title: Cocaine can generate a stronger conditioned reinforcer than food despite being a weaker primary reinforcer.
abstract: The present study aimed to test the hypothesis that cues associated with drug-taking behavior become extra strong motivators of behavior compared with cues paired with non-drug reinforcers. In experiment 1, rats were trained to lever press for intravenous cocaine infusions and grain pellets. Each reinforcer was paired with a distinct audiovisual cue. When allowed to choose between these alternatives, rats chose grain on ~70-80 percent of trials. However, after extinguishing lever pressing, reintroduction of press-contingent cues during a test for cue-induced reinstatement generated more cocaine seeking than grain seeking (also observed on 3- and 8-week follow-up tests). To examine whether the same pattern of results would occur with two non-drug reinforcers, experiment 2 replicated experiment 1 using grain and sucrose as reinforcement alternatives. Rats chose sucrose over grain on ~70-80 percent of choice trials and also responded more for the sucrose cue than for the grain cue on the reinstatement test. The disconnect between primary and conditioned reinforcements in experiment 1 but not in experiment 2 suggests that drug cues may become exceptionally strong motivators of drug seeking. These results are consistent with cue-focused theories of addiction and may offer insight into the persistent cue-driven drug-seeking behavior observed in addiction.
authors.affiliation: Psychology Department, American University, Washington, DC, USA.
authors.forename: Brendan J
authors.initials: BJ
authors.lastname: Tunstall
authors.affiliation: Psychology Department, American University, Washington, DC, USA.
authors.forename: David N
authors.initials: DN
authors.lastname: Kearns
mesh_terms: D000818:Animals; D003042:Cocaine / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects*; D003463:Cues; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D058999:Drug-Seeking Behavior / Q000187:drug effects; D002523:Edible Grain; D005108:Extinction, Psychological / Q000187:drug effects; D005518:Food Preferences / Q000502:physiology; D007262:Infusions, Intravenous; D008297:Male; D051381:Rats; D020318:Rats, Long-Evans; D012054:Reinforcement, Psychology; D012646:Self Administration; D013395:Sucrose / Q000494:pharmacology; D013549:Sweetening Agents / Q000494:pharmacology
chemical_list: D018765:Dopamine Uptake Inhibitors; D013549:Sweetening Agents; D013395:Sucrose; D003042:Cocaine
keywords: Choice; cocaine; cue-induced reinstatement; food; rat; self-administration