Aging and Cognition in Long-Lived Egyptian Fruit Bats: Behavioral Performance and the Unmet Promise of Microstructural Biomarkers

Abstract: To understand the microstructural underpinnings of cognitive aging resilience in exceptionally long-lived species like the Egyptian fruit bat, we aimed to develop and apply a novel neuroimaging biomarker, Normalized Directional Diffusion Variance (NDDV), to assess brain microstructural integrity and correlate it with epigenetic age (DNAmAge) and cognitive performance. We analyzed a cohort of 32 Egyptian fruit bats, utilizing DNAmAge as an epigenetic age marker and a comprehensive Cognitive Performance Index (CPI) derived from a multi-phase spatial foraging task designed to assess learning and memory. Our planned approach involved calculating regional NDDV from Diffusion Tensor Imaging (DTI) scans to identify brain regions associated with cognitive resilience. However, a critical data limitation emerged during neuroimaging processing: the provided DTI files were 3D instead of the expected 4D, rendering NDDV calculation impossible and precluding all planned microstructural analyses. Consequently, the study pivoted to focus on the relationship between age and cognition. We found no statistically significant relationship between DNAmAge and CPI within our cohort, suggesting a lack of age-related cognitive decline in these bats, potentially reflecting their remarkable longevity. Furthermore, we successfully quantified individual differences in age-adjusted cognitive performance by deriving a Cognitive Resilience Score, highlighting substantial variability in cognitive outcomes irrespective of age. While this study provides valuable behavioral insights into cognitive aging in a non-traditional model, the inability to link these findings to microstructural brain integrity due to fundamental data quality issues underscores the critical importance of robust neuroimaging data in multimodal research.

Subjects:	q-bio.NC; q-bio.QM
Cite as:	PX:2508.00038