**12. Interplay between HB motility and electromotility in the OHC**

In previous theories of the cochlear amplification and selectivity sharpening the follow‐ ing hypotheses, about which type of motility is the prime mechanism of operation, were considered:


From the theoretical analysis performed by the author it follows that the correct choice is the third hypothesis, i.e., both mechanisms (HB motility and electromotility) are necessary to provide high sensitivity and sharp frequency selectivity in the mammalian cochlea. HB motil‐ ity and electromotility in isolation cannot provide simultaneously power amplification and selectivity sharpening.
