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Document Type

Feature Article

Publication Date

Fall 9-1-2009

Publication Title

Washington University Undergraduate Research Digest: WUURD 5(1)

Abstract

Peer Editor: Adrienne Sands; Faculty Mentor: Denise Head

Stress over the lifetime has been shown to negatively impact brain struc- ture and cognition in animal models. In addition, advancing age has been observed to have negative effects on brain structure and function. Lifetime stress may contribute to the observed detrimental effects of aging. Aerobic exercise has been shown to be beneficial for brain structure and cognition. Thus, the primary goals of the current study were to assess the effects of lifetime stress in older adult humans and to examine possible moderation of these effects on brain structure and function in older adults through exercise engagement. MRI-based volumes of the prefrontal cortex, orbitofrontal cortex, hippocampus, and amygdala were obtained for 60 healthy adults aged 55 to 87. Cognitive function was measured through a battery of cognitive tasks measuring immediate memory, working memo- ry, executive functions, and processing speed. Data were also obtained through retrospective questionnaires on lifetime stress and exercise engagement. Smaller brain volumes associated with stress were demon- strated for the oribtofrontal cortex and amygdala. Lower capacity for cog- nitive functions of executive functions and processing speed with a non- significant trend for the hippocampus were also demonstrated. In addition, there was a non-significant trend for participants with higher levels of life- time stress to demonstrate steeper age-related decline in immediate memory. There were non-significant trends for exercise engagement to moderate the effects of stress on orbitofrontal cortex and immediate mem- ory: for individuals with lower amounts of stress those who exercised more evidenced less age effects. The potential impact of exercise in moderating the impacts of stress on brain structure and function clearly warrant fur- ther research as well as exploration of such factors as amount of exercise, a threshold for beneficial exercise effects and personality factors.

From the Washington University Undergraduate Research Digest: WUURD, Volume 5, Issue 1, Fall 2009. Published by the Office of Undergraduate Research.

Henry Biggs, Director of Undergraduate Research and Associate Dean in the College of Arts & Sciences; Joy Zalis Kiefer, Undergraduate Research Coordinator, Co-editor, and Assistant Dean in the College of Arts & Sciences; Kristin Sobotka, Editor.

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