Extended Data Fig. 3: Tuning curve peaks (best frequencies) are identifiable as the tested frequency range is extended at lower amplitudes and maximum SSI is conveyed at the peaks of the tuning curves.

a, Frequency tuning of four example neurons at amplitude 5.45 µm that appear to show monotonic or saturating increases. b, When tested over a wider frequency range at attenuated amplitudes, these neurons also show frequency-selective tuning. Top, middle and bottom panels are tuning curves of the same five example neurons tested at vibration amplitudes of 5.45 µm, 1.08 µm and 0.23 µm, respectively. c, Frequency-tuned responses of three representative neurons (bottom) tested at the indicated vibration amplitudes. Their respective bias-corrected SSI (top) shows information maxima at the tuning curve peaks (*P < 0.01, permutation test). d, Normalized tuned responses (grey) and their mean (red) of frequency-selective neurons across the three amplitudes (n = 548) aligned to their best frequency (bottom) and the corresponding significant SSI values (grey squares), their mean (black line) and their proportions (red circle sizes) relative to the total number of neurons (top). All other symbols are as in Fig. 1.