Critical Regimes in the Mammalian Cochlea Ex Vivo

The mammalian cochlea benefits from an active process characterized by amplification of mechanical inputs, sharp frequency selectivity, compressive nonlinearity, and spontaneous otoacoustic emission. Similar traits are observed in individual hair cells of nonmammalian tetrapods, in which they emerge from the critical dynamical regime of hair cells operating near a Hopf bifurcation. It remains unclear whether a similar critical regime also underpins the active process of the mammalian cochlea. Efforts to address this question have been limited in part by the absence of an ex vivo preparation that both preserves the physiological integrity of the sensory epithelium and grants direct experimental access to it.