Primary afferent dendrite degeneration as a cause of tinnitus

• Published in: Journal of neuroscience research Vol. 85; no. 7; pp. 1489 - 1498
• Main Authors: Bauer, Carol A., Brozoski, Thomas J., Myers, Kristin
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 15.05.2007
• Subjects: Acoustic Stimulation; animal model; Animals; Auditory Pathways - pathology; Chronic Disease; cochlea; Cochlea - pathology; Dendrites - pathology; Disease Models, Animal; Hair Cells, Auditory - pathology; Male; Nerve Degeneration - pathology; neural degeneration; Rats; Rats, Long-Evans; tinnitus; Tinnitus - pathology
• ISSN: 0360-4012; 1097-4547
• DOI: 10.1002/jnr.21259

Chronic tinnitus affects millions of people, but the mechanisms responsible for the development of this abnormal sensory state remain poorly understood. This study examined the type and extent of cochlear damage that occurs after acoustic trauma sufficient to induce chronic tinnitus in rats. Tinnitus was evaluated by using a conditioned suppression method of behavioral testing. Cochlear damage was assessed 6 months after acoustic trauma. There was minimal loss of inner and outer hair cells in the exposed cochleas of subjects demonstrating evidence of tinnitus. However, a significant loss of large‐diameter fibers in the osseous spiral lamina of exposed cochleas of trauma subjects was observed. The significance of this finding in the context of a model of tinnitus is discussed. © 2007 Wiley‐Liss, Inc.