Aberrant dynamic functional network connectivity in type 2 diabetes mellitus individuals

Fig.1. Spatial maps of the 31 intrinsic connectivity networks (ICNs). The 31 ICNs were grouped into 12 functional networks based on their anatomical and functional properties. AUN, auditory network; SMN, sensorimotor network; VN, visual network; LECN, left executive control network; RECN, right executive control network; dDMN, dorsal default mode network; vDMN, ventral default mode network; PCUN, precuneus network; SN, salience network; DAN, dorsal attention network; VAN, ventral attention network; CB, cerebellar network. dDMN, vDMN and PCUN belong to default mode network. The spatial maps of each domain are overlaid onto a standard template and represented by color. (Color figure online)

Fig. 2. Four identified dFNC states using k-means clustering method derived from ICA components. Each cluster represents a particular dFNC state. The total number and percentage of the recurrence of each state are listed above each cluster. The colors in the matrices reflect positively correlations (green to red range) or negatively correlations (green to blue range). (Color figure online)

Fig. 3. The dFNC matrices states of HC group. HC, healthy control group. The total number of HC participants involved in each state are listed above. The colors in the matrices reflect positively correlations (green to red range) or negatively correlations (green to blue range). (Color figure online)

Fig. 4. The dFNC matrices states of T2DM group. T2DM, Type 2 diabetes mellitus group. The total number of T2DM participants involved in each state are listed above. The colors in the matrices reflect positively correlations (green to red range) or negatively correlations (green to blue range). (Color figure online)

Fig. 5. Significant group differences of dFNC in each state. T2DM, Type 2 diabetes mellitus group; HC, healthy control group. A, B and C illustrates significant group differences of dFNC between type 2 diabetes mellitus and healthy control group (T2DM − HC) in state 2, 3 and 4 respectively (two sample t-test, P < 0.05, FDR corrected). The results are displayed as -sign (t-statistic) × log10 (p-value). No meaningful value survived state 1. The color reflects higher connectivity (green to red range) or lower connectivity (green to blue range) in type 2 diabetes mellitus than healthy control group. (Color figure online)

Fig. 6. The comparisons between type 2 diabetes mellitus and healthy control group in fraction time and mean dwell time in each dFNC state. T2DM, Type 2 diabetes mellitus group; HC, healthy control group. The top violin figure is a comparison of the fraction time for each state of the two groups, the bottom violin figure is a comparison of the mean dwell time for each state of the two groups. Two asterisks (**) indicate significance level P < 0.01 with Mann–Whitney U test. (Color figure online)

Fig. 7. Correlations between MoCA scores and temporal properties of dFNC. With age and education as covariates, we found significant negative correlation between MoCA scores and the fraction time (Spearman correlation, R = 0.229, P = 0.023) as well as between MoCA scores and the mean dwell time (Spearman correlation, R = 0.223, P = 0.027) in state 4. We also found slightly positive correlations between MoCA scores and the fraction time as well as between MoCA scores and the mean dwell time in state 3, but not statistically significant (P > 0.05). No meaningful correlation survived between MoCA scores and temporal properties of dFNC in state 1 and state 2 (R was close to 0). (Color figure online)