Cubic and quadratic distortion products in vibrations of the mouse cochlear apex

When the ear is stimulated by two tones presented at frequencies f(1) and f(2), nonlinearity in the cochlea's vibratory response leads to the generation of distortion products (DPs), with the cubic 2f(1)–f(2) DP commonly viewed as the most prominent. While the quadratic f(2)–f(1) DP is also evident in numerous physiological and perceptual studies, its presence in the cochlea's mechanical response has been less well documented. Here, examination of vibratory DPs within the mouse cochlea confirmed that f(2)–f(1) was a significant and sometimes dominant component, whether DPs were measured near their generation site, or after having propagated from more basal locations.