  We introduce a framework to intertwine dynamical processes of different
nature, each with its own distinct network topology, using a multilayer network
approach. As an example of collective phenomena emerging from the interactions
of multiple dynamical processes, we study a model where neural dynamics and
nutrient transport are bidirectionally coupled in such a way that the
allocation of the transport process at one layer depends on the degree of
synchronization at the other layer, and vice versa. We show numerically, and we
prove analytically, that the multilayer coupling induces a spontaneous
explosive synchronization and a heterogeneous distribution of allocations,
otherwise not present in the two systems considered separately. Our framework
can find application to other cases where two or more dynamical processes such
as synchronization, opinion formation, information diffusion, or disease
spreading, are interacting with each other.
