Dynamic Functional Connectivity as a complex random walk: Definitions and the dFCwalk toolbox
Lucas Arbabyazd, Diego Lombardo, Olivier Blin, Mira Didic, Demian Battaglia, Viktor Jirsa
Abstract
Functional Connectivity, describing the interaction between brain regions beyond their anatomical interconnection, is highly dynamic even when no task is performed ("resting state") and it remains a methodological challenge to properly describe its changes in time without strong assumptions. We have developed a framework to describe the dynamics of Functional Connectivity (dFC) estimated from brain activity time-series as a as a smooth reconfiguration process, combining "liquid" and "coordinated" aspects. Our framework considers dFC as a complex random walk in the space of possible functional networks. Unlike other previous approaches, our method does not require the explicit extraction of discrete connectivity states but tracks changes in a continuous time fashion.