Abstract
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 <sub>1</sub> - f <sub>2</sub> are plotted as isolevel contours against primary levels (L <sub>1</sub> , L <sub>2</sub> ) for various primary frequencies f <sub>1</sub> and f <sub>2</sub> (f <sub>1</sub> < f <sub>2</sub> ). The L <sub>1</sub> at which the DP reaches its maximum level increases as L <sub>2</sub> increases, and the slope of the "optimal" linear path decreases as f <sub>2</sub> / f <sub>1</sub> increases. When primary levels and f <sub>2</sub> are fixed, DP level is band passed against f <sub>1</sub> . In the presence of a suppressor, DP level generally decreases as suppressor level increases and as suppressor frequency gets closer to f <sub>2</sub> ; 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. © 2010 Acoustical Society of America.