Figure 1.

Illustrations of (A–C) phase planes and (D–F) bifurcation diagrams in the fast subsystem. The characteristics of neuronal activities can be adjusted by exploiting their mechanisms explained in the main text. For example in (A), the threshold voltage can be increased while the resting membrane potential is held constant if (T) is displaced rightward while (S) is fixed by tuning the slope of the v- or n-nullcline. The ratio of the time constants of n and v is one of the factors that determine the shape of the stable and unstable manifolds of (T) and the limit cycle.