how the ear works

My respite from NSF proposals was a nice seminar by Tom Duke (UCL) about how the ear hears. He emphasized the amazing range of the ear: a factor of 1000 in frequency, and a factor of 10¹² in loudness. The faintest sounds are heard just at the thermal limit, ie, when the energy per cycle is about kT. He showed that the hair cells that do the heavy lifting are very dissipative objects but driven nonlinearly so as to act like incredibly sensitive oscillators, and that they transmit their information to the auditory nerve in the form of pulse distributions, or really the time delay distribution of delays between pulses. Incredible, all around.