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Reorganization of brain structural networks in aging: A longitudinal study

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DOI

  • Ana Coelho, University of Minho, ICVS/3B's – PT Government Associate Laboratory, Clinical Academic Center - Braga
  • ,
  • Henrique M. Fernandes
  • Ricardo Magalhães, University of Minho, ICVS/3B's – PT Government Associate Laboratory, Clinical Academic Center - Braga
  • ,
  • Pedro S. Moreira, University of Minho, ICVS/3B's – PT Government Associate Laboratory, Clinical Academic Center - Braga
  • ,
  • Paulo Marques, University of Minho, ICVS/3B's – PT Government Associate Laboratory, Clinical Academic Center - Braga
  • ,
  • José M. Soares, University of Minho, ICVS/3B's – PT Government Associate Laboratory, Clinical Academic Center - Braga
  • ,
  • Liliana Amorim, University of Minho, ICVS/3B's – PT Government Associate Laboratory, Clinical Academic Center - Braga
  • ,
  • Carlos Portugal-Nunes, University of Minho, ICVS/3B's – PT Government Associate Laboratory, Clinical Academic Center - Braga
  • ,
  • Teresa Castanho, University of Minho, ICVS/3B's – PT Government Associate Laboratory, Clinical Academic Center - Braga
  • ,
  • Nadine Correia Santos, University of Minho, ICVS/3B's – PT Government Associate Laboratory, Clinical Academic Center - Braga
  • ,
  • Nuno Sousa, University of Minho, ICVS/3B's – PT Government Associate Laboratory, Clinical Academic Center - Braga

Normal aging is characterized by structural and functional changes in the brain contributing to cognitive decline. Structural connectivity (SC) describes the anatomical backbone linking distinct functional subunits of the brain and disruption of this communication is thought to be one of the potential contributors for the age-related deterioration observed in cognition. Several studies already explored brain network's reorganization during aging, but most focused on average connectivity of the whole-brain or in specific networks, such as the resting-state networks. Here, we aimed to characterize longitudinal changes of white matter (WM) structural brain networks, through the identification of sub-networks with significantly altered connectivity along time. Then, we tested associations between longitudinal changes in network connectivity and cognition. We also assessed longitudinal changes in topological properties of the networks. For this, older adults were evaluated at two timepoints, with a mean interval time of 52.8 months (SD = 7.24). WM structural networks were derived from diffusion magnetic resonance imaging, and cognitive status from neurocognitive testing. Our results show age-related changes in brain SC, characterized by both decreases and increases in connectivity weight. Interestingly, decreases occur in intra-hemispheric connections formed mainly by association fibers, while increases occur mostly in inter-hemispheric connections and involve association, commissural, and projection fibers, supporting the last-in-first-out hypothesis. Regarding topology, two hubs were lost, alongside with a decrease in connector-hub inter-modular connectivity, reflecting reduced integration. Simultaneously, there was an increase in the number of provincial hubs, suggesting increased segregation. Overall, these results confirm that aging triggers a reorganization of the brain structural network.

Original languageEnglish
JournalJournal of Neuroscience Research
Volume99
Issue5
Pages (from-to)1354-1376
Number of pages23
ISSN0360-4012
DOIs
Publication statusPublished - May 2021

Bibliographical note

Publisher Copyright:
© 2021 The Authors. Journal of Neuroscience Research published by Wiley Periodicals LLC

Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.

    Research areas

  • aging, cognitive performance, diffusion MRI, network, white matter

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