Figure 3:

The variables that are used to define the Poincaré maps are shown on the simulation of ML neurons. The cycle length P_n of cell A in cycle n (measured when voltage crosses V_th) can be divided into the delay between cell A activity to cell B activity (dt_n) and the opposite (dτ_n). The cycle period Q_n of cell B in cycle n is dτ_n+dτ_n+1.