Temporal pattern of prothoracic auditory interneurone response during downward (left) and upward (right) stepwise change of stumulus amplitude. The preparation was stimulated with a pulse train (pulse duration 5 ms, stimulation period 40 ms, carrier frequency 100 kHz). Stimulus amplitude (peak value) is given in dB SPL (vertical axis). Each dot represents a single spike. Time from the stimulus (pulse) onset is given in ms (horizontal axis). Each amplitude step equal to 1 dB included 40 stimulus presentations.