Pavlovian-to-instrumental transfer in cocaine seeking rats - PubMed (original) (raw)

Pavlovian-to-instrumental transfer in cocaine seeking rats

Kimberly H LeBlanc et al. Behav Neurosci. 2012 Oct.

Abstract

Drug-associated cues are believed to be important mediators of addiction and drug relapse. Although such cues may influence drug-seeking behavior through multiple routes, it is their putative incentive motivational properties-their ability to elicit "craving"-that interests many addiction researchers. The Pavlovian-to-instrumental transfer paradigm is commonly used to assay cue-evoked incentive motivation in situations involving natural rewards, but has not been widely applied to the study of drug self-administration. We used this paradigm to determine whether cues paired with intravenous cocaine could promote performance of an independently trained task in which rats self-administered cocaine by completing a chain of two different lever press actions, a procedure used to parse behavior into cocaine seeking (first action) and cocaine taking (second action). Rats showed significant transfer, increasing task performance during cocaine-paired cues. This effect was observed for both seeking and taking actions, although a trend toward greater cocaine taking was observed, a result that is consistent with studies using natural rewards. Our results demonstrate that cocaine-paired cues can provoke the pursuit of cocaine through a Pavlovian motivational process. This phenomenon may provide a useful new tool for modeling drug relapse, particularly as a method for targeting the response-invigorating effects of stimulus-drug learning.

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Figures

Figure 1

Acquisition of the seeking-taking chain, shown as average lever presses over the session for the last five sessions of training. Means + SEM. *** p < 0.001.

Figure 2

Results of the first Pavlovian-to-instrumental transfer test. Difference scores for each minute of the CS and the first minute of the post-CS period, displayed separately for action (seeking or taking) and group (extinction or rewarded). A–B, results for the rewarded group for the seeking lever (A) and taking lever (B). C–D, results for the extinction group for the seeking lever (C) and taking lever (D). Means + SEM.

Figure 3

Results of the second Pavlovian-to-instrumental transfer test. Difference scores for each minute of the CS and the first minute of the post-CS period, separately plotted for seeking (A) and taking (B) levers. Means + SEM.

Figure 4

Probability of transitioning from the seeking to the taking lever vs. transitioning from the taking to the seeking lever. Probabilities are calculated by dividing the total number of transitions in each 1-second bin by the total number of 1st action lever presses in the session. A transition was operationally defined as the first response on the 2nd action lever within 10 seconds after a response on the 1st action lever. Means + SEM.

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Pavlovian-to-instrumental transfer in cocaine seeking rats - PubMed (original) (raw)