Inter-regional BOLD signal variability is an organizational feature of functional brain networks

• Main Authors: Giulia Baracchini, Bratislav Mišić, Roni Setton, Laetitia Mwilambwe-Tshilobo, Manesh Girn, Jason S. Nomi, Lucina Q. Uddin, Gary R. Turner, R. Nathan Spreng
• Format: Article
• Language: English
• Published: Elsevier 2021-08-01
• Series: NeuroImage
• Online Access: http://www.sciencedirect.com/science/article/pii/S1053811921004262

Neuronal variability patterns promote the formation and organization of neural circuits. Macroscale similarities in regional variability patterns may therefore be linked to the strength and topography of inter-regional functional connections. To assess this relationship, we used multi-echo resting-state fMRI and investigated macroscale connectivity-variability associations in 154 adult humans (86 women; mean age = 22yrs). We computed inter-regional measures of moment-to-moment BOLD signal variability and related them to inter-regional functional connectivity. Region pairs that showed stronger functional connectivity also showed similar BOLD signal variability patterns, independent of inter-regional distance and structural similarity. Connectivity-variability associations were predominant within all networks and followed a hierarchical spatial organization that separated sensory, motor and attention systems from limbic, default and frontoparietal control association networks. Results were replicated in a second held-out fMRI run. These findings suggest that macroscale BOLD signal variability is an organizational feature of large-scale functional networks, and shared inter-regional BOLD signal variability may underlie macroscale brain network dynamics.