A model of cochlear mechanics is described in which force-producing outer hair cells (OHC) are embedded in a passive cochlear partition. The OHC mechanoelectrical transduction current is nonlinearly modulated by reticular-lamina (RL) motion, and the resulting change in OHC membrane voltage produces contraction between the RL and the basilar membrane (BM). Model parameters were chosen to produce a tonotopic map typical of a human cochlea. Time-domain simulations showed compressive BM displacement responses typical of mammalian cochleae. Distortion product (DP) otoacoustic emissions at 2 f 1 - f2 are plotted as isolevel contours against primary levels (L1, L2) for various primary frequencies f 1 and f2 (f1 < f2). The L 1 at which the DP reaches its maximum level increases as L 2 increases, and the slope of the "optimal" linear path decreases as f2 / f1 increases. When primary levels and f2 are fixed, DP level is band passed against f1. In the presence of a suppressor, DP level generally decreases as suppressor level increases and as suppressor frequency gets closer to f2; however, there are exceptions. These results, being similar to data from human ears, suggest that the model could be used for testing hypotheses regarding DP generation and propagation in human cochleae.
ASJC Scopus subject areas
- Arts and Humanities (miscellaneous)
- Acoustics and Ultrasonics