Figure 3

Noise-exposed animals show elevated Hyperacusis Indices (HI) compared to controls. (A) HI, shown for two example RIFs, was calculated from the geometric mean of: 1) the average RIF slope from 40–90 dB (dashed black line) and 2) peak firing rates over the same intensity interval (orange star). (B) HI vs BF for noise-exposed animals (warm color, filled, square symbols) and non-exposed controls (cool color, open, diamond symbols) relative to the noise-exposure spectrum (black triangle with grey background). Hyperacusis threshold shown as dashed black line; each color denotes data the same animal. (C) Threshold-triggered mean spike waveforms were identified from single units with a range of HI values (inset text) and from noise-exposure status (upper panels: controls in black; lower panels: noise-exposed in purple). Single-unit spike waveforms not distinguished by HI or noise-exposure status. For each waveform, N >  = 20 spike snippets included. Data shown are mean + /-SEM. (D) Left panel: SFR by BF for Hyperacusis units, with distribution mean (orange line). Right panel: SFR by BF for non-Hyperacusis units, with distribution mean (orange line). (E) HI versus SFR, with Hyperacusis-unit clusters indicated by orange ellipses. Hyperacusis threshold line shown in orange. (F) Monotonic fraction of a unit (100-nMF%) plotted with the unit’s HI. Hyperacusis Threshold (HI = 35.5) shown (solid, vertical orange line).