Transmission time delays organize the brain network synchronization
Résumé
Timings of the activity at brain regions is of crucial importance for its functioning, and they can be described by their phases if the underlying processes are oscillatory. The structure of the brain constrains its oscillatory dynamics through the delays due to propagation and the strengths of the white matter tracts. We use self-sustained delay-coupled nonlinear, non-isochronous and chaotic oscillators to study how spatio-temporal structure of the brain governs phase lags between oscillatory activity at distant regions. In a previous study of Kuramoto oscillators we identified the heterogeneity of time-delays as the main mechanism in shaping the global in and anti-phase inter-hemispheric synchronization and the lagging in phase of the stronger connected regions. Here, we numerically confirm these features for amplitude oscillators and we show that increased frequency and coupling, generally distort oscillators by decreasing their amplitude, and stronger connected nodes have lower amplitudes. Also, the anti-phase regime is more robust, especially for chaotic oscillators, and it is no longer only sporadic. Taken together the results indicate specific features in the phase relationships of the brain regions that need to hold for any underlying oscillatory dynamics, given that the time-delays of the connectome are proportional to the lengths of the links.
Origine : Publication financée par une institution
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