Grant: Master's Award: Canada Graduate Scholarships

Stress is a prevalent Canadian health concern, and one of the leading contributors to physical and mental health issues. One documented effect of stress is an impact on cognitive processes, such as learning. Consistently, stress has been found to increase the tendency for individuals to rely on habitual learning, by which previously established habits influence future behaviours. Over-reliance on this type of learning resulting from chronic stress has the potential to lead to maladaptive behaviours and poor health outcomes. However, the process by which stress promotes habitual learning shows individual, and importantly, sex based variation. The differences between men and women in stress processing and related behaviours has been partially attributed to women’s variation in ovarian hormones. Interestingly, ample evidence from animal research demonstrates that the estrogen 17-? estradiol (E2), inversely to the effect of stress, tends to reduce the use of habitual learning strategies. However, while the separate effects of estrogens and stress on habitual learning are well understood, to date there is no research in humans that has addressed the possible interplay of these factors. The current proposal aims to investigate the interactive effects of E2 and stress on habitual learning in women through exposing women to acute stress in the early (E2 low) or late (E2 high) follicular phases of their menstrual cycle and observing their learning strategies. The interplay of stress and estrogen may produce different behaviours, and thus health trajectories, in men and women. This proposal will fill an important gap in knowledge and increase our understanding surrounding individual and sex-based variation in learning and the dynamic behavioural impacts of stress.