Tinnitus related to physiological changes in the auditory nerve in chronically noise-exposed mice

Abstract

Tinnitus is a pervasive auditory dysfunction affecting up to 10% of the adult population. The perception of ringing or hissing in the absence of a physical stimulus in one or both ears can be caused by acoustic trauma and other factors. Mice are a commonly used model for auditory disorders in humans, although the behavioral examination of tinnitus in mice has primarily been limited to reflexive measures involving inhibition of the acoustic startle by gaps in noise. Using an identification paradigm, we behaviorally tested whether mice show symptoms of tinnitus following long-term moderate noise exposure. Tinnitus was demonstrated by a shift in categorizing silence as narrowband noise. This experiment demonstrated that tinnitus can be induced in mice using noise exposure, similar to that caused by salicylate. Physiological and anatomical experiments reveal synaptic changes including response facilitation, increased reliability, increased synaptic terminal area, and increased number of release sites in mice ...