Mechanisms of Synaptic Plasticity in the Dorsal Cochlear Nucleus: Plasticity-Induced Changes That Could Underlie Tinnitus Purpose Tinnitus is the persistent perception of a subjective sound. Tinnitus is almost universally experienced in some forms. In most cases, recovery may occur in seconds, hours, or days. How does tinnitus shift from a transient condition to a lifelong disorder? Several lines of evidence, including clinical studies and animal ... Supplement Article
Supplement Article  |   December 01, 2008
Mechanisms of Synaptic Plasticity in the Dorsal Cochlear Nucleus: Plasticity-Induced Changes That Could Underlie Tinnitus
 
Author Affiliations & Notes
  • Thanos Tzounopoulos
    Chicago Medical School, Rosalind Franklin University, North Chicago, IL
  • Contact author: Thanos Tzounopoulos, who is now at the Department of Otolaryngology, University of Pittsburgh School of Medicine, 203 Lothrop Street, Eye and Ear Institute, Room 152, Pittsburgh, PA 15213-2588. E-mail: thanos@pitt.edu.
Article Information
Hearing Disorders / Supplement: Tinnitus
Supplement Article   |   December 01, 2008
Mechanisms of Synaptic Plasticity in the Dorsal Cochlear Nucleus: Plasticity-Induced Changes That Could Underlie Tinnitus
American Journal of Audiology, December 2008, Vol. 17, S170-S175. doi:10.1044/1059-0889(2008/07-0030)
History: Received August 1, 2007 , Accepted November 8, 2007
 
American Journal of Audiology, December 2008, Vol. 17, S170-S175. doi:10.1044/1059-0889(2008/07-0030)
History: Received August 1, 2007; Accepted November 8, 2007
Web of Science® Times Cited: 28

Purpose Tinnitus is the persistent perception of a subjective sound. Tinnitus is almost universally experienced in some forms. In most cases, recovery may occur in seconds, hours, or days. How does tinnitus shift from a transient condition to a lifelong disorder? Several lines of evidence, including clinical studies and animal models, indicate that the brain, rather than the inner ear, may in some cases be the site of maintenance of tinnitus. One hypothesis is that normal electrical activity in the auditory system becomes pathologically persistent due to plasticity-like mechanisms that can lead to long-term changes in the communication between neurons. A candidate site for the expression of this so-called synaptic plasticity is a region of the brainstem called the dorsal cochlear nucleus (DCN), a site of integration of acoustic and multimodal, sensory inputs.

Conclusions Here we review recent findings on cellular mechanisms observed in the DCN that can lead to long-term changes in the synaptic strength between different neurons in the DCN. These cellular mechanisms could provide candidate signaling pathways underlying the induction (ignition) and/or the expression (maintenance) of tinnitus.

Acknowledgments
I thank Drs. Jeremy Turner, Donald Caspary, Susan Shore, and Maria Rubio for helpful comments and discussions. This work was supported by National Institutes of Health Grant R01 DC 007905-01A1.
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