Figure 2.

Morphology of different burst waveforms used in experiments. Each burst waveform uses 5 square leading-phase pulses of 1 ms duration separated by 1 ms and delivered at a 40 Hz repetition rate (also known as the intraburst frequency). The name of each burst waveform delineates the form of electrode charge recovery: (top) asymmetric biphasically–recharged burst (AB) recovers the electrode charge following each leading-phase pulse using an asymmetric equal-charge recovery waveform; (bottom) passively-recharged burst (PB) delays charge recovery until all five leading phase pulses have been delivered. The charge recovery waveform morphology was intended to grossly mimic the classic capacitive-discharge recovery waveform, as known from typical neurostimulators [15]. Example waveforms with amplitudes of 5 mA are shown.