Behavioral model of chronic tinnitus in rats

An animal model of tinnitus was developed to study chronic salicylate-induc ed tinnitus in rats. Novel features of the model included oral dosing of sa licylate, test stimuli that included a range of pure tones and silence, and assessment of tinnitus for several months. Experimental subjects were give n sodium salicylate in their drinking water while control subjects received normal tap water. Subjects were conditioned to press a lever for food in t he presence of continuous white noise. At random intervals, offset of the n oise was paired with a noxious stimulus, resulting in cessation of lever pr essing during the silent test periods. At other randomly scheduled interval s, a test tone was substituted for the white noise, unpaired with noxious s timuli. When the test stimuli were pure tones, the salicylate-treated subje cts suppressed less than the control subjects. One explanation for this res ult is that the experimental subjects' sensations of tones were noisier tha n those of the controls because experimental subjects were experiencing tin nitus.