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Updated: May 8, 2026
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A Conditioned Place Preference Protocol for Measuring Incubation of Craving in Rats
Published on: November 6, 2018
Incentive learning for morphine-associated stimuli during protracted abstinence increases conditioned drug preference
Rachel J Smith1, Gary Aston-Jones1
1Department of Neurosciences, Medical University of South Carolina, Charleston, SC, USA.
Summary
Addiction research shows that experiencing drug cues during abstinence strengthens drug-stimulus associations. This incentive learning, not withdrawal, drives increased drug preference over time.
Area of Science:
- Neuroscience
- Addiction Research
- Behavioral Pharmacology
Background:
- Previous studies indicated rats show increased preference for drug-associated stimuli after protracted abstinence.
- This heightened preference suggests a role for learning during abstinence, but the exact mechanisms were unclear.
Purpose of the Study:
- To investigate whether experiencing drug-stimulus pairings specifically during abstinence is critical for increased drug place preference.
- To determine the role of incentive learning in updating conditioned responses to drug-associated stimuli during abstinence.
Main Methods:
- Male Sprague Dawley rats underwent initial morphine place conditioning.
- Morphine dependence was induced, followed by forced abstinence.
- Place preference was tested during abstinence, with some rats re-conditioned for morphine preference while abstinent.
Main Results:
- No difference in place preference was observed between dependent and non-dependent rats during abstinence without re-conditioning.
- Morphine-pelleted rats re-conditioned during abstinence showed significantly increased place preference.
- Placebo-pelleted rats did not show enhanced preference after re-conditioning.
Conclusions:
- Incentive learning during protracted abstinence is critical for the development of increased morphine place preference.
- This indicates incentive learning updates Pavlovian-conditioned responses to drug-associated stimuli, not just instrumental responding.
- Enhanced drug preference reflects increased acquisition of drug-stimulus associations during abstinence, not negative affective states.
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