Fig 2. Phase diagram for parameters c and d while fixing a = 0.02 and b = 0.2, which is the common parameter values for RS, IB, and CH seen in Ref. [18].

This plot is obtained at integrating step-size of h = 5 × 10⁻³, and resolution of parameters c and d is 2 × 10⁻². Each shade of colour is assigned after systematical examination of the time series of the membrane potential, v, in accordance to that displayed in Fig 1.