The neuroscience of hearing or how to do a hard job with soft components.

The inner ear is a small and relatively inaccessible structure. The use of multiple biophysical recording techniques from the late 1970s onwards, combined with molecular genetics to identify genes critically involved in cochlear development, has revealed how the cochlea acts as the front end for the central nervous system analysis of the auditory world. Some notable progress has been made in clarifying the mechanisms of frequency coding and cochlear amplification, and of mechano-transduction in hair cells and in establishing molecules necessary for normal (and by implication in abnormal) development of hearing and balance. There has been a parallel growth in understanding some of the neural networks in the brainstem and cortical areas responsible for processing the information derived from the auditory nerve. Informing future technical improvements to hearing aids and cochlear implants (electrically and optogenetically encoded), this chapter concentrates mainly on the neuroscience of peripheral hearing.