RT Journal Article
SR Electronic
T1 Stereotypical modulations in dynamic functional connectivity explained by changes in BOLD variance
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 126524
DO 10.1101/126524
A1 Katharina Glomb
A1 Adrián Ponce-Alvarez
A1 Matthieu Gilson
A1 Petra Ritter
A1 Gustavo Deco
YR 2017
UL http://biorxiv.org/content/early/2017/04/12/126524.abstract
AB Spontaneous activity measured in human subject under the absence of any task exhibits complex patterns of correlation that largely correspond to large-scale functional topographies obtained with a wide variety of cognitive and perceptual tasks. These “resting state networks” (RSNs) fluctuate over time, forming and dissolving on the scale of seconds to minutes. While these fluctuations, most prominently those of the default mode network, have been linked to cognitive function, it remains unclear whether they result from random noise or whether they index a non-stationary process which could be described as state switching.In this study, we use a sliding windows approach to relate temporal dynamics of RSNs to global modulations in correlation and BOLD variance. We compare empirical data, phase-randomized surrogate data, and data simulated with a stationary model. We find that RSN time courses exhibit a large amount of coactivation in all three cases, and that the modulations in their activity are closely linked to global dynamics of the underlying BOLD signal.We find that many properties of the observed fluctuations in FC and BOLD, including their ranges and their correlations amongst each other, are explained by fluctuations around the average FC structure. However, we also encounter interesting characteristics that are not explained in this way. In particular, we find that the brain spends more time in the peaks and troughs of modulations than can be expected from stationary dynamics.