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bioRxiv · 10.1101/2020.06.29.164343

Whole-brain dynamics in aging: disruptions in functional connectivity and the role of the rich club

Escrichs, A.·Biarnes, C.·Garre-Olmo, J.·Fernandez-Real, J. M.·Ramos, R.·Pamplona, R.·Brugada, R.·Serena, J.·Ramio-Torrenta, L.·Coll-De-Tuero, G.·Gallart, L.·Barretina, J.·Vilanova, J. C.·Mayneris-Perxachs, J.·Essig, M.·Figley, C. R.·Pedraza, S.·Puig, J.·Deco, G.
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Abstract

Normal aging causes disruptions in the brain that can lead to cognitive decline. Resting-state fMRI studies have found significant age-related alterations in functional connectivity across various networks. Nevertheless, most of the studies have focused mainly on static functional connectivity. Studying the dynamics of resting-state brain activity across the whole-brain functional network can provide a better characterization of age-related changes. Here we employed two data-driven whole-brain approaches based on the phase synchronization of blood-oxygen-level-dependent (BOLD) signals to analyze resting-state fMRI data from 620 subjects divided into two groups ( middle-age group (n=310); age range, 50-65 years vs. older group (n=310); age range, 66-91 years). Applying the Intrinsic-Ignition Framework to assess the effect of spontaneous local activation events on local-global integration, we found that the older group showed higher intrinsic ignition across the whole-brain functional network, but lower metastability. Using Leading Eigenvector Dynamics Analysis, we found that the older group showed reduced ability to access a metastable substate that closely overlaps with the so-called rich club. These findings suggest that functional whole-brain dynamics are altered in aging, probably due to a deficiency in a metastable substate that is key for efficient global communication in the brain.

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Escrichs, A., Biarnes, C., Garre-Olmo, J., Fernandez-Real, J. M., Ramos, R., Pamplona, R., Brugada, R., Serena, J., Ramio-Torrenta, L., Coll-De-Tuero, G., Gallart, L., Barretina, J., Vilanova, J. C., Mayneris-Perxachs, J., Essig, M., Figley, C. R., Pedraza, S., Puig, J., Deco, G.. 2020-06-29. Whole-brain dynamics in aging: disruptions in functional connectivity and the role of the rich club. https://doi.org/10.1101/2020.06.29.164343

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