Brain Networks and Behavior in Aging Females: Impacts of Menopause, Sex Hormones, and Sleep Patterns
Loading...
Date
2022-06-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
With both healthy aging and age-related disease, there are sex differences in brain and behavioral outcomes. Collectively, the literature suggests that females experience more severe aging impacts than males. Emerging evidence attributes this divergence in aging trajectories to the loss of neuroprotective sex hormones with the female transition to menopause. However, the role of menopause in middle-age and older female health is largely understudied. Further, most aging research focuses only on cortical contributions, though the cerebellum may also be a key target. The small body of work considering this uncharted territory generally adopts a gross anatomical method to mapping the cerebellum; thus, regional lobular perspectives are lacking.
Through a series of studies, I interrogated the intrinsic organization of lobular cerebellar networks across female adulthood with respect to menopause, sex hormones, and sleep patterns. In each investigation, I used a unique analytical approach to probe different cerebellar networks at rest. In Chapter 2, I used seed-to-voxel analyses to assess differences in cerebellar-whole brain connectivity as a function of menopausal status, finding that postmenopausal females primarily exhibit reduced cerebellar network connectivity, compared to reproductive females. Using the same sample in Chapter 3, I then shifted my attention to cerebellar-subcortical circuitry using an alternative index of functional network efficiency. In contrast to results from Chapter 2, I did not observe differences in cerebellar-subcortical network efficiency between sexes or reproductive stage groups. Finally, in Chapter 4, I evaluated the impact of hormone-sleep interactions on cerebellar connectivity, emphasizing frontal connections, and behavioral performance. In sum, results from Chapter 4 indicate that the link between sex hormones and sleep habits in aging females predicts distinct connectivity patterns in cerebellar-frontal networks and consistent effects on cognitive/motor performance.
Together, the work included within this dissertation provides converging evidence for the influence of menopause on brain and behavioral sex differences in advanced age, highlighting the resting-state dynamics of lobular cerebellar networks. This insight is important for informing perspectives on the biological underpinnings of sex differences in aging, which may be leveraged to develop treatment strategies for improving quality of later life.
Description
Keywords
Aging, Menopause, Sleep