All Phase Resetting Curves Are Bimodal, but Some Are More Bimodal Than Others
Figure 3
All PRCs, including Type I, are bimodal. The bimodality increases while the system moves away from the SNIC bifurcation point that generated the stable limit cycle oscillations. Very close to the SNIC bifurcation point (A1) , the positive portion (delay of the next spike induced by a depolarization) is not even visible, unless we magnify it 1000 times (solid dots in panel (B1)). The bimodality of the PRC becomes more transparent away from the SNIC bifurcation; for example, (B1), (C1), and (D1), respectively. The amplitude of the positive lobe of the PRC is magnified 1000 times (large solid circles) and plotted together with the action potential (dashed line). The two neutral points where no resetting occurs are both on the repolarizing slope of the action potential (see the vertical dashed lines in all panels of the second column).
