An integrative model of tinnitus based on a central gain controlling neural sensitivity.

Summary

This review proposes the model linking hearing loss to the phantom perception of tinnitus. Cochlear injury reduces activity in the cochlear nerve, yet neural activity is increased at virtually every level of the central auditory system. Noreña argues this central hyperactivity results from a central gain increase whose purpose is to adapt sensitivity to reduced input, preserving a stable mean firing rate and coding efficiency. The price of maintaining that homeostasis is amplification of 'neural noise' along with the signal, ultimately generating tinnitus.

Key findings

• Cochlear injury reduces auditory-nerve activity, yet activity is increased at virtually all levels of the central auditory system.
• Proposes central gain increase as a homeostatic adaptation preserving stable mean firing and coding efficiency.
• The cost of that homeostasis is amplified 'neural noise', which can be perceived as tinnitus.
• Sets out the clinical implications of a gain-based account of tinnitus.