Afferent Coding And Efferent Control In The Normal And Impaired Cochlea

The auditory nerve is the neural transmission channel linking the cochlea and brainstem. After spectral decomposition of acoustic signals along the basilar membrane, afferent fibers convey information to the cochlear nucleus with astounding temporal precision, whereas efferent fibers form part of a negative-feedback control circuit thought to modulate the gain of cochlear signal transduction. Single-fiber spike-based neurophysiological recording in the auditory nerve continues to offer invaluable insights on cochlear mechanics and peripheral neural coding of sounds. Much has been learned over the past two decades regarding the effects of cochlear damage on coding and the relationship between neurophysiological and perceptual phenomena in audition. Here, a conceptual review of auditory nerve physiology in normal and impaired hearing is presented, including both afferent and efferent functions. Important historical foundations are covered as well as the most recent and exciting developments. The aim is to link neurophysiological findings with their perceptual counterparts wherever possible and to provide the reader a framework in which to understand the neural underpinnings of the everyday perceptual difficulties faced by hearing-impaired listeners.