Fig. 5: Excitability and phase-locked bursting.

a Measured (dot-dashed lines) and calculated (full line) spiking current as a function of time at various input excitation signals \({V}_{{{{{{\rm{exc}}}}}}}\) = 0–40 mV, and \({V}_{{{{{{\rm{E}}}}}}}(t)\) is a sinusoidal signal with amplitude 20 mV_pp and frequency 5 Hz. b Current-voltage characteristics \({I}_{{{{{{\rm{OEND}}}}}}}\left({V}_{{{{{{\rm{OEND}}}}}}}\right)\) of the OEND (blue full line) and load-line (dashed line) highlighting the impact of the excitation signal. The excitation signal is depicted by a sinusoidal full line superimposed on the load line. c Zoom showing the range where the crossing point is modulated by the excitation signal (thick dark purple line). \({V}_{{{{{{\rm{exc}}}}}}}\) = 0 V, the crossing point is in the silent region and OAN is not spiking. d \({V}_{{{{{{\rm{exc}}}}}}}\) = 10 mV, the crossing point is modulated by the excitation signal as a function of time. The range where the crossing point is in the spiking region and silent region is marked with a thick brighter and a darker purple line, respectively. e \({V}_{{{{{{\rm{exc}}}}}}}\) = 40 mV, the crossing point is in the spiking. The thick bright purple line shows the range where the crossing point is in the spiking. f Spiking current as a function of time at various input excitation signals \({V}_{{{{{{\rm{exc}}}}}}}\) = 0–40 μV.