Associations between dynamic functional connectivity and age, metabolic risk, and cognitive performance.

Advanced age is associated with reduced within-network functional connectivity, particularly within the default mode network. Most studies to date have examined age differences in functional connectivity via static indices that are computed over the entire blood-oxygen-level dependent time series. Little is known about the effects of age on short-term temporal dynamics of functional connectivity. Here, we examined age differences in dynamic connectivity as well as associations between connectivity, metabolic risk, and cognitive performance in healthy adults (N = 168; age, 18-83 years). A sliding-window k-means clustering approach was used to assess dynamic connectivity from resting-state functional magnetic resonance imaging data. Three out of 8 dynamic connectivity profiles were associated with age. Furthermore, metabolic risk was associated with the relative amount of time allocated to 2 of these profiles. Finally, the relative amount of time allocated to a dynamic connectivity profile marked by heightened connectivity between default mode and medial temporal regions was positively associated with executive functions. Thus, dynamic connectivity analyses can enrich understanding of age-related differences beyond what is revealed by static analyses.