Cochlear Mechanics

The field of cochlear mechanics has received an increasing interest over the last few decades. In the majority of these studies the researchers use linear systems analysis or linear approximations of the nonlinear (NL) systems. Even though it has been clear that the intact cochlea operates nonlinearly, lack of tools for proper nonlinear analysis, and widely available tools for linear analysis still lead to inefficient and possibly incorrect interpretation of the biophysics of the cochlea. An example is the presumption that a change in cochlear stiffness at hair cell level must account for the observed change in tuning (or frequency mapping) due to prestin application. Hypotheses like this need to be addressed in a tutorial that is lucid enough to analyze and explain basic differences. Cochlear Mechanics presents a useful and mathematically justified/justifiable approach in the main part of the text, an approach that will be elucidated with clear examples. The book will be useful to scientists in auditory neuroscience, as well as graduate students in biophysics/biomedical engineering.

This book extends our understanding of the mechanics and biophysics of hearing by bringing together the latest research on the topic by experts in cell and molecular biology, physiology, physics, engineering and mathematics. It contains the proceedings of the 10th International Workshop on the Mechanics of Hearing that was held at Keele University in the United Kingdom at the end of July, 2008. Topics for discussion included theoretical and experimental research at the molecular, cellular and systems levels. Separate sections of the book deal with: the transmission of sound energy to and from the inner ear, and wave propagation within the inner ear; the enhancement of stimulus wave motion that occurs in the inner ear; new measurement techniques that will underpin future innovative studies; the micro-mechanics of the basilar and tectorial membranes and the organ of Corti; cochlear dynamics; sensory hair cells and electromechanical transduction; and sensory hair-bundles and mechano-electrical transduction. The book concludes with the transcript of an open discussion session between the participants of the workshop, highlighting areas of uncertainty and controversy in the field, and pointing the way to the solutions to be sought in future research. This book reviews and synthesizes current concepts and challenges in the biophysics of hearing, and will be an invaluable guide to researchers and students in all branches of auditory science.

IUTAM/ICA Symposium, Delft, July 1983

This special issue collects our current knowledge of the mechanical processing of acoustic signals by the cochlea and its containing structures. Many workers in diverse disciplines in otology use the facts from cochlear mechanics for the interpretation of their results. Presented here for the first time is the development of a three-dimensional mechanical model of the curved cochlea including fluid-structure couplings. An important approach for future cochlear modeling is shown by the provision of geometrical data for the input of three-dimensional finite element models by microtomographic imaging. A remarkable article tries to demonstrate a connection between outer hair cell mechanics and the complex phenomenon of tinnitus and will be of special interest for stress engineers. Owing to its strong interdisciplinarity, this issue is not only intended for biophysicists, ENT clinicians and audiologists but also for radiologists, biomechanical engineers and computer engineers.

Great advances have been made in understanding hearing in recent years. In particular, the mechanical function of the cochlea has become the focus of intense interest. This started in one direction, with the discovery of otoacoustic emissions in 1978, which required active mechanical amplification processes, as first postulated by Gold in 1948. Direct evidence for the role of this mechanism in sharpening-up the otherwise poor, basilar membrane tuning properties, was provided in 1982; and in 1983, motility was shown in outer hair cells. In parallel, an immense amount of work has been done on the electrophysiology of hair cells, following the first intracellular recordings in 1977. Over a longer time scale, models of basilar membrane motion have been developed and refined, and recently much effort has been put into incorporating active mechanisms and non-linear processes. It seemed an opportune time to bring together the leading workers in these various areas, to take stock of the whole field and to stimulate further progress. This book represents the proceedings of a NATO ARW on the Mechanics of Hearing held at the University of Keele, 3-8 July, 1988. The conception of the meeting owes much to earlier meetings held in Boston in 1985 (Peripheral Auditory Mechallisms, Eds. J.B. Allen, J.L.

This monograph is focussed onto the sensory consonance of two simultaneous complex tones. Part One describes psycho-acoustic consonance experiments undertaken by the author and by several earlier researchers. Some of these experiments were informal one-man studies, while others involved fairly large groups of subjects and subsequent statistical analysis. Part Two contains selected chapters of cochlear mechanics. In Part Three, the consonance theory of Hermann von Helmholtz is briefly discussed, and an addition to that theory, first published by the author in 2001, is described. The present volume is intended to add weight to the hypothesis that our preference for certain two-tones (e.g., for major or minor thirds at female-singing pitch, or for perfect fifths at bass pitch) is not only due to education, but is based on the physiology of our hearing organs. The readers are expected to know biology, physics, and mathematics at high-school level. Exercises and their solutions are included at the end of most sections.

Proceedings of a workshop on the physics and biophysics of hearing that brought together experimenters and modelers working on all aspects of audition. Topics covered include: cochlear mechanical measurements, cochlear models, mechanicals and biophysics of hair cells, efferent control, and ultrastructure.

This proceedings volume contains papers presented during the meeting on Diversity in Auditory Mechanics by leading neurobiologists, biophysicists and mathematicians interested in auditory periphery.