Revealing the contribution of basilar membrane’s biological activity to the mechanism of the cochlear phonosensitive amplification

Explaining the mechanism of the cochlear active phonosensitive amplification has been a major problem in medicine. The basilar membrane (BM) is the key infrastructure. In 1960, Nobel Laureate von Békésy first discovered BM’s traveling wave motion. Since that time, BM’s models only have considered the traveling wave but not the biological activity. Therefore, a new model considering changes of BM’s stiffness in space and time is established based on the immersed boundary method to describe its biological activity. It not only reproduces the results of traveling wave motion but also explains the mechanization on the generation of traveling wave. An important discovery is that changes of BM’s stiffness in space and time will cause the unstable global resonance, which will induce amplification of sounds in cochlea. An important inference is that biological activity shall be included in the application of mechanical principles to the analysis of life, which is the essential difference between biomechanics and general mechanics.