Figure 1.

Model of regular spiking neuron, with $I_{\mathrm{Na}}$ and $I_{\mathrm{K}}$ for spike generation, and slow K+ current ($I_{\mathrm{M}}$) for spike frequency adaptation. (A) (Top) Voltage traces with different amplitudes of the depolarizing pulses (bottom), $V=-85$ mV before the depolarizing pulses. (B) Time to first spike ($t_1$) as a function of the injected current (amplitude of the pulse I). (C) Frequency–current curves ($F/I$), where the instantaneous firing rate (inverse of the inter-spike interval) is represented as a function of I. The curves indicated by different colors correspond to the 1st, the 2nd, the 3rd, and the 10th spikes in the train. (D) Spike frequency F (in color) as function of $g_{\mathrm{M}}$ and I, considering 5.0 s time window. The white line represents the transition where $F>0$ for $g_{\mathrm{T}}$ = 0 and $g_{\mathrm{L}}$ = 0. Additionally, this transition lines for $g_{\mathrm{T}}$ = 0 and $g_{\mathrm{L}}$ = 0.1 mS/cm² (brown line), and $g_{\mathrm{T}}$ = 0.4 mS/cm² and $g_{\mathrm{L}}$ = 0 (yellow line) are shown. Other parameters are $L=d=96.0$$\mu$m, $g_{\mathrm{leak}}=0.01$ mS/cm², $E_{\mathrm{leak}}$ = −85.0 mV, $g_{\mathrm{Na}}$ = 50 mS/cm², $V_{\mathrm{T}}=-55.0$ mV, $g_{\mathrm{K}}=5$ mS/cm², ${\tau }_{\max }$ = 1000 ms, and $g_{\mathrm{M}}$ = 0.03 mS/cm². The absolute values of the membrane potential of (A) are available at https://github.com/FernandoSBorges/BistabilityHH (accessed on 1 September 2023).