Role of Auditory Cortex in Noise- and Drug-Induced Tinnitus Purpose To elucidate the role of auditory cortex in tinnitus. Method Neurophysiological findings in cat auditory cortex following noise trauma or the application of salicylate and quinine, all expected to induce tinnitus, were reviewed. Those findings were interpreted in the context of what is expected from studies in ... Supplement Article
Supplement Article  |   December 01, 2008
Role of Auditory Cortex in Noise- and Drug-Induced Tinnitus
 
Author Affiliations & Notes
  • Jos J. Eggermont
    University of Calgary, Calgary, Alberta, Canada
  • Contact author: Jos J. Eggermont, Department of Psychology, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada. E-mail: eggermon@ucalgary.ca.
Article Information
Hearing & Speech Perception / Hearing Disorders / Supplement: Tinnitus
Supplement Article   |   December 01, 2008
Role of Auditory Cortex in Noise- and Drug-Induced Tinnitus
American Journal of Audiology, December 2008, Vol. 17, S162-S169. doi:10.1044/1059-0889(2008/07-0025)
History: Received July 5, 2007 , Accepted August 3, 2007
 
American Journal of Audiology, December 2008, Vol. 17, S162-S169. doi:10.1044/1059-0889(2008/07-0025)
History: Received July 5, 2007; Accepted August 3, 2007
Web of Science® Times Cited: 24

Purpose To elucidate the role of auditory cortex in tinnitus.

Method Neurophysiological findings in cat auditory cortex following noise trauma or the application of salicylate and quinine, all expected to induce tinnitus, were reviewed. Those findings were interpreted in the context of what is expected from studies in humans, specifically in the brains of people with tinnitus.

Results Tinnitus is an auditory percept to which several central structures in the auditory system may contribute. Because the central auditory system has both feed-forward connections and feedback connections, it can be described as a set of nested loops. Once these loops become activated in a pathological fashion, as they may be in tinnitus, it becomes hard to assign importance to each contributing structure. Strongly interconnected networks, that is, neural assemblies, may be determining the quality of the tinnitus percept.

Conclusion It is unlikely that tinnitus is the expression of a set of independently firing neurons, and more likely that it is the result of a pathologically increased synchrony between sets of neurons. There is clear evidence for this from both evoked potentials and from neuron-pair synchrony measures.

Acknowledgments
This work was supported by the Alberta Heritage Foundation for Medical Research, the National Sciences and Engineering Research Council of Canada, a Canadian Institutes of Health-New Emerging Team grant, and the Campbell McLaurin Chair for Hearing Deficiencies.
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