Hippocampal electrical activity was recorded from the dorsal hippocampus in rats during VI30" reinforcement schedule for food and during tone presentation followed by avoidable shock (group AV), inescapable shock (group IE), and no shock (group NS). Three groups of animals exhibited the different emotional levels. Group IE showed the great suppression of barpress in response to the tone CS. Group AV showed moderate suppression, and group NS was not suppressed to the tone. Group AV also learned avoidance running into the safety zone. Hippocampal rhythmical slow activity was associated with their barpress responses and avidance. It appears that hippocampal RSA correlates the initiation of operant behavior. Hippocampal auditory evoked potential increased the amplitude in progressive sessions for group IE. In group AV, it was not so larger as group IE. It suggests that auditory evoked potential reflects the significance of signal to animals.