Conditioned flavor preference and aversion: role of the lateral hypothalamus.

Food-restricted rats with ibotenic acid lesions of the lateral hypothalamus (LH) and sham controls were trained to associate flavored solutions with positive or negative postingestive consequences. The LH rats learned to prefer a flavor that was paired with concurrent intragastric infusions of maltodextrin. Unlike controls, the LH rats failed to learn a preference for a flavor paired with delayed maltodextrin infusions and showed an attenuated preference for a flavor paired with concurrent fat infusions. The LH rats did not differ from controls in learning to avoid flavors paired with concurrent or delayed infusions of lithium chloride. These data indicate that the LH is not essential for all types of flavor-postingestive consequence conditioning but is critical for learning to associate flavors with delayed nutrient feedback.