Taming in wild rats following medial amygdaloid lesions

Flight behavior, startle reactions, and defensiveness to nonpainful stimuli were examined before and after medial amygdaloid lesions in wild Rattus norvegicus and R. rattus. Lesions which included bilateral damage to the medial nucleus strongly reduced defensiveness but had no effect on flight behavior. In contrast, damage to nearby medial structures, which spared the medial nucleus, had no effect on defensiveness but reduced flight behavior. All lesions produced a transient decrease in activity but had no effect on startle reactions. The results suggest a differential organization of flight and defense behavior within the medial amygdala.