Previous cocaine self-administration disrupts reward expectancy encoding in ventral striatum

Area of Science:

• Neuroscience
• Addiction Research
• Behavioral Science

Background:

• The nucleus accumbens core (NAc) is crucial for processing reward timing and value.
• Understanding how cocaine affects NAc neural activity related to reward expectancy is vital.

Purpose of the Study:

• To investigate the impact of prior cocaine self-administration on NAc neural correlates of reward expectancy.
• To determine if cocaine exposure alters decision-making and neural responses during a reward-based task.

Main Methods:

• Recorded single-neuron activity in the NAc of rats with a history of cocaine or sucrose self-administration.
• Used an odor-guided decision-making task with manipulated reward value (delay and size).

Main Results:

• Cocaine-exposed rats exhibited increased impulsivity, preferring immediate rewards.
• Fewer NAc neurons responded to cues and reward delivery in cocaine-exposed rats.
• Remaining responsive neurons showed reduced directional and value encoding; reward-related firing was diminished at longer delays.

Conclusions:

• Prior cocaine self-administration significantly alters reward-expectancy encoding in the NAc.
• These neural changes likely contribute to the impaired decision-making observed in chronic cocaine users.