Paradigm: Conditioned Place Preference
Citation: Prus AJ, James JR, Rosecrans JA. Conditioned Place Preference. In: Buccafusco JJ, editor. Methods of Behavior Analysis in Neuroscience. 2nd edition. Boca Raton (FL): CRC Press/Taylor & Francis; 2009. Chapter 4. Available from: https://www.ncbi.nlm.nih.gov/books/NBK5229/
What is it supposed to measure?
The conditioned place preference paradigm is a common preclinical model for studying the effects of drugs, both rewarding and aversive. It involves associating one environment with drug treatment and another with the absence of the drug (using the drug's vehicle). This model is used to investigate how drugs affect an animal's preference for different environments.
How does it work?
In a conditioned place preference (CPP) experiment, when animals spend significantly more time in the compartment associated with a drug, it indicates a CPP. Conversely, if they spend significantly more time in the compartment associated with a vehicle, it's considered a conditioned place aversion (CPA).
What does a rodent do within this paradigm (or what happens to the rodent)?
In this experiment, typically conducted with rats or mice, an animal is initially given a drug injection with potentially rewarding or aversive effects and is placed into one of the outer compartments for a few minutes. The next day, the animal is injected with the drug's inactive vehicle and placed in the opposite outer compartment. This drug and vehicle alternation continues for 2 or 3 days. Finally, a test session is carried out, where the animal is placed in the center compartment, and the gates to both outer compartments are opened. The researchers then record the amount of time the animal spends in each outer compartment during this session to assess the drug's effects on the animal's preference or aversion.
What equipment do you need to run it?
A common variation of this experimental design involves a three-compartment chamber. The outer compartments are designed with distinct features, such as different wall colors, types of bedding, or flooring styles. The central compartment lacks any specific features and is not associated with a drug. Gates between these compartments can be opened, allowing the animals to move freely between them.
What else would you need to know to use it?
When training a Conditioned Place Preference (CPP), researchers often use an unbiased approach. Initially, the animal is allowed access to both compartments of the apparatus. If the animal shows a significant preference for one compartment over the other during this initial phase, they are excluded from the conditioning phase of the study.
Think about this paradigm. What are your thoughts, if any, on the validity of this method?
I think that this method lacks face validity and predictive validity. The ability of CPP to predict drug effects in human clinical settings is an important aspect of its validity. While CPP can provide insights into drug-induced preference or aversion, it may not always predict the full spectrum of human drug responses or complex behavioral and physiological effects. However majority of addictive substances produce CPP and it is frequently used to screen substances for abuse liability.
What concerns, if any, would you have using it as a measure?
One concern i would have is that this method is that the interpretation of CPP results can be complex. For example, an animal's preference for a drug-associated environment may not necessarily reflect the drug's efficacy but could be influenced by other factors such as novelty, exploration, or context-specific learning. Also CPP typically measures preference or aversion within a specific context but may not capture the full spectrum of a drug's effects, including potential long-term consequences, addiction liability, or withdrawal effects.