Structural and resting‐state MRI detects regional brain differences in young and mid‐age healthy APOE‐e4 carriers compared with non‐APOE‐e4 carriers. (29th February 2016)

• Record Type: Journal Article
• Authors: Dowell, Nicholas G.; Evans, Simon L.; Tofts, Paul S.; King, Sarah L.; Tabet, Naji; Rusted, Jennifer M.
• Is Part Of: NMR in biomedicine. Volume 29:Number 5(2016:May)
• Page Start: 614
• Page End: 624
• Publication Date: 2016-02-29
• Subjects: apolipoprotein E e4 -- cortical thickness -- white matter volume -- resting‐state MRI -- regional brain volume -- neurogenesis; Nuclear magnetic resonance -- Periodicals; Magnetic Resonance Spectroscopy -- Periodicals; 574
• DOI: 10.1002/nbm.3502
• Languages: English
• ISSNs: 0952-3480

Abstract

Abstract : The presence of the e4 allele of the apolipoprotein E ( APOE ) gene is the best‐known genetic risk factor for Alzheimer's disease. In this study, we investigated the link between functional and behavioural differences and regional brain volume and cortical thickness differences in those who carry the e4 allele (e4+) and those who only carry the e3 allele (e3/e3). We studied these genotype populations in two age groups: a young group (average age, 21 years) and a mid‐age group (average age, 50 years). High‐resolution T 1 ‐weighted MRI scans were analysed with Freesurfer to measure regional white matter brain volume and cortical thickness differences between genotype groups at each age. These data were correlated with behavioural findings in the same cohort. Resting‐state MRI was also conducted to identify differences in underlying brain functional connectivity. We found that there was a positive correlation between the thickness of the parahippocampal cortex in young e4+ individuals and performance on an episodic memory task. Young e4+ individuals also showed a positive correlation between white matter volume in the left anterior cingulate and performance on a covert attention task. At mid‐age, e4+ individuals had structural differences relative to e3/e3 individuals in these areas: the parahippocampal cortex was thicker and white matter volume in the left anterior cingulate was greater than in e3/e3 individuals. We discuss the possibility that an over‐engagement with these regions by e4+ individuals in youth may have a neurogenic effect that is observable later in life. The cuneus appears to be an important region for APOE‐driven differences in the brain, with greater functional connectivity among young e3/e3 individuals and greater white matter volume in young e4+ individuals. Copyright © 2016 John Wiley & Sons, Ltd. Abstract : Apolipoprotein E (APOE) is the best‐known risk factor for Alzheimer's disease. In this study, we investigate the behavioural and brain differences between those who carry the e4 allele of APOE (e4+) and those who do not (e4–). In particular, we reveal a correlation between the parahippocampal volume and memory, and between the anterior cingulate volume and covert attention. These brain regions also have a greater volume in e4+ individuals at mid‐age, suggesting that an over‐reliance on these regions in youth may have a neurogenic effect.