Fig. 1.

Single bursting HR neuron for $D=0$. a Bifurcation diagram in the single HR neuron. Solid line represents a stable resting state, while for the bursting state, maximum and minimum values of the membrane potential x are denoted by solid circles. b Bursting frequency $f_b$ versus $I_{\mathit{DC}}$. c Time series of x(t) for the bursting state when $I_{\mathit{DC}}=1.35$. The dotted horizontal line ($x_b^{\ast }=-1$) and the dashed horizontal line ($x_s^{\ast }=0$) denote the bursting and the spiking thresholds, respectively. The solid and open circles represent the burst onset and offset times, respectively