Fig 1.
Resting-state fMRI preprocessing.
Fig 2.
The uncorrected (top panel) and corrected (bottom) p-values (upper triangular matrix) of testing the paired difference of the Pearson Functional Correlations between the young and the elderly groups, (elderly–young).
The ROI pairs with significant difference are marked in blue for negative values and in red for positive values in the lower triangular matrix.
Fig 3.
Cortical-Cortical Connectivity (CCC) matrices for the young (top) and the elderly (bottom) groups.
The colors on the upper triangular matrices indicate the PFCorr connectivity intensity of the ROI pairs. The gray spots on the lower triangular matrices indicate ROI pairs with statistically significant nonzero correlations.
Fig 4.
Paired differences of the brain connectivity matrices between the young and the elderly groups ().
The colors on the upper triangular matrix indicate the PFCorr difference of the ROI pairs. The significantly different ROI pairs are shown on the lower triangular matrix, with negative values marked in blue and positive values marked in red.
Fig 5.
The distinguished normal ageing effects across the cortical lobes.
E: elderly group; Y: young group; E-Y: ageing effects (elderly group subtracts young group). Connectivity 1 denotes the connectivity from the frontal lobe to posterior lobes; Connectivity 4, 5, 6 are the interlobe connectivities among the posterior lobes: Connectivity 4 connects the temporal and occipital lobes, Connectivity 5 connects the parietal and occipital lobes, and Connectivity 6 connects the temporal and parietal lobes.
Fig 6.
Histograms of the normal aging effects on inter-lobe functional connectivities.
The distribution curves indicate that inter-lobe connectivities of the frontal lobe tend to increase with age, whereas those among posterior lobes tend to decrease with age.
Table 1.
Performance comparison of the estimated functional correlations based on bias, standard error and mean square error for Scenario 1 and Scenario 2.
Fig 7.
Cortical-Cortical Connectivity (CCC) matrices for the young (top) and the elderly (bottom) groups.
The colors on the upper triangular matrices indicate the average individual-centered functional connectivity intensity of the ROI pairs. The gray square elements on the lower triangular matrices indicate ROI pairs with statistically significant nonzero correlations.