Details

Autor(en) / Beteiligte

• Sedley, William

Titel

Tinnitus: Does Gain Explain?

Ist Teil von

• Neuroscience, 2019-05, Vol.407, p.213-228

Ort / Verlag

United States: Elsevier Ltd

Erscheinungsjahr

2019

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Many, or most, tinnitus models rely on increased central gain in the auditory pathway as all or part of the explanation, in that central auditory neurones deprived of their usual sensory input maintain homeostasis by increasing the rate at which they fire in response to any given strength of input, including amplifying spontaneous firing which forms the basis of tinnitus. However, dramatic gain changes occur in response to damage to the auditory periphery, irrespective of whether tinnitus occurs. This article considers gain in its broadest sense, summarizes its contributory processes, neural manifestations, behavioral effects, techniques for its measurement, pitfalls in attributing gain changes to tinnitus, a discussion of the minimum evidential requirements to implicate gain as a necessary and/or sufficient basis to explain tinnitus, and the extent of existing evidence in this regard. Overall there is compelling evidence that peripheral auditory insults induce changes in neuronal firing rates, synchrony and neurochemistry and thus increase gain, but specific attribution of these changes to tinnitus is generally hampered by the absence of hearing-matched human control groups or insult-exposed non-tinnitus animals. A few studies show changes specifically attributable to tinnitus at group level, but the limited attempts so far to classify individual subjects based on gain metrics have not proven successful. If gain turns out to be unnecessary or insufficient to cause tinnitus, candidate additional mechanisms include focused attention, resetting of sensory predictions, failure of sensory gating, altered sensory predictions, formation of pervasive memory traces and/or entry into global perceptual networks. This article is part of a Special Issue entitled: Hearing Loss, Tinnitus, Hyperacusis, Central Gain. •Gain changes comprise changes in synaptic properties, neuronal excitability and neural synchrony.•Dramatic gain changes, at all levels of the central auditory pathway, follow damage to the peripheral auditory system.•Lack of hearing-matched control groups has been the main factor preventing attribution of gain changes to tinnitus.•For gain to be a sufficient explanation of tinnitus, it must provide accurate classification at the individual subject level.•Alternative/additional processes are summarized to explain tinnitus if gain changes are non-contributory or insufficient.