[Inner ear cochlear processes]

The processes accompanying the propagation across the basilar membrane (BM) of waves from a wide-band sound signal have been analyzed by physical methods. Particular emphasis in placed on the fact that BM is a low frequency filter. The characteristics of wave envelope from each of the sinusoidal components of the signal are given. The use of a simple mechanical model makes it possible to explain an initial increase in these envelopes. The steep slope of the envelope in its terminal part is explained in terms of the lighthill hydrodynamic model of cochlea. This provides a theoretical basis for adequate description of the periphery of the ear analyzer, with allowance for the active role of external auditory hair cells (EHC). Further research is needed to solve the problem completely. This is dictated by the complexity of the oscillatory system (BM in the region of the critical layer of cochlea plus EHC) and by its interaction with the autoregulation system in the air analyzer, which is described elsewhere.