Name: Abigail Marne

Masters Thesis Defense Meeting

Date: Thursday, October 10th, 2024

Time: 4:00 pm

Location: JS Coon ​150 or Virtual, Zoom Meeting Link (Meeting ID: 939 2491 3709)

Thesis Chair/Advisor:

Scott Moffat, Ph.D. (Georgia Tech)

Thesis Committee Members:

Thackery Brown, Ph.D. (Georgia Tech)

Paul Verhaeghen Ph.D. (Georgia Tech)

Vasilki Michopoulos Ph.D. (Emory University)

Title: Age Related Cortisol Circadian Changes & Cognition

Abstract: Cortisol, a corticosteroid, is a hormone recognized for its role in acute and chronic stress responses and has been linked to Alzheimer’s disease risk and cognitive decline. The circadian rhythm of cortisol has been widely studied in young people and its daily fluctuations have been well-characterized across repeated studies. However, conclusions regarding cortisol’s age-related circadian rhythm changes and their cognitive implications vary, and this may be due to participant pool or methodological differences across studies. In this study using archival data, participants (Mage = 53.6 years, SD = 16.99, range = 23-71, N = 54, 28 females) provided saliva samples seven times a day for 10 consecutive days. The relationship between the difference between the daily Peak and Nadir cortisol measure (PND) and Age suggested no age-related decline in PND. This study also investigated the relationship between PND and cognitive outcomes. Results indicated that PND was not a significant predictor or Overall Cognitive Performance, Processing Speed, or Episodic Memory, but was a significant predictor of Working Memory. Potential explanations for this outcome are proposed based on previous empirical findings and theoretical models.