Structural anomalies in brain networks induce dynamical pacemaker effects

TL;DR

This study uses numerical simulations of multilayer brain networks derived from MRI data to reveal how structural anomalies like tumors induce pacemaker effects and alter dynamical states, aiding early tumor detection.

Contribution

It demonstrates that structural anomalies cause distinct dynamical effects, such as pacemaker waves, in brain network models using two neuronal models, advancing understanding of tumor-induced brain dynamics.

Findings

Healthy brains show chimera-like states with coherent regions in high white matter areas.

Tumorous brains produce traveling waves originating at tumor sites, acting as pacemakers.

Consistent results across two neuronal models validate the findings.

Abstract

Dynamical effects on healthy brains and brains affected by tumor are investigated via numerical simulations. The brains are modeled as multilayer networks consisting of neuronal oscillators, whose connectivities are extracted from Magnetic Resonance Imaging (MRI) data. The numerical results demonstrate that the healthy brain presents chimera-like states where regions with high white matter concentrations in the direction connecting the two hemispheres act as the coherent domain, while the rest of the brain presents incoherent oscillations. To the contrary, in brains with destructed structure traveling waves are produced initiated at the region where the tumor is located. These areas act as the pacemaker of the waves sweeping across the brain. The numerical simulations are performed using two neuronal models: a) the FitzHugh-Nagumo model and b) the Leaky Integrate-and-Fire model. Both models give consistent results regarding the chimera-like oscillations in healthy brains and the pacemaker effect in the tumorous brains. These results are considered as a starting point for further investigation in the detection of tumors with small sizes before becoming discernible on the MRI recordings, as well as in tumor development and evolution.