Fault tolerance in noise-enhanced propagation

As a mock-up of synaptic transmission between neurons, we revisit a problem that has recently risen the interest of several authors: the propagation of a low-frequency periodic signal through a chain of one-way coupled bistable oscillators, subject to uncorrelated additive noise. On a numerical study performed in the optimal range of noise intensity for which essentially undamped transmission along the chain has been reported, we focus on the outcome of feeding with noise all the nodes but the central one. A (moderate) critical value of the coupling between oscillators is found such that whereas below it the propagation can be considered to be interrupted at the “dead neuron,” it is reestablished above it. Thus, one of the distinguishing features of synaptic transmission, namely, a fault-tolerant behavior that enhances reliability at the expense of efficiency, arises here as an emergent property of the system.