Conditioned Taste and Place Preferences Induced by Electrical Stimulation of the External Lateral Parabrachial Nucleus: A General Reinforcing Mechanism?

Abstract

This study examined the stimulus specificity of external lateral parabrachial (LPBe) rewarding stimulation by using two identical learning procedures that may dissociate conditioned reinforcement to either the place or the flavor stimulus. Animals were presented with two distinct flavors in two different positions (left and right) that were varied throughout the experimental sessions. In the first experiment, LPBe stimulation was associated with one or other flavor, while in the second it was conditioned to one or other place in which these flavors were offered. The results show that, despite stimulus interferences, the animals develop specific conditioned preferences for the flavor stimuli (experiment 2A), and also for the place of their presentation (experiment 2B). These data are discussed in the context of brain reward systems and the biological constraints that characterize some learning modalities.