Frequency Enhancement in Coupled Noisy Excitable Elements

The oscillatory dynamics of coupled noisy excitable FitzHugh-Nagumo elements is investigated as a function of the coupling strength~$g$. For two such coupled elements, it~is found that their frequencies are enhanced by the coupling and will synchronize at a frequency~higher than the uncoupled frequencies of each element. As~$g$ increases, there is an unexpected peak~in the mean of frequency distribution~before reaching synchronization at the optimal coupling strength.~This phenomenon~can be understood with a simplified analytic model~based on the excitation~across a potential barrier whose height is controlled by $g$~as well as the formation of temporary coherent cluster.