Critical role of amygdala in flavor but not taste preference learning in rats.

The role of the amygdala (AMY) in learning to associate complex flavor (taste + odor cues) with the oral and post-oral properties of nutrients was examined. Rats with excitotoxic lesions of the basolateral AMY learned to prefer flavors paired with intragastric (IG) infusions of maltodextrin or corn oil (Experiment 1), although the preference was slightly attenuated. However, rats with large AMY lesions failed to develop a preference for flavors paired with IG infusions of the same nutrients (Experiments 2 and 4) but were able to learn a preference for a taste mixture paired with IG maltodextrin infusions (Experiment 3). The rats with large AMY lesions also did not acquire a preference for a flavor cue paired with the sweet taste of fructose (Experiment 5). Collectively, these data provide evidence that AMY is essential for flavor- but not taste-nutrient preference learning.