Simulation results (solid lines) of the models a, b, and c as compared with the mathematical equation (broken lines) describing the cellular response to double-pulse stimuli. In all panels shown, the reaction time tR is plotted against various parameters. (A,D,G) A single light pulse with 20 or 100 msec duration and variable intensity is applied to the cells. The value of the reciprocal intensity is given on the abscissa. (B,E,H) Double pulses are applied with a duration of the first pulse of τ1 = 25 msec and of the second pulse of τ2 = 75 msec, whereas the dark time between the two pulses is varied. (C,F,I) Results of double-pulse experiments with a constant total duration of τ = 100 msec, a dark period of D = 800 msec and variable ratio of the two pulses.
