Figure 1: Functional connectivity at long time scales constrains the range over which functional connectivity is expected to vary at shorter time scales (A) Four pairs of real BOLD time series whose static connectivity varies from ρ = 0 . 11 (blue), ρ = 0 . 33 (yellow), ρ = 0 . 55 (green), and ρ = 0 . 77 (red). (B) We then sub-divided the full time series into 730 windows containing 156 time points each (the same parameters used for generating dynamic FC matrices), estimated dynamic FC for each window, and then plotted the histogram of dynamic FC magnitude. (C) In general, the distribution is centered around the magnitude of the static connection and also becomes tighter and more skewed as the static connection increases in magnitude. The top panel shows the magnitude of static connectivity on the x-axis and the median (50th percentile) of dynamic connectivity on the y-axis. The two curves are correlated to a value of 0.95. The bottom panel shows the magnitude of static connectivity plotted against the range of the 95% confidence interval for the distribution of dynamic fluctuations (i.e. we expect that 95% of all dynamic functional connection magnitudes will fall within this range). 39