Active Control in the
Cochlea
Mechanical
Engineering Department
University of
Michigan
The mammalian cochlea is a marvel of
micromechanical construction. This tiny organ is the central processor for
hearing. It separates the incoming
acoustic information in time and frequency for later processing by the brain in
a manner unrivaled by manmade
devices. It is now understood that
the exquisite frequency
selectivity, transient capture and dynamic range of the cochlear
response (which is, in turn,
imparted to mammalian
hearing) is made possible by a feedback mechanism further enabled by
electromotile proteins unique in biology.
The structure and function of the cochlea is briefly described along
with macroscopic mechanical-electrical-acoustic modeling techniques.
Constitutive models of the active motor proteins are given along with
experimental results documenting the unique function of these cells. Hypotheses for feedback mechanisms in
the cochlea will be presented along with a discussion of how biology might
achieve cycle-by-cycle feedback at frequencies from 5kHz to 60kHz. Our efforts at building a cochlear
analog transducer using micromachining techniques will also be discussed.
3:30 – 4:30
p.m.