternativas educacionais previstas para esses estudantes. Pretendeu-se na presente pesquisa investigar as contribuições das atividades de enriquecimento curricular no desenvolvimento cognitivo, escolar e social de estudantes identificados com altas habilidades/superdotação. Levantou-se a hipótese de que, se essas atividades forem bem estruturadas e organizadas de acordo com os interesses e aptidões dos estudantes, serão capazes de favorecer seu desenvolvimento cognitivo, acadêmico e social. Para testá-la, a pesquisa foi dividida em três estudos. O Estudo 1 buscou descrever as atividades de enriquecimento curricular vivenciadas por estudantes identificados com altas habilidades/superdotação em um projeto de extensão e, também, a percepção dos estudantes, pais e professores sobre elas. Para isso, foram elaborados questionários e protocolos que foram respondidos pelos estudantes, seus pais e professores, a respeito das atividades vivenciadas por eles, após a identificação. O Estudo 2 descreveu e comparou o desempenho cognitivo e acadêmico desses estudantes, antes e depois de frequentarem por pelo menos um ano, atividades de enriquecimento curricular. Utilizou... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Students with giftedness have above average intellectual capacity, great commitment to tasks and high levels of creativity. Because of their characteristics, they need differentiated teaching and learning programs, and curriculum enrichment activities are one of the educational alternatives foreseen for these students. The aim of this research was to investigate the contributions of curriculum enrichment activities to the cognitive, school and social development of students identified with giftedness. The hypothesis was raised that, if these activities are well structured and organized according to the interests and aptitudes of students, they will be able to favor their cognitive, academic and social development. To test it, the research was divided into three studies. Study 1 sought to describe the curriculum enrichment activities experienced by students identified with giftedness in an extension project and the perception of students, parents and teachers about them. To this end, questionnaires and protocols were prepared and answered by students, their parents and teachers, regarding the activities they experienced, after identification. Study 2 described and compared the cognitive and academic performance of these students, before and after attending curriculum enrichment activities for at least one year. Raven's Progressive Color Matrix Test, the Wechsler Intelligence Scale (WISC-IV) and the School Performance Test (TDE) were used. Study 3 sought to describe and compare... (Complete abstract click electronic access below) / Doutor

Un faible apport alimentaire en acides gras polyinsaturés (AGPI) de la série n-3 a été associé à la prévalence des troubles de l'humeur chez l’Homme. Chez les rongeurs, les approches nutritionnelles visant à modéliser une alimentation pauvre en AGPI n-3 ont largement été développées au siècle dernier. En effet, un régime alimentaire carencé en AGPI n-3 sur une ou plusieurs générations induit chez le rongeur des altérations des comportements émotionnels tels que des comportements de type dépressif ou anxieux. Nous avons montré au laboratoire Nutrineuro que des souris nourries avec un régime déficient en AGPI n-3 présentent des niveaux d’AGPI n-3, en particulier l'acide docosahexaénoïque (DHA, un AGPI n-3) plus faible dans le cortex préfrontal (PFC) et dans le noyau accumbens (NAc) par rapport aux souris contrôle. De plus, nous avons pu mettre en évidence qu’une alimentation déficiente en AGPI n-3 est capable de moduler la plasticité synaptique dépendante du système endocannabinoïde (eCB). De fait, la réduction de DHA dans le CPF et le NAc est accompagnée d'une altération de la dépression à long terme (LTD-eCB) et des voies de signalisation dépendantes du système eCB au niveau du CPF (Lafourcade et al., 2011 ; Larrieu et al, 2012). Nos données indiquent que ces altérations sont dues à un découplage entre le récepteur cannabinoïde 1 (CB1R) et la protéine Gi/o. De plus, les souris déficientes en AGPI n-3 présentent des déficits comportementaux dans plusieurs tests évaluant les comportements émotionnels. Afin de mieux comprendre les mécanismes qui sous-tendent la diminution du DHA dans le CPF et les altérations des comportements émotionnels, nous avons étudié la morphologie neuronale dans le CPF et l’axe hypothalamo-hypophysaire (HPA) chez les souris déficientes en AGPI n-3. Nous avons montré que le régime alimentaire déficient en AGPI n-3 induit une atrophie de l’arborisation dendritique dans les neurones pyramidaux du CPF. L'atrophie dendritique est semblable à celle mesurée chez les souris soumises au régime équilibré en AGPI n-3 et soumises à un stress chronique de défaite sociale (CSDS). Aucun effet additionnel du CSDS sur la morphologie neuronale et le comportement émotionnel n’a été observé chez les souris déficientes en AGPI n-3. Nous avons ensuite étudié le rôle de l’axe HPA dans le développement des altérations comportementales et neurobiologiques chez les souris déficientes en AGPI n-3. Ces souris présentent une diminution de l'expression des récepteurs des glucocorticoïdes (GR) dans le CPF associée à une augmentation des taux circulants de corticostérone. Dans leur ensemble, nos résultats montrent qu’un faible apport alimentaire en AGPI n-3 peut modifier la plasticité synaptique dépendante du système eCB ainsi que l’arborisation dendritique des neurones du CPF. Nous avons également pu montrer que l’élévation des niveaux de corticostérone était impliquée dans l’altération des comportements émotionnels observée chez des souris nourries avec un régime déficient en AGPI n-3. / Low dietary intake of n-3 polyunsaturated fatty acids (PUFAs) has been associated with the prevalence of mood disorders in humans. In rodents, nutritional approaches aiming at modeling poor dietary n-3 PUFAs intake have been extensively developed in the last century. As a result, one- or multi-generation dietary n-3 deficiency induces depressive and anxiety-like behaviors. We have shown in the Nutrineuro lab that mice fed with a diet deficient in n-3 PUFAs exhibit decreased n-3 PUFAs levels, especially docosahexaenoic acid (DHA, a n-3 PUFA) levels in the prefrontal cortex (PFC) and in the nucleus accumbens (NAc). We showed that dietary n-3 PUFA is able to modulate endocannabinoid (eCB) dependent plasticity since DHA reduction in PFC and NAc is accompanied with eCB dependent long term depression (eCB-LTD) and eCB signaling impairment in the PFC (Lafourcade et al., 2011; Larrieu et al., 2012). Our data indicate that LTD alteration results from region-specific uncoupling of CB1 receptor from its effector Gi/o protein. In addition, n-3 deficient mice display behavioral deficits in several tests measuring emotional behavior. To further understand the mechanisms underlying DHA decrease in the PFC and emotional behavior alteration, we thoroughly investigated neuronal morphology and hypothalamic-pituitary-adrenal (HPA) axis in n-3 deficient mice. We showed that n-3 deficient diet induced dendritic atrophy in pyramidal neurons within the PFC. The dendritic atrophy was comparable to the one measured in control diet mice submitted to chronic social defeat stress (CSDS). No additional effect of CSDS on both neuronal morphology and emotional behavior was measured in n-3 deficient mice. We therefore investigated the role of the HPA axis deregulation in the development of behavioral and neurobiological alterations of n-3 deficient mice. We found a decreased expression of glucocorticoid receptor (GR) in the PFC of n-3 deficient mice together with increased circulating levels of corticosterone. Collectively, we unraveled one crucial mechanism underlying n-3 deficiency-induced alterations. Our results show that low dietary n-3 PUFAs can alter eCB-dependent plasticity and neuronal dendritic atrophy within the PFC leading to emotional behavior impairment. Importantly, we further demonstrated that corticosterone elevation in n-3 deficient mice was involved in the n-3 deficiency-induced emotional behavior and dendritic arborization alterations.