Josef J. Zwislocki Inst. for Sensory Res., Syracuse Univ.,
Syracuse, NY 13244-5290 There are several areas of hot topics in
physiological acoustics. However, from the point of view of
acoustics, the cochlea that both transmits sound and transduces
it into electrochemical events that initiate the digitized
neural code must be the closest to an acoustician's heart. The
cochlea has been a hot topic since the discovery in the late
60's that a live cochlea acted in a different way from a passive
post-mortem one. Subsequent discoveries revealed that it was
able to emit sound and that its mechano-electrical transducers
of one type, the outer hair cells, were bidirectional and also
acted as electromechanical transducers, providing in this way a
feedback loop. Now it has been found that neither the cochlear
transfer functions nor its input--output functions are
invariant, but that they change with the intensity and duration
of sound. These nonlinear dynamics suggest explanations for the
nonlinear growth of loudness wi