  Cochlea displays complex and highly nonlinear behavior in response to
wide-ranging auditory stimuli. While there have been many recent advancements
in the modeling of cochlear dynamics, it remains unclear what mathematical
structures underlie the essential features of the extended cochlea. We
construct a dynamical system consisting of a series of strongly coupled
critical oscillators to show that high-dimensional nonhyperbolic dynamics can
account for high-order compressive nonlinearities, amplification of weak input,
frequency selectivity, and traveling waves of activity. As a single Hopf
bifurcation generically gives rise to features of cochlea at a local level, the
nonhyperbolicity mechanism proposed in this paper can be seen as a
higher-dimensional analogue for the entire extended cochlea.

Biological Physics;Neurons and Cognition