Figure 7.

Four pulses separated by inter stimulus interval of 2 ms forming a quadripulse burst [36]. The plots show (a) measured electric field waveform E (filtered with 3-point median filter to illustrate clearly pulse amplitude by removing switching spikes) and (b) estimated neural membrane depolarization ΔV_m. The initial capacitor voltages are V_C11 = 1230 V and V_C21 =0.22V_C11, and the duration of the first, negative phase of the electric field pulses is fixed at 200 µs. In order to compensate for the reduction of charge on the capacitors due to energy loss and the consequent reduction of pulse amplitude, the duration of the second, positive electric field phase is increased for each subsequent pulse, having values of 67, 69, 73, and 78 µs, respectively.