The tendency to sign-track predicts cue-induced reinstatement during nicotine self-administration, and is enhanced by nicotine but not ethanol.
Some individuals are particularly responsive to reward-associated stimuli ("cues"), including the effects of these cues on craving and relapse to drug-seeking behavior. In the cases of nicotine and alcohol, cues may acquire these abilities via the incentive-enhancing properties of the drug.



To determine the interaction between cue-responsivity and nicotine reinforcement, we studied the patterns of nicotine self-administration in rats categorized based on their tendency to approach a food-predictive cue ("sign-trackers") or a reward-delivery location ("goal-trackers"). In a second experiment, we determined whether nicotine and ethanol altered the incentive value of a food cue.



Rats were classified as sign- or goal-trackers during a Pavlovian conditioned approach paradigm. Rats then self-administered intravenous nicotine (0.03 mg/kg infusions) followed by extinction and cue-induced reinstatement tests. We also tested the effects of nicotine (0.4 mg/kg base s.c.) or ethanol (0.7 g/kg i.p.) on the approach to, and reinforcing efficacy of, a food cue.



Sign-trackers showed greater reinstatement in response to a nicotine cue. Further, nicotine enhanced sign-tracking but not goal-tracking to a food cue and also enhanced responding for the food cue during the conditioned reinforcement test. Conversely, ethanol reduced sign-tracking and increased goal-tracking, but had no effect on conditioned reinforcement.



Our studies demonstrate that the tendency to attribute incentive value to a food cue predicts enhanced cue-induced reinstatement. Additionally, the incentive value of food cues is differentially modulated by nicotine and ethanol, which may be related to the reinforcing effects of these drugs.
Behavioral Neuroscience Program, Department of Psychology, State University of New York at Buffalo, Park Hall B72, Buffalo, NY, 14260, USA.
Cassandra L
CL
Versaggi
Behavioral Neuroscience Program, Department of Psychology, State University of New York at Buffalo, Park Hall B72, Buffalo, NY, 14260, USA.
Christopher P
CP
King
Behavioral Neuroscience Program, Department of Psychology, State University of New York at Buffalo, Park Hall B72, Buffalo, NY, 14260, USA. pmeyer@buffalo.edu.
Paul J
PJ
Meyer
D000818:Animals; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D003214:Conditioning, Classical; D003463:Cues; D058999:Drug-Seeking Behavior / Q000187:drug effects*; D000431:Ethanol / Q000494:pharmacology*; D005502:Food; D008297:Male; D009042:Motivation; D009538:Nicotine / Q000008:administration & dosage* / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000008:administration & dosage* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012054:Reinforcement, Psychology; D012201:Reward; D012646:Self Administration
D002492:Central Nervous System Depressants; D018722:Nicotinic Agonists; D000431:Ethanol; D009538:Nicotine
Acetylcholine receptor; Alcoholism; Attention; Autoshaping; Behavioral pharmacology; Drinking; Drug addiction; Goal-tracking; Mesolimbic dopamine; Motivation; Pavlovian conditioned approach; Sign-tracking; Smoking