Program of Research
Work cited:
Bauer CA, Brozoski TJ, Rojas R, Boley J, Wyder M (1999). “Behavioral model of chronic tinnitus in rats.” Otolaryngology – Head and Neck Surgery, 121 (4), 457-462.
Summary:
Present study induced tinnitus in rats with salicylate (known to produce tinnitus in humans). Given sodium salicylate in their water and conditioned to press a lever for food in the presence of continuous white noise. Results indicated that the experimental subjects could detect the tone stimuli and weren't hearing impaired. Conclude that rats, under the proper condition, perform in an auditory discrimination task as though they had tinnitus.
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Work cited:
Brozoski TJ, Bauer CA (2005). “The effect of dorsal cochlear nucleus ablation on tinnitus in rats.” Hearing Research, 206, 227-236.
Summary:
Present study investigates the hypothesis that the rostral output of the DCN is necessary for the experience of chronic tinnitus by ablating the dorsal DCN and the dorsal acoustic stria of rats with psychophysical evidence of tinnitus. Ablating the DCN should decrease the evidence of tinnitus, if the DCN plays a role in chronic tinnitus. However, bilateral dorsal DCN ablation didn't significantly affect the psychophysical evidence of tinnitus, and ipsilateral dorsal DCN ablation appeared to increase the evidence of tinnitus. Results showed that the DCN doesn't act as a simple feed forward source of chronic tinnitus.
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Work Cited:
Brozoski TJ, Ciobanu L, Bauer CA (2007). “Central neural activity in rats with tinnitus evaluated with manganese-enhanced magnetic resonance imaging (MEMRI).” Hearing Research, 228, 168-179.
Summary:
Incorporation of vigabatrin (a GABA agonist) into the drinking water of rats with acoustic trauma induced chronic tinnitus eliminated the psychophysical evidence of chronic tinnitus. Present study also demonstrated that elevation of central GABA levels effectively counteracted tinnitus.
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Work Cited:
Brozoski TJ, Caspary DM, Bauer CA, Richardson BD (2010). “The effect of supplemental dietary Taurine on tinnitus and auditory discrimination in an animal model.” Hearing Research, 270, 71-80.
Summary:
Present study adds taurine (partial agonist at inhibitory glycine and y-amino butyric acid receptors) to the daily diet of rats to examine its effects on chronic tinnitus and normal auditory discrimination. Rats were trained and tested in an operant task shown to be sensitive to tinnitus. Results show that high taurine dose significantly attenuated tinnitus, which returned to near pre-treatment levels following washout. Results were consistent with hypothesis that taurine attenuates tinnitus and improves auditory discrimination by increasing inhibitory tone and decreasing noise in the auditory pathway.
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Work Cited:
Wang H, Brozoski TJ, Caspary DM (2011). “Inhibitory neurotransmission in animal models of tinnitus: Maladaptive plasticity.” Hearing Research, 279, 111-117.
Summary:
Review examines evidence for chronic plastic neuropathic changes in the central auditory system of animals with psychophysically defined tinnitus.
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Work Cited:
Brozoski TJ, Wisner KW, Sybert LT, Bauer CA (2012). “Bilateral Dorsal Cochlear Nucleus Lesions Prevent Acoustic-Trauma Induced Tinnitus in an Animal Model.” Journal of the Association for Research in Otolaryngology, 13, 55-66.
Summary:
Present study investigated DCN (dorsal cochlear nucleus) ablation to reduce tinnitus in animal models. DCN presents with abnormally elevated spontaneous neural activity of animals with tinnitus. Present study failed to decrease pre-existing tinnitus and believes DCN may serve as a trigger zone rather than a chronic generator of tinnitus. This trigger mechanism may involve plastic circuits that increase spontaneous neural output to rostral areas like the inferior colliculus. This increased drive could produce persistent pathological changes in the rostral areas that comprise the tinnitus signal.
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Work Cited:
Bauer CA, Kurt W, Sybert LT, Brozoski TJ (2013). “The cerebellum as a novel tinnitus generator.” Hearing Research, 295, 130-139.
Summary:
A series of experiments examining the role of the cerebellum in trauma-induced tinnitus. PFL (paraflocculus of the cerebellum) was surgically ablated in animals before the induction of tinnitus. It was found that PFL ablation eliminated established tinnitus without altering auditory discrimination. However, PFL ablation before tinnitus induction attenuated, but didn't completely eliminate tinnitus.
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