Abstract
Functional connectivity (FC), obtained from functional magnetic resonance imaging (fMRI), brings insights into the functional organization of the brain. Recently, rich and complex behaviour of brain has been revealed by the dynamic fluctuation of FC, which had previously been regarded as confounding ‘noise’. While the dynamics of long-distance, inter-regional FC has been extensively studied, the dynamics of local FC within a few millimetres in space remains largely unexplored. In this study, the local FC was depicted by regional homogeneity (ReHo), and the dynamics of local FC was obtained using sliding windows method. We observed a robust positive correlation between ReHo and its temporal variability, which was shown to be an intrinsic feature of the brain rather than a pure stochastic effect. Furthermore, fluctuation of ReHo was associated with global functional organization: (i) brain regions with higher centrality of inter-regional FC tended to possess higher ReHo variability; (ii) coherence of ReHo fluctuation was higher within brain’s functional modules. Finally, we observed alteration of ReHo variability during a motor task compared with resting-state. Our findings associated the temporal fluctuation of ReHo with brain function, opening up the possibility of dynamic local FC study in the future.
Highlights
Functional connectivity (FC), obtained from functional magnetic resonance imaging, brings insights into the functional organization of the brain
Most studies of resting-state functional magnetic resonance imaging (rs-functional magnetic resonance imaging (fMRI)) were conducted under the assumption that the functional connectivity (FC) in human brain remains stationary in resting state, and longer scanning time was recommended to improve the reliability of the results
regional homogeneity (ReHo) and ReHo variability (ReHoV) showed apparent correlation across voxels, as demonstrated in their joint probabilistic distribution function (PDF) (Fig. 1c). These results suggested that the linear correlation between ReHo and ReHoV is not a coincidence caused by region of interest (ROI) definition
Summary
Functional connectivity (FC), obtained from functional magnetic resonance imaging (fMRI), brings insights into the functional organization of the brain. Our findings associated the temporal fluctuation of ReHo with brain function, opening up the possibility of dynamic local FC study in the future. As human brain organizes as a complicated network in terms of structure and function, rs-fMRI studies primarily focus on functional connectivity (FC) between brain regions[1]. Most studies of rs-fMRI were conducted under the assumption that the FC in human brain remains stationary in resting state, and longer scanning time was recommended to improve the reliability of the results. Other studies have reported relationships between ReHo and many factors including age[24], gender[24,25], and intelligence[26] These findings indicated that the localized brain connectivity is associated with the physiological, pathological, and psychological changes in human brain[27]. This study enriches our understanding of regional brain connectivity, and underscore the need for further exploration of the brain’s dynamic FC at a local scale
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
