Modulation of the hair cell motor: a possible source of odd-order distortion

A recent paper by Nuttall and Dolan [J. Acoust. Soc. Am. 93, 2061-2068 (1993)] on intermodulation distortion in the cochlea concluded that electrical quadratic distortion (f2-f1) came predominantly from inner hair cells (IHCs). However, they suggested that the outer hair cells provided the mechanical input that caused this even-order distortion. The data reported here describe the nonlinear components in the gross electrical and acoustic emission responses of the gerbil and suggest a mechanism by which odd-order distortion could be generated by modulation of the fast phasic motile response of outer hair cells (OHCs) by the even-order distortion signal.