The activity of the cortex in mammals constantly fluctuates in relation to cognitive tasks, but also during rest. The ability of brain regions to display ignition, a fast transition from low to high activity is central for the emergence of conscious perception and decision making. In our recently published paper in PLoS Computational Biology (in collaboration with Patricio Orio, in Valparaiso) we show how the structural organization of human cortex supports and constrains the rise of this ignited dynamics in spontaneous cortical activity.
Using a biophysically inspired computational mean-field model of cortical activity, we found that the weighted core-shell organization of the human connectome allows for a uniquely graded ignition. This graded ignition implies a smooth control of the ignition in cortical areas tuned by the global excitability. The smooth control cannot be replicated by surrogate connectomes, even though they conserve key local or global network properties. Indeed, ignition in the human cortex is first triggered on the strongest and most densely interconnected cortical areas–the “ignition core”–, emerging at the lowest global excitability value compared to surrogate connectomes.
In conclusion, it looks like the human connectome displays uniquely non-random features of a novel type: the capability of supporting exotic dynamical states, extremely unlikely to arise with less specific inter-regional wiring. Special connectomes may thus allow special dynamics that support the emergence of special functions…
To know more about this:
- S. Castro, W. El-Deredy, D. Battaglia*, P. Orio* (2020). Cortical ignition dynamics is tightly linked to the core organisation of the human connectome. PLoS Comput Bio 16, e1007686 [* Shared last authorship].