A simple regulatory circuit that can simultaneously generate excitability of two different mechanisms

Coupled positive and negative feedback loops occur in many cellular signaling systems. We show that a two-component circuit with this kind of network structure can simultaneously generate excitability of two different mechanisms that is similar to either integrator or resonator in neuroscience. Moreover, we find that there is an opposite tendency between switching frequencies in the two excitable mechanisms, and the duration and amplitude of the response spike are more resistant to noise in the integrate system than in the resonate system. In addition, we discuss, combining the Bacillis subtilis model organism, some possible biological implications of these differences.