Offset responses to harmonic tone stimulation are more robust in AAF than in A1. (a) Raster plot of an example A1 (top-left) and AAF (top-right) neuron’s response to HTs (9 + 18 + 27 + 36 kHz) played at 60 dB SPL with sound duration varying between 50 and 500 ms and ISI between 50 and 2000 ms and (bottom) PSTH (mean ± SD) averaged over all neurons. The blue shaded bars represent the tone presentation. The example neurons do not correspond to those presented in Fig. 2a. (b) Comparison of strength of onset and offset responses in A1 and AAF neurons for 500 ms HTs (9 + 18 + 27 + 36 kHz) played with 2000 ms ISIs. Responses are color-coded to the onset BFs. (c) A1 (left) and AAF (right) offset responses to HTs (9 + 18 + 27 + 36 kHz) with increasing duration across all ISIs’ (correlation between sound duration and response rate: A1, ρ = 0.0857, p = 0.9194, n = 191; AAF, ρ = 1, p = 0.0028, n = 190, Spearman correlation). (d) Ratio of offset/onset responses in A1 and AAF for HTs (9 + 18 + 27 + 36 kHz) with varying durations (50–500 ms) and 2000 ms ISI. Data represent mean ± SEM. ****p < 0.0001, **p = 0.0031, Mann-Whitney test.