Electronic Thesis and Dissertation Repository


Master of Science


Anatomy and Cell Biology


Dr. Brian L. Allman


Abnormal cortical oscillations have been implicated in tinnitus generation. To gain further insight into this relationship, we performed two Experimental Series, both employing behavioural, pharmacological, and in vivo electrophysiological techniques in an animal model. To that end, we revealed three novel findings: (1) While exposure to 250 mg/kg sodium salicylate or transient loud noise induced behavioural evidence of tinnitus, these insults caused dissimilar effects on spontaneous cortical oscillations; (2) Despite these dissimilar effects, sodium salicylate and loud noise exposure caused similar deficits in the evoked oscillatory activity elicited by the auditory steady state response; and (3) Manipulation of medial geniculate body GABAergic inhibition is sufficient to alter spontaneous cortical oscillations, but does not induce tinnitus-like behaviour. Collectively, these findings suggest that there is no clear link between altered cortical oscillations and tinnitus, and the 40 Hz ASSR might be a useful tool for assessing the presence of tinnitus in animals.