Article Figures & Data
Figures
- Figure 1.
Illustration of task and analysis steps. A, Subjects were scanned in two different conditions, with eyes open at rest while fixating and during a size-congruency task administered in the form of a conflict adaptation paradigm. In the latter, on individual trials, participants were presented with two digits that differed in physical and numerical size, and pressed a button corresponding to the location of the numerically larger digit. On compatible trials, the numerically larger digit was also physically larger. On incompatible trials, the numerically larger digit was physically smaller. Individual trials were administered in conditions that differed in the proportion of overall trials that were compatible (25% or 75%). B, Data across subjects and conditions were decomposed using Group ICA into C = 90 components, 56 of which were identified as ICNs. GICA1 back-reconstruction was used to estimate the time courses (Ri) and spatial maps (Si) for each subject. C, Dynamic FC was estimated as the series of correlation matrices from windowed portions (W) of Ri, resulting in a concatenated data matrix of all ICN-to-ICN paired correlation values over time. D, Estimation of k was performed to select an optimal cluster number for clusters and then, following steps outlined in Allen et al., 2014, k-means was performed on the concatenated data matrix, resulting in a labeling of each window to a cluster and cluster centroids (state) that can be back-projected into the original matrix format. E, Variance in the correlation strength of each IC-to-IC coupling pair (IC2ICVar) was computed separately for the two conditions.
- Figure 2.
Spatial profiles of the 56 neurophysiologically plausible ICNs revealed by a high-model order group ICA displayed on the medial and lateral views of the cortical surface. ICNs are grouped, and boxes are color coded based on their assignment, which is shown in Figure 3. In cases where a view or hemisphere is missing, no voxels above the lower-bound threshold (z > 0.75) were present.
- Figure 3.
Static (mean) functional network connectivity correlation matrix of ICNs across task and rest. Labels are color coded to match Figure 2.
- Figure 4.
Age-related correlations of static (mean) functional network connectivity. The bottom triangle of the matrix displays the correlation of ICNs across task and rest with age. The top matrix shows the statistically significant correlations at FDR thresholds of q = 0.01 (yellow) and q = 0.05 (orange).
- Figure 5.
Age- and condition-dependent state expression. State solutions are shown for 12 states that were expressed by more than one subject. Below each ICN-to-ICN state matrix are distribution plots for frequency (left) and MDT (right) across ages for rest (blue circles) and task (red circles). Bold text marked by asterisks indicates significant main effects or interactions. a, Age; c, condition; mot, motion; r, rest; t, task.
- Figure 6.
Temporal properties of state expression. The distribution of the number of transitions (top) and the time between transitions (bottom) of the 12 states shown in Figure 5 are plotted across ages for rest (blue circles) and task (red circles).
- Figure 7.
Age-related differences in internetwork connectivity variability. A, B, Variance in the ICN-to-ICN coupling strength was estimated for each pairwise ICN-to-ICN coupling, separately for rest (A) and task (B). Each coupling strength variability estimate was then correlated with age. Positive correlations (warm colors) indicate that connectivity variability was greater among older than younger participants; negative correlations (cool colors) indicate that variability was greater among younger than older participants. C, A statistical test of the interaction of age and condition, FDR corrected for multiple comparisons (q = 0.01), reveals coupling pairs whose correlation was more variable at rest than task for older relative to younger participants. No coupling pairs were more variable at rest than task for younger participants. D, Correlation of ICN-to-ICN variability and RT variability, FDR corrected (q = 0.05). E, Correlation of ICN-to-ICN variability and error rate, FDR corrected (q = 0.05). F, Conjunction of D and E.
- Figure 8.
Average state fit of children (<216 months) and adults (≥216 months). A–L, Bars represent the mean spatial correlation of all windowed patterns with the canonical state configuration to which it was assigned by k-means clustering, derived separately for children (blue) and adults (red). Error bars represent 1 SD.
