A linear cochlear model with active bi-directional coupling

We present a linear active cochlear model that includes the outer hair cell (OHC) forces, which are delivered onto upstream and downstream basilar membrane (BM) segments through Deiters´ cells (DCs) and their phalangeal processes (PhPs). Due to the longitudinal tilt of the OHC towards the base and the oblique orientation of the PhP towards the apex, each BM segment receives both feed-forward and feed-backward OHC forces. Transverse BM fibers are actively coupled longitudinally through these bi-directional OHC forces, included in a cochlear model for the first time. We present simulation results that demonstrate large amplification and sharp tuning, and we analyze the underlying mechanism.