On the sensation of tone:
            Asymptotic and physical models of the ear.

                             by 

              Richard D. Rabbitt (U of U, Bioengineering)


             INSCC 110, 3:30pm  Monday, April 13, 1998


                          Abstract

The healthy human ear is capable of comfortably resolving sounds varying in
amplitude over ~5 orders of magnitude (0.0004 to 40 dyn/cm2 at 1,500 Hz)
and varying in frequency over ~3 orders of magnitude.  This impressive
performance draws, in part, from a highly developed fluid-structure
interaction which generates a frequency-dependent traveling wave within the
cochlea.  Electro-motility of hair cells further refines the shape of the
traveling wave in a way that enhances the dynamic range of the cochlea.
The net effect is that complex sounds are converted into frequency and
amplitude coded signals in real time and directly transmitted to the brain
via thousands of afferent nerves running in parallel.  The seminar will
focus on the role of wave propagation and fluid-structure interactions in
shaping neural signals through the pattern of spatio-temporal activation of
sensory hair cells.  Asymptotic models will be applied to describe acoustic
wave propagation within the ear canal, acoustic interaction with the
tympanic membrane and the mechanics of the cochlea.  The lecture will
conclude with a live demonstration of a physical model of the cochlea in
response to pure tones, speech and music.



Requests for preprints and reprints to: r.rabbitt@m.cc.utah.edu
This source can be found at http://www.math.utah.edu/applied-math/