Caballero, C.
Basque Center on Cognition, Brain and Language
A plethora of sensory and association brain areas must dynamically and coherently communicate to each other in order to integrate, process and respond to internal and external stimuli. Such functional brain networks exhibit a degree of synchronous activity that is not only fundamental to support cognition and behaviour, but also remarkably informative in the resting state (RS). Traditionally, BOLD fMRI RS functional connectivity studies have implicitly assumed a static interdependence between the signals of different brain regions. Only few works have investigated the wealth of information available in the non-stationarity of spontaneous BOLD activity, and evidenced these dynamics can reveal important aspects of brain function. For instance, functional brain networks can be distinctly mapped by considering as few as 15% critical time points of the signal (a.k.a. point process analysis (PPA)), which are then spatially clustered. However, this approach is likely to be prone to signal artefacts and non-physiological fluctuations that modulate the BOLD signal. Here, we demonstrate that paradigm free mapping, a novel analysis tool that detects single-trial BOLD events without prior timing information, can serve as a more robust method to investigate the dynamics of functional brain connectivity, avoiding ad-hoc choices of the number of critical time points and amplitude thresholds inherent to PPA. Our results further corroborate that RS functional connectivity is driven by brief spontaneous BOLD events.