Individual differences in food cue responsivity are associated with acute and repeated cocaine-induced vocalizations, but not cue-induced vocalizations
- 216 Downloads
Individuals prone to attribute incentive salience to food-associated stimuli (“cues”) are also more sensitive to cues during drug seeking and drug taking. This may be due in part to a difference in sensitivity to the affective or other stimulus properties of the drug. In rats, these properties are associated with 50-kHz ultrasonic vocalizations (USVs), in that they are elicited during putative positive affective and motivational states, including in response to drugs of abuse.
We sought to determine whether individual differences in the tendency to attribute incentive salience to a food cue (as measured by approach) were associated with differences in cocaine-induced USVs. We also tested whether the food cue would elicit USVs and if this response was related to approach to the food cue.
In experiment 1, rats underwent Pavlovian conditioned approach (PavCA) training where they learned to associate a cue (an illuminated lever) with the delivery of a food pellet into a food cup. Subjects were categorized based on their approach to the cue (“sign-trackers”) or to the food cup (“goal-trackers”). Rats subsequently underwent nine testing days in which they were given saline or cocaine (10 mg/kg i.p) and placed into a locomotor chamber.
In experiment 2, rats were first tested in the locomotor chambers for one saline-treated day followed by one cocaine-treated day and then trained in PavCA. USVs were recorded from a subset of individuals during the last day of PavCA to determine if the food cue would elicit USVs.
Sign-trackers produced 5–24 times more cocaine-induced 50 kHz USVs compared to goal-trackers for all days of experiment 1, and this response sensitized with repeated cocaine, only in sign-trackers. Similarly in experiment 2, individuals that produced the most cocaine-induced USVs on a single exposure also showed the greatest tendency to sign-track during PavCA. Lastly, while sign-trackers produced more USVs during PavCA generally, the cue itself did not elicit additional USVs in sign- or goal-trackers.
These results indicate a robust and consistent relationship between approach to a food cue and cocaine-induced USV production. Thus, these USVs may index the neurobiological differences underlying the behavioral distinctions of sign- and goal-trackers.
KeywordsAutoshaping Cocaine Incentive salience Pavlovian conditioning Positive affect Self-report Sensitization Ultrasonic vocalizations
This work was supported by a grant from the National Institute on Drug Abuse (P50DA037844). The authors would like to thank Dr. Alexis Thompson, Dr. Matt Paul, and Christopher King for their comments on earlier versions of the manuscript.
- Berridge KC (2001) Reward learning: reinforcement, incentives, and expectations. In: Medin DL (ed) Psychology of learning and motivation: advances in research and theory. Academic Press Inc., New York, pp. 223–278Google Scholar
- Bindra D (1978) How adaptive behavior is produced: a perceptual-motivation alternative to response reinforcement. Behavioral Brain Research 1:41–91Google Scholar
- Boakes R (1977) Performance on learning to associate a stimulus with positive reinforcement. In: Davis H, Hurwitz H (eds) Operant-Pavlovian interactions. Lawrence Erlbaum Associates, Hillsdale, pp. 67–97Google Scholar
- Burgdorf J, Kroes RA, Moskal JR, Pfaus JG, Brudzynski SM, Panksepp J (2008) Ultrasonic vocalizations of rats (Rattus norvegicus) during mating, play, and aggression: behavioral concomitants, relationship to reward, and self-administration of playback. J Comp Psychol 122:357–367CrossRefPubMedGoogle Scholar
- Hearst E, Jenkins HM (1974) Sign tracking: the stimulus-reinforcer relation and directed action. Proceedings of the Psychonomic Society, Austin, TXGoogle Scholar
- Mahler SV, de Wit H (2010) Cue-reactors: individual differences in cue-induced craving after food or smoking abstinence. PLoS One 5. doi: 10.1371/journal.pone.0015475
- Mahler SV, Moorman DE, Feltenstein MW, Cox BM, Ogburn KB, Bachar M, McGonigal JT, Ghee SM, See RE (2013) A rodent “self-report” measure of methamphetamine craving? Rat ultrasonic vocalizations during methamphetamine self-administration, extinction, and reinstatement. Behavioral Brain Research 236:78–89CrossRefGoogle Scholar
- Pavlov IP (1927) Conditioned reflexes: an investigation of the physiological activity of the cerebral cortex. Oxford University Press, LondonGoogle Scholar
- Versaggi C, King C, Meyer P (2016) The tendency to sign-track predicts cue-induced reinforcement during nicotine self-administration, and is enhanced by nicotine but not ethanol. PsychopharmacologyGoogle Scholar