Journal Article

DZNE-2025-00560

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Differential effects of aging, Alzheimer's pathology, and APOE4 on longitudinal functional connectivity and episodic memory in older adults.

Fischer, L. (First author)DZNE* ; Adams, J. N. ; Molloy, E. N.DZNE* ; Vockert, N.DZNE* ; Tremblay-Mercier, J. ; Remz, J. ; Pichet Binette, A. ; Villeneuve, S. ; Maass, A. (Last author)DZNE* ; Group, P. R. (Collaboration Author)

2025
BioMed Central London

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Please use a persistent id in citations: doi:10.1186/s13195-025-01742-6

Abstract: Both aging and Alzheimer's disease (AD) affect brain networks, with early disruptions occurring in regions involved in episodic memory. Few studies have, however, focused on distinguishing region-specific effects of AD-biomarker negative 'normal' aging and early amyloid- and tau pathology on functional connectivity. Further, longitudinal studies combining imaging, biomarkers, and cognition are rare.We assessed resting-state functional connectivity (rsFC) strength and graph measures in the episodic memory network including the medial temporal lobe (MTL), posteromedial cortex (PMC), and medial prefrontal cortex alongside cognition over two years. For this preregistered study, we included 100 older adults who were amyloid- and tau-negative using CSF and PET measurements to investigate 'normal' aging, and 70 older adults who had longitudinal CSF data available to investigate functional changes related to early AD pathology. All participants were cognitively unimpaired older adults from the PREVENT-AD cohort. We used region of interest (ROI)-to-ROI bivariate correlations, graph analysis, and multiple regression models.In the amyloid- and tau-negative sample, rsFC strength within PMC, between parahippocampal cortex and inferomedial precuneus, and between posterior hippocampus and inferomedial precuneus decreased over time. Additionally, we observed a longitudinal decrease in global efficiency. Further, there was a steeper longitudinal decrease in rsFC and global efficiency with higher baseline age particularly of parahippocampal-gyrus regions. Further, lower rsFC strength within PMC was associated with poorer longitudinal episodic memory performance. In the sample with available CSF data, a steeper increase in rsFC between anterior hippocampus and superior precuneus was related to higher baseline AD pathology. Higher MTL-PMC rsFC strength was differentially associated with episodic memory trajectories depending on APOE4 genotype.Our findings suggest differential effects of aging and AD pathology. Hypoconnectivity within PMC was related to aging and cognitive decline. MTL-PMC hyperconnectivity was related to early AD pathology and cognitive decline in APOE4 carriers. Future studies should investigate more diverse samples, nonetheless, our approach allowed us to identify longitudinal functional changes related to aging and early AD pathology, enhancing cross-sectional research. Hyperconnectivity has been proposed as a mechanism related to early AD pathology before, we now contribute specific functional connections to focus on in future research.

Keyword(s): Humans (MeSH) ; Memory, Episodic (MeSH) ; Male (MeSH) ; Female (MeSH) ; Aged (MeSH) ; Alzheimer Disease: pathology (MeSH) ; Alzheimer Disease: diagnostic imaging (MeSH) ; Alzheimer Disease: genetics (MeSH) ; Alzheimer Disease: physiopathology (MeSH) ; Alzheimer Disease: psychology (MeSH) ; Aging: pathology (MeSH) ; Aging: psychology (MeSH) ; Apolipoprotein E4: genetics (MeSH) ; Longitudinal Studies (MeSH) ; Positron-Emission Tomography (MeSH) ; Brain: diagnostic imaging (MeSH) ; Brain: pathology (MeSH) ; Brain: physiopathology (MeSH) ; Magnetic Resonance Imaging (MeSH) ; Aged, 80 and over (MeSH) ; Middle Aged (MeSH) ; Neural Pathways: physiopathology (MeSH) ; Neural Pathways: diagnostic imaging (MeSH) ; tau Proteins: cerebrospinal fluid (MeSH) ; APOE ; Aging ; Alzheimer’s disease ; Episodic memory ; FMRI ; Functional connectivity ; Apolipoprotein E4 ; tau Proteins

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Contributing Institute(s):

1. Multimodal Neuroimaging (AG Maaß)

Research Program(s):

1. 353 - Clinical and Health Care Research (POF4-353) (POF4-353)

Appears in the scientific report 2025

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Database coverage:
; ; ; ; Article Processing Charges ; Clarivate Analytics Master Journal List ; Current Contents - Clinical Medicine ; DOAJ Seal ; Ebsco Academic Search ; Essential Science Indicators ; Fees ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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Linked articles:

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Software Fischer, L.DZNE*
Software: MTL_PMC_longitudinal_rsFC
Zenodo (2025) [10.5281/zenodo.16103633]2025   Files BibTeX | EndNote: XML, Text | RIS

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