Overt and covert paths for sound in the auditory system of mammals

TL;DR

This paper proposes a bioelectronic 'covert' pathway in mammals' auditory system, supplementing the mechanical 'overt' path, to explain high-frequency hearing and related impairments.

Contribution

It introduces experimental evidence for a bioelectronic pathway involving piezoelectric potentials, expanding the classical mechanical theory of sound transmission in mammals.

Findings

Tympanum produces piezoelectric potentials synchronized with vibrations.

Amplitude of potentials increases with frequency and vibration level.

Deficiencies in this pathway are linked to hearing impairments.

Abstract

Current scientific consensus holds that sound is transmitted, solely mechanically, from the tympanum to the cochlea via ossicles. But this theory does not explain the hearing extreme quality regarding high frequencies in mammals. So, we propose a bioelectronic pathway (the covert path) that is complementary to the overt path.. We demonstrate experimentally that the tympanum produces piezoelectric potentials isochronous to acoustic vibrations thanks to its collagen fibers and that their amplitude increases along with the frequency and level of the vibrations. This finding supports the existence of an electrical pathway, specialized in transmitting high-frequency sounds, that works in unison with the mechanical pathway. A bio-organic triode, similar to a field effect transistor, is the key mechanism of our hypothesized pathway. We present evidence that any deficiency along this pathway produces hearing impairment. By augmenting the classical theory of sound transmission, our discovery offers new perspectives for research into both normal and pathological audition and may contribute to an understanding of genetic and physiological problems of hearing.