Fig 1.
Schematic view of the main analysis steps.
(A) 264 regions widely distributed across the entire brain and encompassing key (static) large-scale brain networks, including the SN, CON, FPN, DAN, VAN, subcortical, DMN, memory systems, visual, auditory, sensory-motor, and the cerebellum [3,45]. (B) Time-varying changes in the community structure of intrinsic functional connectivity were quantified using a sliding window approach. An optimized community detection algorithm was used to compute a temporal co-occurrence matrix and multiple graph metrics—(i) temporal flexibility, (ii) spatiotemporal diversity, and (iii) within-community normalized centrality—were used to characterize dynamic functional interactions between brain regions.
Fig 2.
Temporal co-occurrence and time-varying intrinsic functional interactions.
Panels A–C depict results from Session 1 data. (A) Temporal co-occurrence matrix for the 264 brain nodes ordered and labeled according to networks defined by previous studies [3,45]. (B) Average temporal flexibility for brain nodes in each predefined network. SN showed the highest temporal flexibility when compared to all other networks (all ps < 0.001), except for subcortical nodes, which displayed similar levels. (C) Average spatiotemporal diversity for brain nodes in each predefined network. SN showed the highest spatiotemporal diversity (all ps < 0.001), except for subcortical nodes, which displayed similar levels. Panels D–F depict corresponding results from Session 2 data. Error bars stand for standard error of the mean (SEM). (‘***’: p < 0.001).
Fig 3.
Brain regions with high temporal flexibility.
Panels A–C depict results from Session 1 data. (A) Joint profile of temporal flexibility and spatiotemporal diversity identifies a cluster of brain nodes with distinctly high temporal flexibility. (B) Detailed profile of brain nodes within the cluster with high temporal flexibility (inset from panel A). (C) Brain nodes with high temporal flexibility are primarily from the SN, subcortical regions, and FPN, with the highest percentage belonging to the SN. Panels D–F depict corresponding results from Session 2 data.
Fig 4.
Spatiotemporal diversity and centrality of brain regions with high temporal flexibility.
Panels A–B depict results from Session 1 data. (A) SN nodes have the highest spatiotemporal diversity compared to all other brain regions (all ps < 0.001), except for subcortical nodes, which showed similar levels. (B) SN nodes also showed the highest normalized centrality (all ps < 0.001), except for CON nodes, which displayed similar levels. Panels C–D depict corresponding results from Session 2 data. Error bars stand for SEM. (‘***’: p < 0.001, ‘*’: p < 0.05).
Fig 5.
SN temporal flexibility predicts cognitive flexibility behavioral measures.
Panel (A) shows results from a CCA using cross-validation on Session 1 data. Scatter plot shows predictions of individual cognitive flexibility based on SN temporal flexibility. Panel (B) shows results from Session 2 data. (‘***’: p < 0.001, ‘*’: p < 0.05).