title: Time-resolved detection of stimulus/task-related networks, via clustering of transient intersubject synchronization.
abstract: Several methods are available for the identification of functional networks of brain areas using functional magnetic resonance imaging (fMRI) time-series. These typically assume a fixed relationship between the signal of the areas belonging to the same network during the entire time-series (e.g., positive correlation between the areas belonging to the same network), or require a priori information about when this relationship may change (task-dependent changes of connectivity). We present a fully data-driven method that identifies transient network configurations that are triggered by the external input and that, therefore, include only regions involved in stimulus/task processing. Intersubject synchronization with short sliding time-windows was used to identify if/when any area showed stimulus/task-related responses. Next, a first clustering step grouped together areas that became engaged concurrently and repetitively during the time-series (stimulus/task-related networks). Finally, for each network, a second clustering step grouped together all the time-windows with the same BOLD signal. The final output consists of a set of network configurations that show stimulus/task-related activity at specific time-points during the fMRI time-series. We label these configurations: "brain modes" (bModes). The method was validated using simulated datasets and a real fMRI experiment with multiple tasks and conditions. Future applications include the investigation of brain functions using complex and naturalistic stimuli.
authors.affiliation: Neuroimaging Laboratory, IRCCS, Santa Lucia Foundation, via Ardeatina 306, Rome, 00179, Italy.
authors.forename: Cécile
authors.initials: C
authors.lastname: Bordier
authors.affiliation: Neuroimaging Laboratory, IRCCS, Santa Lucia Foundation, via Ardeatina 306, Rome, 00179, Italy.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Macaluso
mesh_terms: D000328:Adult; D001307:Auditory Perception / Q000502:physiology; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D002560:Cerebrovascular Circulation / Q000502:physiology; D016000:Cluster Analysis; D003198:Computer Simulation; D066264:Datasets as Topic; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008959:Models, Neurological; D009043:Motor Activity / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D014796:Visual Perception / Q000502:physiology; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: cluster analysis; data-driven; functional magnetic resonance imaging; intersubject synchronization; network configurations