Dynamic regulation of resource transport induces criticality in multilayer networks of excitable units.

Past work has shown that the function of a network of excitable units can be enhanced if the network is in the `critical regime', where excitations are, one average, neither damped nor amplified. In this Letter, we show that resource transport dynamics can robustly maintain the network dynamics in the critical regime. More specifically, we consider the example of a neural network with neurons (nodes) and synapses (edges). We propose a model where synapse strengths are regulated by metabolic resources distributed by a secondary network of glial cells. We find that this two-layer network robustly preserves the critical state and produces power-law distributed avalanches over a wide range of parameters. In addition, the glial cell network protects the system against the destabilizing effect of local variations in parameters and heterogeneity in network structure. For homogeneous networks, we derive a reduced 3-dimensional map which reproduces the behavior of the full system.