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Changing cognitive chimera states in human brain networks with age: Variations in cognitive integration and segregation

Fig 2

Synchronization framework.

a) The excitatory time series for a single structural connectome after perturbing the left hemisphere insula subregion 1 brain region (belonging to the fronto-parietal cognitive system) with strength P = 1.15 for the entire duration. Top half shows the time series for the individually stimulated brain region and the bottom half shows the responding brain regions’ time series. b) Single snapshot in time of the phases (Eq (8)) represented on the unit circle for a cognitive system (CS) pair, , which are used to determine the amplitude of the complex Kuramoto order parameter (Eq (9)). Specifically, the brain regions that belong to the cingulo-opercular (CO) and motor-sensory (MS) cognitive system are shown, with CO in light pink and MS in dark pink. The length of the black vector arrow represents the amplitude of the complex Kuramoto order parameter, , measuring the synchronization with respective to the CO and MS cognitive systems. This example gives a value of for this snapshot in time. c) Time series of the amplitude of the complex Kuramoto order parameter, . The horizontal line in red, , represents the mean over the time window, s, corresponding to the synchrony (Eq (11)) between the CO and MS cognitive systems. d) Matrix of the synchrony values for all pairwise combinations of the nine cognitive systems. The specific example for the synchrony between CO and MS is outlined with a black square. The remaining cognitive systems are labeled attention (Att), auditory (Aud), fronto-parietal (FP), default mode (DM), subcortical (SC), ventral-temporal (VT), and visual (V) for the synchrony matrix.

doi: https://doi.org/10.1371/journal.pcbi.1013093.g002