Iron Deposition and Distribution Across the Hippocampus Is Associated with Pattern Separation and Pattern Completion in Older Adults at Risk for Alzheimer's Disease

• DOI: 10.1523/jneurosci.1973-23.2024
• Publication Date: 2024-02-22T18:50:16Z
• Authors: Jing Zhou; Alfie Wearn; Julia Huck; Colleen Hughes; Giulia Baracchini; Jennifer Tremblay...; Judes Poirier; Sylvia Villeneuve; Christine Lucas T...; M. Mallar Chakrav...; Ana M. Daugherty; Claudine J. Gauthier; Gary R. Turner; R. Nathan Spreng
• Keywords: 03 medical and health sciences; 0302 clinical medicine

Elevated iron deposition in the brain has been observed older adult humans and persons with Alzheimer's disease (AD), associated lower cognitive performance. We investigated impact of deposition, its topographical distribution across hippocampal subfields segments (anterior, posterior) measured along longitudinal axis, on episodic memory a sample cognitively unimpaired adults at elevated familial risk for AD ( N = 172, 120 females, 52 males; mean age 68.8 ± 5.4 years). MRI-based quantitative susceptibility maps were acquired to derive estimates deposition. The Mnemonic Similarity Task was used measure pattern separation completion, two hippocampally mediated processes. Greater load higher completion scores, both indicators poorer memory. Examination levels within long axis revealed topographic specificity. Among here, posterior CA1 most robustly negatively fidelity representations. This association remained after controlling volume context normal performance standard neuropsychological measures. These findings reveal that is not uniform hippocampus. Both as well spatial distribution, must be taken into account when examining relationship between AD.