Hippocampal Subfield Volumes and Spatial Memory Performance in Older Adults At Risk for Developing Type 2 Diabetes

Older adults at risk for type 2 diabetes (T2D) are more likely to experience accelerated cognitive aging and neurodegeneration due to impaired metabolism in the hippocampus. However, the direct relationship between diabetes risk factors, brain volumes (i.e., grey matter, white matter, hippocampus subfields) and hippocampus-dependent functions (i.e., spatial pattern separation) remains unexplored. To investigate this, 60 older adults at risk for T2D (e.g., higher glycated hemoglobin [A1c]) completed touchscreen-based Trial-Unique Delayed Non-Matching to Location (TUNL) and magnetic resonance imaging (MRI). HippUnfold was utilized to segment the hippocampus from high-resolution, T1-weighted images. Findings indicate a relationship between A1c levels and volumes of the dentate gyrus (DG) and Cornu ammonis (CA) 2. Additionally, TUNL percent correct was correlated with grey matter and distinct hippocampus subfield volumes (i.e., subiculum, CA1, and CA4). Understanding the earliest structural changes in T2D risk allows us to uncover opportune moments to begin interventions aimed at preventing irreversible cognitive deficits.