May 2009

Document Type


Degree Name



Dept. of Physiology and Pharmacology


Oregon Health & Science University


The purpose of this dissertation is to study the role of neuronal synchrony and high frequency oscillations in perceptual processing in the auditory cortex of awake behaving rats. In order to do so, I first characterized these oscillations in the primary auditory cortex of rats passively listening to tones. After finding the high frequency oscillations are induced by auditory stimulus in the passively listening rats, I then proceeded to correlate these oscillations with meaningful simple tone patterns. I trained rats in a two-tone discrimination paradigm in which they had to perceive that two successive acoustic events signaled a reward. Moreover, because these two-tones were played in a fast temporal succession, which is commonly seen in a variety of animal vocalizations, the data produced can, in principle, indicate time processing properties of the auditory cortex. The experimental data gathered in this thesis strongly suggest that high frequency oscillations at gamma and high gamma ranges are modulated by auditory perception. I will show in Chapter 1 that tones induce high frequency oscillations. Then, in subsequent chapters (chapters 3 and 5), I will demonstrate that these oscillations are modulated by attention-related processes involved in auditory processing.




School of Medicine



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