Distinct contribution of brain geometry and connectivity for whole-cortex communication
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Background: The brain mechanisms that describe how neural signals propagate throughout the cortex are poorly defined. This knowledge is essential to understand altered patterns of neural communications in mental disorders and develop effective and targeted therapeutic interventions. Recent findings suggest that the decomposition of neural signals with cortical geometry alone (cortical eigenmodes) can be used to understand the emergence of macroscopic cortical dynamics. \n Methods: \n We used novel methods to estimate cortical eigenmodes, describing the distinct contribution of cortical geometry and brain wiring (the connectome) in supporting cortical dynamics. We assessed how eigenmodes support and predict whole-cortex signal propagation using an empirical dataset of single-pulse transcranial magnetic stimulation (TMS) given to three cortical regions. \n Results: \n Results show that eigenmodes can accurately capture how a local perturbation in neural activity evolves into a widespread cortical response. Furthermore, eigenmodes provide key insights into how perturbation size, location, timing and intensity affect the spread of changes in local neural signals. We also showed that long-range brain connections are required to fully account for the observed changes in whole-cortex activity. \n Conclusions: \n Our results advance knowledge of large-scale brain communication by highlighting the distinct contribution of brain geometry and anatomical connectivity to carry neural signals across the cortex. These findings are important to understand macroscopic changes in cortical activity observed across mental disorders and develop targeted neuromodulatory interventions to restore cortical communication.
