Shera, Christopher
Professor of Otolaryngology-Head and Neck Surgery
The peripheral auditory system transforms air-borne pressure waves into neural impulses that are interpreted by the brain as sound and speech. The cochlea of the inner ear is a snail-shaped electro-hydromechanical signal amplifier, frequency analyzer, and transducer with an astounding constellation of performance characteristics, including sensitivity to sub-atomic displacements with microsecond mechanical response times; wideband operation spanning three orders-of magnitude in frequency; and an input dynamic range of 120 dB, corresponding to a million-million-fold change in signal energy. All of this is achieved not with the latest silicon technology but by self-maintaining biological tissue, most of which is salty water. How does the ear do it? To address this question, we exploit the ear's curious ability to make sound while listening to sound.
