The Peripheral Hearing Mechanism: A Biochemical and Biological Approach

Abstract

A new approach is described to the problem of hearing at energy levels near threshold. Models depending on the macro-physics of levers are rejected. Instead, evidence is presented for frequency analysis, signal placement and energy transduction by the properties (known or experimentally determined) of the cochlea and of the structures within the scala media. The hypothesis developed rests on the established theorems of Gabor and Brillouin, and at the same time is based on the data of enzymology. Care is taken not only that the hypothesis does not conflict but that it is actually consonant with recent solid state physics. The cochlea by virtue of its internal geometry and contained column of fluid is considered to perform a Fourier analysis to a first approximation. This crude “placement” of the acoustic signal is refined by the semi-solid-state lattice of the tectorial membrane which far from permitting dissipation of the signal energy actually “concentrates” the energy at the membrane surface of the hair processes of a hair cell. Here biochemical transduction, akin to the processes known for other sensory cells, transforms acoustic energy through an ion-shuttling mechanism to the form of energy characteristic of living cells, viz. enzyme conformational changes.