caption: Bifurcation diagrams and the oscillation region of the AI mean value for the evolution equations. (A) and (B) figures show the bifurcation diagrams by the noise deviation σ (A), and by the time delay (B). The two curves show the stable steady state of the AI concentration, as well as the maximum and minimum concentrations of AI in the course of oscillation. (C) shows the oscillatory and steady state regions by the noise deviation σ and the coupling strength d. The oscillatory region grows with the noise deviation.