Effect of nonidentical signal phases on signal amplification of two coupled excitable neurons

In this paper, we study the response of two coupled excitable neurons to external subthreshold periodic signals. We find that the neurons' response to the subthreshold signals can be enhanced when the signal phases are nonidentical. Moreover, we find that the response can be strongly improved if the level of nonidentical signal phases is at an intermediate value and thus resulting in a resonance-like phenomenon. Furthermore, under the influence of nonidentical signal phases, the response also exhibits a resonance-like dependency on the coupling coefficient. Moreover, we give an analysis to understand the mechanism of these two types of resonance behaviors. Finally, we discuss the robustness of the resonances induced by nonidentical signal phases to neuronal diversity, noise perturbation and different neuron model. We believe that the phenomena found in this paper will be useful for understanding neural information processing.