Background Obesity and associated metabolic dysregulation are linked to impaired cognitive function and alterations in brain structure, which increases the risk of age-related dementia. Increased glucocorticoid (GC) exposure may be a potential mediator of these negative effects on the brain. Methods and results In paper 1, we tested the relationship between cortisol levels, brain morphology and cognitive function in 200 women and men. Salivary cortisol levels were negatively related to cortical surface areas in prefrontal brain regions in both sexes. In participants with type 2 diabetes, high salivary cortisol levels were associated with lower memory performance. In paper 2, we tested in 70 overweight women the effects on tissue-specific GC metabolism of a Paleolithic diet or a diet following the Nordic nutrition recommendations. The 24-month interventions led to decreased expression of the GC-activating enzyme 11βHSD1 in adipose tissue, interpreted as a normalization of an obesity-related disturbance in GC metabolism. Furthermore, GC metabolism by 5α-reductase increased substantially after 2 years, an unexpected and novel result. The outcomes did not differ by diet. In paper 3, 20 women included in paper 2 were examined with functional magnetic resonance imaging (fMRI) while performing a memory task at baseline and after 6 months. Memory performance improved and functional brain responses increased in the hippocampus. Once again, the results were similar in both diet groups. In paper 4, 24 overweight participants with type 2 diabetes were examined with fMRI, using the same memory test as in paper 3, at baseline and after 12 weeks of intervention with a Paleolithic diet with or without exercise training. Functional brain response increased in the hippocampus, but memory was not improved. The addition of physical exercise did not alter the results. Conclusion Cortisol levels are linked to prefrontal brain structure and, at least in type 2 diabetes, lower memory performance. Furthermore, the dysregulated GC metabolism in obesity can be reversed by long-term diet- induced weight loss. Finally, dietary interventions with associated metabolic improvements alter functional brain responses during memory testing, including increased activation of the hippocampus. Whether these changes are linked to alterations in GC exposure and mediate improved cognition requires further study.

INTRODUÇÃO: A memória autobiográfica é um tipo de memória episódica, que abrange os aspectos perceptuais, afetivos e espaço-temporais de um evento. Tais aspectos são organizados em representações que compõem uma história pessoal, sendo portanto fundamentais para a formação da identidade. Esse tipo de lembrança é uma construção transitória e dinâmica gerada a partir de uma base de conhecimento subjacente e esta base é armazenada em diferentes níveis de especificidade de detalhes. Por possuir grande conteúdo episódico, que é dependente das regiões frontais e temporomediais, áreas cerebrais conhecidas por sofrerem alterações significativas com o avanço da idade, é um sistema de memória que parece apresentar declínio com o avanço da idade. O presente estudo procurou investigar a relação entre a memória autobiográfica e o envelhecimento em 57 voluntários saudáveis, que foram divididos em dois grupos: adultos jovens (18 a 50 anos) e adultos mais velhos (51 a 75 anos). METODOLOGIA: A investigação utilizou uma entrevista de memória autobiográfica constituída de 5 eventos públicos marcantes (flashbulb memories), 4 estímulos de valência (positiva e negativa) e 1 evento importante ocorrido no último ano. As entrevistas foram avaliadas e pontuadas de acordo com sistema de categorização dos detalhes relatados em episódicos e semânticos. Também foi usada uma bateria de testes neuropsicológicos composta por 7 testes agrupados em 5 domínios cognitivos destinados a avaliar respectivamente: velocidade de processamento da informação, memória verbal, memória visual, funções executivas e funcionamento intelectual, para examinar possível déficits nesses domínios e suas correlações com o desempenho na entrevista autobiográfica. O nível de significância foi de p < 0.05. RESULTADOS: Não foram encontradas diferenças significativas entre os dois grupos na avaliação de memória autobiográfica, com sujeitos lembrando-se de quantidades semelhantes de detalhes episódicos. Tanto eventos de valência positiva como negativa foram lembrados com a mesma qualidade. Houve uma tendência a um pior desempenho de pessoas mais velhas para relatar lembranças pessoais recentes (que ocorreram no último ano). O grupo mais velho teve pior desempenho em atividades de velocidade de processamento, flexibilidade mental, controle inibitório, memória episódica verbal e memória visual. Foi observada uma correlação positiva entre o desempenho em tarefa padronizada de memória verbal episódica e a quantidade de detalhes episódicos na entrevista de memória autobiográfica. Houve uma relação inversa entre a quantidade de eventos episódicos relatados e a velocidade de processamento de informações apenas no grupo de adultos jovens. Não foram observadas correlações entre os demais domínios cognitivos e os resultados na atividade de memória autobiográfica. CONCLUSÃO: Os resultados obtidos sugerem que as memórias autobiográficas são mais resistentes aos efeitos do tempo. Eventos que têm importante significado pessoal e grande conteúdo emocional aparentam ficar bem preservados na memória / INTRODUCTION: The autobiographical memory is a kind of episodic memory that covers an event\'s aspects of perception, affection, space and time. These are organized in representations that make up a personal history. Therefore, they are paramount to the creation of identity. This type of memory is a transitory and dynamic construction, generated from a foundation of subjacent knowledge stored in details that are specific on different levels. Because it has a vast episodic content, that is dependent of the frontal and temporal medial regions (areas of the brain known for suffering meaningful changes with the aging process), it is a memory system that apparently shows decline with the aging process. This study sought to investigate the relationship between autobiographical memory and aging in 57 healthy subjects that were divided into two groups: young adults (18 to 50 years old) and seniors (51 to 75 years old). METHOD: The investigation used an autobiographical memory interview made up of 5 memorable public events (flashbulb memories), 4 valence stimuli (positive and negative) and 1 important event that happened in the last year. The interviews were evaluated and scored according to the sorting system of details determined either as episodic or semantic. A battery of neuropsychological tests was also used, it was constituted of 7 tests grouped in 5 cognitive domains destined to evaluate, respectively: processing speed, verbal memory, visual memory, executive functions and intellectual performance, to examine possible deficits in these domains and its correlation to the performance in the autobiographical interview. The level of significance was of p < 0.05. RESULTS: There were no meaningful differences between groups in the evaluation of autobiographical memory. Subjects remembered similar amounts of episodic details. Events of both negative and positive valence were recalled with the same quality. In seniors, a tendency towards a worse performance was found when they were asked to tell recent personal memories (that happened last year). The results demonstrate age-related difficulties in activities of speed processing, mental flexibility, inhibitory control, episodic verbal memory and visual memory. A positive correlation was found between the performance in a standardized episodic verbal memory task and the amount of episodic details in the autobiographical memory interview. There was a reverse relation between the amount of episodic events told and the speed of processing information only in the young adults group. No correlations were found between the other cognitive domains and the results in the autobiographical memory activity. CONCLUSION: The obtained results suggest that autobiographical memories are more resistant to the effects of time. Events that have important personal meaning and great emotional content seem to be well preserved in memory

Transcription and translation of proteins are required for the consolidation of episodic memory. Arc, an effector immediate early gene, has been linked to synaptic plasticity following learning and memory. It is well established that the rodent hippocampus is essential for processing spatial memory, but its role in processing object memory is a point of contention. Using immunohistochemical techniques, hippocampal sections were stained for arc proteins in the CA1 region of the dorsal hippocampus in mice following two variations of the novel object recognition (NOR) task. Results suggest mice that acquired strong object memory showed significant hippocampal activation. In mice that acquired weak object memory, hippocampal activation was not significantly different from controls. Arc expression was also examined in other hippocampal sub-regions, as well as in the perirhinal cortex. These results suggest that the mice must acquire a threshold amount of object information before the hippocampal CA1 region is engaged. / Includes bibliography. / Thesis (M.A.)--Florida Atlantic University, 2015 / FAU Electronic Theses and Dissertations Collection

This master's thesis deals with motivation of volunteers. The theoretical part focuses on the field of volunteering in general and also the field of motivation of volunteers. The empirical part presents results from the research that was conducted to find out what the motivation of volunteers in two non-profit organizations was. Findings were put into context and similarities and differences between the two were found. Research was based on questionnaires distributed to volunteers and in-depth interviews with the workers from both organizations. The interviews revealed the perspective of volunteer motivation from the organizations' side. Analysis of results was followed by recommendations for both organizations to improve their work with volunteers.

INTRODUÇÃO: A memória autobiográfica é um tipo de memória episódica, que abrange os aspectos perceptuais, afetivos e espaço-temporais de um evento. Tais aspectos são organizados em representações que compõem uma história pessoal, sendo portanto fundamentais para a formação da identidade. Esse tipo de lembrança é uma construção transitória e dinâmica gerada a partir de uma base de conhecimento subjacente e esta base é armazenada em diferentes níveis de especificidade de detalhes. Por possuir grande conteúdo episódico, que é dependente das regiões frontais e temporomediais, áreas cerebrais conhecidas por sofrerem alterações significativas com o avanço da idade, é um sistema de memória que parece apresentar declínio com o avanço da idade. O presente estudo procurou investigar a relação entre a memória autobiográfica e o envelhecimento em 57 voluntários saudáveis, que foram divididos em dois grupos: adultos jovens (18 a 50 anos) e adultos mais velhos (51 a 75 anos). METODOLOGIA: A investigação utilizou uma entrevista de memória autobiográfica constituída de 5 eventos públicos marcantes (flashbulb memories), 4 estímulos de valência (positiva e negativa) e 1 evento importante ocorrido no último ano. As entrevistas foram avaliadas e pontuadas de acordo com sistema de categorização dos detalhes relatados em episódicos e semânticos. Também foi usada uma bateria de testes neuropsicológicos composta por 7 testes agrupados em 5 domínios cognitivos destinados a avaliar respectivamente: velocidade de processamento da informação, memória verbal, memória visual, funções executivas e funcionamento intelectual, para examinar possível déficits nesses domínios e suas correlações com o desempenho na entrevista autobiográfica. O nível de significância foi de p < 0.05. RESULTADOS: Não foram encontradas diferenças significativas entre os dois grupos na avaliação de memória autobiográfica, com sujeitos lembrando-se de quantidades semelhantes de detalhes episódicos. Tanto eventos de valência positiva como negativa foram lembrados com a mesma qualidade. Houve uma tendência a um pior desempenho de pessoas mais velhas para relatar lembranças pessoais recentes (que ocorreram no último ano). O grupo mais velho teve pior desempenho em atividades de velocidade de processamento, flexibilidade mental, controle inibitório, memória episódica verbal e memória visual. Foi observada uma correlação positiva entre o desempenho em tarefa padronizada de memória verbal episódica e a quantidade de detalhes episódicos na entrevista de memória autobiográfica. Houve uma relação inversa entre a quantidade de eventos episódicos relatados e a velocidade de processamento de informações apenas no grupo de adultos jovens. Não foram observadas correlações entre os demais domínios cognitivos e os resultados na atividade de memória autobiográfica. CONCLUSÃO: Os resultados obtidos sugerem que as memórias autobiográficas são mais resistentes aos efeitos do tempo. Eventos que têm importante significado pessoal e grande conteúdo emocional aparentam ficar bem preservados na memória / INTRODUCTION: The autobiographical memory is a kind of episodic memory that covers an event\'s aspects of perception, affection, space and time. These are organized in representations that make up a personal history. Therefore, they are paramount to the creation of identity. This type of memory is a transitory and dynamic construction, generated from a foundation of subjacent knowledge stored in details that are specific on different levels. Because it has a vast episodic content, that is dependent of the frontal and temporal medial regions (areas of the brain known for suffering meaningful changes with the aging process), it is a memory system that apparently shows decline with the aging process. This study sought to investigate the relationship between autobiographical memory and aging in 57 healthy subjects that were divided into two groups: young adults (18 to 50 years old) and seniors (51 to 75 years old). METHOD: The investigation used an autobiographical memory interview made up of 5 memorable public events (flashbulb memories), 4 valence stimuli (positive and negative) and 1 important event that happened in the last year. The interviews were evaluated and scored according to the sorting system of details determined either as episodic or semantic. A battery of neuropsychological tests was also used, it was constituted of 7 tests grouped in 5 cognitive domains destined to evaluate, respectively: processing speed, verbal memory, visual memory, executive functions and intellectual performance, to examine possible deficits in these domains and its correlation to the performance in the autobiographical interview. The level of significance was of p < 0.05. RESULTS: There were no meaningful differences between groups in the evaluation of autobiographical memory. Subjects remembered similar amounts of episodic details. Events of both negative and positive valence were recalled with the same quality. In seniors, a tendency towards a worse performance was found when they were asked to tell recent personal memories (that happened last year). The results demonstrate age-related difficulties in activities of speed processing, mental flexibility, inhibitory control, episodic verbal memory and visual memory. A positive correlation was found between the performance in a standardized episodic verbal memory task and the amount of episodic details in the autobiographical memory interview. There was a reverse relation between the amount of episodic events told and the speed of processing information only in the young adults group. No correlations were found between the other cognitive domains and the results in the autobiographical memory activity. CONCLUSION: The obtained results suggest that autobiographical memories are more resistant to the effects of time. Events that have important personal meaning and great emotional content seem to be well preserved in memory

L’objectif général de cette thèse était de tester l’efficacité d’un entraînement exécutif ainsi que de tester les transferts des bénéfices de cet entraînement sur d’autres fonctions cognitives notamment la mémoire épisodique au niveau comportemental et électrophysiologique chez des adultes âgés. Pour cela, des effets test-retest ont été observés lors de la passation d’un même test de façon consécutive. Ainsi, la création de nouveaux tests pour confectionner le programme d’entraînement a été nécessaire pour ne pas avoir ces effets tests re-tests lors de la passation des pré-tests et des post-tests. Les entraînements exécutifs ont permis l’amélioration du fonctionnement exécutif mais aussi l’amélioration de la vitesse de traitement, et ces bénéfices ont permis l’annulation des effets d’âge dans le groupe entraîné sur une fonction exécutive : la mise à jour de la mémoire de travail. De plus, des effets de transfert ont été obtenus sur l’utilisation stratégique lors de l’encodage d’information en mémoire épisodique. Plus précisément, les adultes âgés entraînés utilisaient plus de stratégies d’encodages efficaces (encodage profond de type imagerie mentale ou phrase) après l’entraînement exécutif et l’utilisation de ces stratégies était plus efficace. Au niveau cérébral, l’entraînement exécutif semble engendrer des processus de spécialisation cérébrale se traduisant par une diminution de l’activité cérébrale de certaines zones cérébrales. Ce travail de thèse incite le développement de programmes d’entraînement des fonctions exécutives qui semblent permettre des effets de transfert à des tâches non entraînées et ces bénéfices semblent aussi modifier le fonctionnement cérébral, ce qui suppose un effet plus durable. Ceci confirme l’idée qu’un environnement stimulant cognitivement est en lien avec de bonnes capacités cognitives et contribue à un vieillissement réussi / The main objective of this thesis was to test the efficiency of an executive training program and the transfer effects of this program on other cognitive functions, in particular episodic memory strategies and performance. The present work was based on behavioral and electrophysiological data. Practice effects of executive tests have been first tested in young and older adults. Two tests have been practiced across ten practice sessions, and the results showed that the executive functions scores increased after practice, more for the older adults than for the younger ones. In order to develop an executive training program requiring several different tests, we have created new executive tests. The psychometric validity of these tests has been verified and confirmed. These tests have been used for our executive program. Thus, if training effects appeared following this program, they will not be due to the practice of a unique test. Eight sessions of executive stimulation with our new tests have allowed older adults increasing their executive functioning, measured by tests which were different from those employed in the training program (near transfer effects). Other cognitive functions were also improved, as processing speed and episodic memory. For the first time in the literature, far transfer effect have been found memory strategy efficiency and memory performance. More especially, the older adults trained group used more efficient memory strategies (mental imagery or making sentence with the words to be learnt) after the executive training program, and these strategies were more efficient to recall the words. Thus, the memory performance was increased in this group, in comparison the older adults group who did not participate to the training program. At a cerebral level, the executive training seems to decrease the duration of the cerebral activity for the same memory task. However, these results must to be taken with caution and require further analyses to be interpreted correctly. The results of this thesis encourages the development of training programs for executive functions which allows the transfer effects to untrained tasks. These benefits also appear to modify the brain functioning, which implies a longer lasting benefit effect. This work supports the idea that a cognitively stimulating environment is in line with higher cognitive abilities and contributes to successful aging

Les nombreuses études ayant porté sur le vieillissement cognitif ont très tôt permis de distinguer deux composantes clés de la cognition : une composante de « connaissances » définie comme l’ensemble des connaissances générales acquises tout au long de la vie, et une composante de « contrôle exécutif», défini comme l’ensemble des processus de contrôle et de régulation de l’action. Ces modèles permettent d’avancer l’idée selon laquelle le recours à ces deux composantes évolue de manière différentielle au cours de la vie. De ce fait, l’objectif de ce travail de thèse était d’examiner l’implication de ces deux composantes dans la cognition à différentes périodes de vie mais également de déterminer si l’une ou l’autre de ces composantes pouvaient jouer un rôle de protection contre le vieillissement cognitif. L’ensemble des résultats de ce travail suggère que la composante de « contrôle » serait impliquée de manière particulièrement importante dans la cognition chez les adultes âgés, et que cette même composante pourrait jouer un rôle de modération du fonctionnement cognitif au cours du vieillissement normal / Several studies of cognitive aging allow to distinguish two key components of the cognition: « knowledge » defined as the general knowledge acquired throughout the life, and the « executive control », defined as the set of operations that control and regulate cognitive performance. These models suggest that the recourse to these two components evolves in a differential way during the life. Therefore, the objective of this work was to examine the implication of these two components in the cognition at different periods of life but also to determine whether one or the other of these components could play a protective role against the cognitive aging. Results suggest mainly that « control » is more involved in the cognition in older adults, and that this component moderates age-related effect on cognitive functioning

Les études en neurosciences cognitives ont mis en évidence des phénomènes de neuroréorganisation au cours du vieillissement et des corrélats neuronaux spécifiques à la maturation de l’enfant, lors de la réalisation de tâches de mémoire épisodique. Examiner l’évolution des corrélats neuronaux de la récupération en mémoire et déterminer si les patterns cérébraux spécifiques à l’enfant et à l’adulte âgé sont bénéfiques à la performance mnésique constituaient les objectifs majeurs de ce travail. Les résultats ont mis en évidence que les patterns de neuroréorganisation liés à l’âge (modèle PASA et modèle HAROLD) sont déjà présents chez l’adulte jeune et ne sont donc pas spécifiques au cerveau âgé. En accord avec l’hypothèse de compensation, la neuroréorganisation observée chez les adultes âgés, sous la forme d’un shift frontal, apparait bénéfique à la performance mnésique et est liée à un meilleur fonctionnement exécutif. Enfin, l’activité pariétale et frontale chez l’enfant est associée au processus de familiarité, alors que chez les adultes jeunes l’activité pariétale est liée à la remémoration. Chez les adultes âgés, l’activité frontale est associée au processus de remémoration, suggérant un phénomène compensatoire. / Studies in cognitive neurosciences have highlighted neural reorganization phenomena in aging and specific neural correlates associated with children’s maturation during episodic memory tasks. To examine the evolution of the neural correlates of the memory retrieval and to determine if brain patterns specific to children and older adults are beneficial to the memory performance, were the major objectives of this work. Results showed that age-related neural reorganization patterns (PASA model and HAROLD model) are already present in young adults, therefore they are not specific to the older brains. In agreement with the compensation hypothesis, the neural reorganization observed in older adults, taking the form of a frontal shift, appears to be beneficial to memory performance and associated with a better executive functioning. Finally, frontal and parietal activities in children are associated with the familiarity process, whereas in young adults the parietal activity is related to a recollection process. In older adults, the frontal activity is associated with a recollection process, suggesting a compensatory phenomenon.

<p>In the present thesis, three empirical studies investigate autobiographical odor memory with regard to: (a) whole life-span age distributions, (b) phenomenological experience, (c) semantic processing, and (d) odor imagery. Study I explored potential influences of cue type (words, pictures, odors) on the retrieval of autobiographical memories. The results indicated that odor-evoked events were older than memories evoked by words and pictures. The bump for olfactory evoked information peaked in the first decade of life (<10 years of age), whereas the bump of the word- and picture-evoked age distributions peaked in the second decade (i.e., 11-20 years of age). Also, olfactory evoked events were associated with stronger feelings of being brought back in time. Study II investigated the influence of verbal processing on the retrieval of autobiographical olfactory information. The results revealed that semantic knowledge (i.e., the odor name) affected both the age distribution and phenomenological experience. Also, olfactory memories were associated with a higher emotional arousal. Study III addressed the influences of olfactory imagery on the age distribution and phenomenological experiences. The results showed that events evoked by odor imagery were older than memories evoked by words. No differences in phenomenological experiences were found between the two cue conditions. Based on these findings, it is suggested that (a) memories evoked by olfactory information are older than memories evoked by verbal and visual information, (b) odor memories are more emotional and associated with stronger feelings of being brought back in time, (c) knowledge of an odor’s name produces a shift from a more perceptually to a more conceptually driven retrieval, and that (d) imagined odor cues mimic the age distribution of events evoked by real odors. Overall, the results suggest that memories triggered by the olfactory sensory system are different from memories evoked by verbal or visual information.</p>

This study characterizes the mass transport of ions in two streams in the Great Smoky Mountains National Park, comparing transport between stormflow and baseflow periods. By comparing ion mass transport between these two hydrological conditions, the importance of soil and the governing biogeochemical processes will be underscored. Two water quality monitoring study sites were located on the Middle Prong of the Little Pigeon River and Ramsey Prong within the same basin. These remote sites were equipped with YSI 6920 multi-parameter sonde to record continuous 15-min data of pH, depth, conductivity, turbidity, and temperature. Additionally, ISCO 6712 composite samplers were used to collect stream samples during storm events. Baseflow was collected by grab samples prior to storm events, and stormflow collected by ISCO samplers. Throughfall samples were collected after storm events. All samples were analyzed for pH, ANC, and conductivity using an autotitrator. Inductively coupled plasma spectrometry and ion chromatography were used to determine major cations, trace metals, and anions (Ca2+, Na+, K+, Mg2+, Aln+, Cu, Fe, Mn, Si, Zn, SO42-, NO3-, Cl-, NH4+). Stage-discharge relationships were developed at each site utilizing a combination of field measurements and modeling. Velocity and area field measurements were taken to calculate discharges for mid- to low-flow stages while mid- to upper-flow stages were modeled using RIVER2D and verified with field measurements. Stage-discharge curves and sample ion concentrations were used to compute ion mass transport for a two year period in 2006 through 2008. Differences in mass transport of ions between baseflow and stormflow periods found that greater mass transport of ions, except protons, occurred during baseflow periods. These results indicate that on an annual basis ions are stored from input throughfall sources and released gradually through groundwater flow over time more than rapid interflow transport during storm events. This information illustrates the importance of soils and groundwater storage in the regulation of ion transport and streamwater quality in the Great Smoky Mountains National Park.