Access Type
Open Access Embargo
Date of Award
January 2024
Degree Type
Dissertation
Degree Name
Ph.D.
Department
Psychology
First Advisor
Noa Ofen
Second Advisor
Ana M. Daugherty
Abstract
Introduction: The hippocampus (Hc) is crucial for memory function across all ages and is comprised of distinct subfields: dentate gyrus (DG), cornu ammonis sectors (CA1-3), and subiculum. Hc subfields support different aspects of memory function across the lifespan and are differentially vulnerable to late-life pathology. Increased knowledge of normative lifespan developmental trajectories of Hc subfield volumes will illuminate their cognitive and health correlates across different ages. Yet, the evidence on change and variability of Hc subfield volumes across the lifespan is sparse. Methods: Here, I conducted a meta-analysis of cross-sectional findings of subfield volumes across ages (n = 48,278 participants, ages = 4–94 years). Using a large longitudinal sample (ages 5-73 years, n=474 at baseline, n=189 at follow-up, mean delay=2.5 years), I further examined lifespan trends in subfield volume changes and age-group differences in change (children, ages 5-18.9 years; middle adults, ages 19-49.9 years; older adults, ages 50-73.9 years). Lastly, I assessed the associations between DG-CA3 volume changes and associative memory within the lifespan sample to gain insight into the nature of associations between volume and memory. Results: The findings of the meta-analysis suggested a nonlinear age trajectory across the lifespan for all the subfields, with a positive between age and DG and CA3-4 volumes across development, followed by a negative age-volume association for all subfields across adulthood. The longitudinal assessment of Hc subfield volumes supported a nonlinear age trajectory CA1-2 and subiculum but a fairly monotonic change pattern for DG-CA3 volumes. The assessment of DG-CA3 in relation to memory further supported a linear relation between the two across the entire lifespan: larger volumes proved advantageous to memory ability across all ages. Notably, there was evidence of individual differences in volume and memory changes with respect to their baseline measures, consistent with the lifespan hypothesis of developmental catch-up. Conclusion: The findings are novel and carry multiple implications for a better understanding of cognitive and health correlates of subfield volumes across the human lifespan.
Recommended Citation
Homayouni, Roya, "Hippocampal Subfield Volumes And Memory Development From Middle Childhood To Late Adulthood: 2-Year Longitudinal Change And Modifiers Of Age Effects" (2024). Wayne State University Dissertations. 3993.
https://digitalcommons.wayne.edu/oa_dissertations/3993
