Typical bursting patterns and AP parameters of bursting pacemakerneuron. (A) Bursting patterns of bursting pacemaker neuron; membrane potentialvs. time. The electrophysiological parameters related to burst firing containthe intraburst interspike interval, the duration between the two points ofsequential Vpp within one burst firing event [A (1)];interburst interval, the duration between the two points of the lastVpp of one burst firing event and the first Vpp ofnext burst firing event [A (2)]; and burst duration, the durationbetween the two points of the first Vpp and the last Vppwithin one burst firing event [A (3)]. (B) Definition of APparameters. The maximum point T on the upper part of AP means a positive peakmembrane potential, Vpp and the minimum point B on the lower part ofAP means a negative peak membrane potential, Vnp. H1 and H2 meansthe half point of potential difference during the rising phase and the fallingphase of AP, respectively. The last half of the rising phase,Δtr2 designate the time intervals between the two point H1and T. The first half of the falling phase of AP, Δtf1 isdefined as the time interval between point T and point H2. The angleθ1 shows the inverse tangent of the ratio of halfAAP to Δtr2 and angle θ2 means the inversetangent of the ratio of half AAP to Δtf1.