Response of coupled noisy excitable systems to weak stimulation

It is known that coupling can enhance the response of noisy bistable device s to weak periodic modulation. This work examines whether a similar phenome non occurs in the active rotator model for excitable systems. We study the dynamics of assemblies of weakly periodically modulated active rotators. Th e addition of noise to these brings about a number of behaviors that have n o counterpart in networks of bistable systems. The analysis of the dynamics of the solution of the Fokker-Planck equation of active rotator networks s hows that these new behaviors are similar to generic responses of periodica lly forced autonomous oscillators. This is because noise alone, in the abse nce of other inputs, can regularize the dynamics of single active rotators through coherence resonance, and lead to regular synchronous activity at th e level of networks. We argue that similar phenomena take place in a broad class of excitable systems. [S1063-651X(99)14408-8].