Name: Abigail Marne

Masters Thesis Proposal Meeting

Date: Friday, March 15th, 2024

Time: 4:00 pm

Location: JS Coon 148 or Virtual, Zoom Meeting Link (Meeting ID: 944 5336 4835)

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: immediately after waking, 30 minutes after waking, then approximately every three hours until 21:00, for a total of 70 measurements for each participant. The proposed study will evaluate how the difference between the peak and the nadir cortisol level in each participants’ circadian rhythms changes across the lifespan as well as how it relates to episodic memory, working memory, processing speed, and overall cognitive performance. Secondarily, this study will attempt to replicate prior findings while strengthening pre-existing beliefs within the field of cortisol circadian research.