Recent neuropsychological research has stressed the sensitivity of the Prefrontal Cortex, mostly the Dorsolateral region, in relation to aging (Darowski et al., 2008). Prefrontal Cortex functions, such as Inhibitory Control (IC), are thought to wane steadily after the ages of 60-65 (Craik & Bialystok, 2006). Little is known about what changes occur between the stages of prefrontal optimal performance (i.e., ages 20-25), and the later periods of functional decline. The present study aimed to investigate performance differences between younger (ages 30-40; n=9), middle-aged (ages 50-60; n=10), and older adults (ages 70 and up; n=13), on five tasks of Executive Functions (EFs); specifically, assessing the abilities of problem representation, shifting, updating working memory, inhibition, and integrating valence and rewards into pursuing a goal. It was hypothesized that (a) quantitative age trends differentiating the three groups on the tasks would be found, (b) IC would be particularly targeted by the hypothesized age trends, and (c) the devolution of IC across the adult lifespan would be linear. MANOVA tests with all tasks of EFs representing the Dependent Variables and age serving as the Independent Variable revealed no significant main effect. Follow-up separate ANOVA tests however, suggested a statistically significant difference between the means of Groups 2 and 3 for the Updating Working Memory task, F(2,29)=5.374, p=.010, Scheffe (p=.012) and Bonferroni (p=.010). The contributions of interactions among EFs to the present results, recruitment challenges, and potential age effects are discussed. / Graduate / 0622 / emiliecq@uvic.ca

La plasticité cérébrale donne l’opportunité à chaque individu de maximiser son fonctionnement cognitif via l’adoption de comportements enrichis (i.e., théorie de l’enrichissement cognitif). Suivant cette perspective, nous avons articulé dans le cadre de ce travail doctoral des hypothèses inhérentes au rôle modérateur du style de vie sur le déclin cognitif tout au long de la vie adulte, et avons observé le rôle du sexe dans cette relation. La contribution scientifique de ce travail se manifeste au travers de la création et la validation d’un outil de mesure du style de vie (étude 2), et de deux études observationnelles portant (i) sur l’activité physique (étude 1) et (ii) sur le style de vie global (étude 3). Les résultats de cette thèse mettent en évidence l’existence de différents patterns influant sur le vieillissement cognitif, ainsi qu’un important rôle modérateur du sexe dans la relation entre style de vie et déclin cognitif lié à l’âge. Plus précisément, les résultats montrent que le style de vie global, ainsi que les dimensions incluant les relations sociales, les activités physiques pratiquées à long terme et les autres activités de loisirs, sont efficaces pour freiner le vieillissement cognitif chez les femmes uniquement. Si les sollicitations cognitives ne permettent pas, quant à elles, de ralentir la courbe du déclin cognitif, elles influencent de manière positive les performances cognitives tant chez les femmes que chez les hommes. Ce travail doctoral atteste que le style de vie peut représenter un moyen efficace pour lutter contre les effets délétères liés à l’avancée en âge, et permettre non seulement d’ajouter des années à la vie, mais aussi de la vie aux années. / Cerebral plasticity provides an opportunity for each individual to maximize his/her cognitive performance through the adoption of enriched behaviors (i.e., Cognitive Enrichment Theory). From this perspective, we had articulated work hypotheses inherent to the moderating role of lifestyle on the age-related cognitive decline throughout adult lifespan, and we observed the role of sex in this relationship. The scientific contribution of this work occurred through the creation and validation of a lifestyle questionnaire (study 2) and two observational studies about (i) physical activity (study 1) and (ii) the general lifestyle (study 3). Results of this thesis showed the existence of different models influencing cognitive aging, as well as an important moderating role of sex in the relationship between lifestyle and age-related cognitive decline. More specifically, results highlighted that general lifestyle, as well as dimensions including social relationships, long-term physical activities and other leisure activities, were effective for cognitive aging in women only. While cognitive solicitations did not show to slow down the cognitive decline, they had a positive influence on cognitive performances in both women and men. This PhD demonstrated that lifestyle can be an effective way to combat the deleterious effects of aging and could not only add years to life, but also add life to years.

Perhaps the most important single finding in the field of emotional aging has been that the overall quality of affective experience steadily improves during adulthood and can be maintained into old age. Recent lifespan developmental theories have provided motivation- and experience-based explanations for this phenomenon. These theories suggest that, as individuals grow older, they become increasingly motivated and able to regulate their emotions, which could result in reduced negativity and enhanced positivity. The objective of this paper is to expand existing theories and empirical research on emotional aging by presenting a discrete emotions perspective. To illustrate the usefulness of this approach, we focus on a discussion of the literature examining age differences in anger and sadness. These two negative emotions have typically been subsumed under the singular concept of negative affect. From a discrete emotions perspective, however, they are highly distinct and show multidirectional age differences. We propose that such contrasting age differences in specific negative emotions have important implications for our understanding of long-term patterns of affective well-being across the adult lifespan.