Statistics analyses
The SWI and PSD data were normally distributed according to normality Q-Q plots. An analysis of variance (ANOVA) was performed to assess group differences in SWI and PSD, followed by post-hoc analyses with false discovery rate (FDR) correction when overall significant effects were observed. An independent t-test was used for AC and NC group comparisons of SWI. Spearman’s correlation test was used for the correlation analysis between the SWI and cognition scales. Continuous non-normal data were examined using the Kruskal-Wallis or Mann-Whitney U-test for group comparisons. The chi-squared test was used for group comparisons of categorical data. The level of significance was set at p< 0.05. Analyses of SWI and PSD were performed for each frequency band. p -values were FDR-corrected for multiple comparisons. Group comparisons of functional connectivity were corrected using network-based statistic (NBS) (Zalesky et al., 2010). Statistical analyses were performed using IBM SPSS Statistics v22.