The efficiency of the cytoarchitecture of the organ of Corti for active cochlear amplification

A “Y”-shaped structure of cells formed by the basally tilted force generating outer hair cells (OHC) and apically tilted passive phalangeal process (PhP) connected to a Deiter cell (DC) has been hypothesized to be an essential organ of Corti (OoC) building block for cochlear amplification (Yoon et al., 2011). We developed a COMSOL finite-element model of the mouse cochlea, taking into account the spatial arrangement of Y-shaped elements and the 3-D fluid-structure interaction. The model was validated by comparison with previously reported basilar membrane (BM) displacement for both passive and active cases (Lee et al., 2015). The baseline model can reproduce an increase of 40 dB gain of the BM (re stapes velocity) for low level sounds. However, the absence of the PhP results in an unstable response of the BM for active cases. The model with the roles of the PhP and OHC switched, could not reproduce the active gain. Finally, the model with reversed titling orientation of OHC and PhP cells generated signifi...