What and when to want? Amygdala-based focusing of incentive salience upon sugar and sex

Rationale Amygdala-related circuitry helps translate learned Pavlovian associations into appetitive and aversive motivation, especially upon subsequent encounters with cues. Objectives We asked whether mu-opioid stimulation via microinjections of the specific agonist D-Ala(2), N-MePhe(4), Gly-ol)-enkephalin (DAMGO) in central nucleus of amygdala (CeA), or the adjacent basolateral amygdala (BLA) would magnify sucrose or sex wanting, guided by available cues. Materials and methods CeA or BLA DAMGO enhancement of cue-triggered wanting was assessed using Pavlovian to instrumental transfer (PIT). Unconditioned food wanting was measured via intake, and male sexual wanting for an estrous female was measured in a sexual approach test. Sucrose hedonic taste liking was measured in a taste reactivity test. Results CeA (but not BLA) DAMGO increased the intensity of phasic peaks in instrumental sucrose seeking stimulated by Pavlovian cues over precue levels in PIT, while suppressing seeking at other moments. CeA DAMGO also enhanced food intake, as well as sexual approach and investigation of an estrous female by males. DAMGO wanting enhancements were localized to CeA, as indicated by Fos plume-based anatomical maps for DAMGO causation of behavioral effects. Despite increasing wanting, CeA DAMGO decreased the hedonic impact or liking for sucrose in a taste reactivity paradigm. Conclusions CeA mu-opioid stimulation specifically enhances incentive salience, which is dynamically guided to food or sex by available cues.