Electronic Thesis and Dissertation Repository


Master of Science


Anatomy and Cell Biology


Dr. Brian L. Allman


Subjective tinnitus is characterized as the perception of a phantom sound with no external acoustic source, and is often described as a “ringing in the ears” sensation. While evidence supports a central origin for tinnitus, the underlying neural mechanisms for this condition remain elusive. The studies presented in this thesis offer significant contributions to understanding the neural basis of tinnitus by (1) validating a behavioural paradigm that can successfully screen rats for transient noise-induced tinnitus without any indications of false-positives, and (2) demonstrating that a local loss of inhibition is sufficient to induce gain enhancement in the primary auditory cortex, as well as tinnitus-positive behaviour - evidence that supports the central gain model, one of the leading hypotheses of tinnitus generation. Overall, these findings help provide more effective strategies to directly investigate putative mechanisms of tinnitus, and furthermore expand our current understanding of this distressing condition.