High-side two-tone suppression is lost while low-side suppression survives outer-hair-cell damage.

Evidence

Previous studies have examined the relationship between ANF 2TS and chronic low-level noise exposure coupled with ageing in the Mongolian gerbil (Schmiedt et al. 1990 ; Schmiedt and Schultz 1992 ), and following an acute intense noise exposure in the cat (Miller et al. 1997 ). Ageing in a noisy environment was associated with a loss of 2TS. Schmiedt and colleagues often found complete absence of high-side 2TS, with sparing of low-side 2TS, even in cochlear regions with up to 60 % outer-hair-cell loss; suggesting potentially different mechanisms for lowand high-side suppression. Our 2TS data are in broad agreement with these earlier findings: HI chinchillas had elevated high-side 2TS thresholds, but retained sensitivity to low-side suppressors. Miller et al. ( 1997 ) related a reduction in 2TS in ANFs to changes in the representation of voiced vowel sounds. Weakened compressive nonlinearities contributed to a reduction in “synchrony capture” by stimulus harmonics near vowel-formant peaks. — Dijk, Pim van, Physiology, Psychoacoustics and…, 3877

Categorization

• QUESTION: What could explain the selective vulnerability of high-side suppression? The authors explicitly flag potentially different low- vs. high-side mechanisms.
• XREF: Connects to the reader’s broader interest in compressive nonlinearity and cochlear amplification mechanics.