Fig. 2.

Panel a: Bifurcation diagram of a single isolated ML neuron without autapses against the excitability parameter $v_l$ at a fixed timescale separation parameter $\epsilon =0.0005$. The Hopf bifurcation value separating the excitable regime (blue line) and oscillatory regime (orange line) is indicated by the dashed-gray vertical line located at $v_l=v_{\mathbb{H}}(\epsilon =0.0005)=1.52010$. Panel b: Variation of the Hopf bifurcation value with the timescale parameter $\epsilon$. To avoid oscillatory regime due to Hopf bifurcation, we fixed $v_l=1.515$ in all simulations. Panels c and d show, each, a time series (left) and the associated phase portrait (right) of a trajectory in the excitable regime $v_l=1.515<v_{\mathbb{H}}$ and in the oscillatory regime $v_l=1.525>v_{\mathbb{H}}$, respectively. (Color figure online)