图5. 在膜电位的不同相位($\Delta t)$再次施加抑制性脉冲诱发第二个动作电位的脉冲强度$\Delta A$的绝对值$|\Delta A|$的阈值曲线
Fig. 5. The strength threshold curve of absolute value $\left| {\Delta A} \right|$ of the second inhibitory impulsive current applied at different phase ($\Delta t)$ to evoke the second action potential