Prefrontal cortex fails to learn from reward prediction errors in alcohol dependence

Area of Science:

• Neuroscience
• Addiction Research
• Cognitive Psychology

Background:

• Addiction is characterized by persistent substance use despite negative consequences.
• Impaired behavioral flexibility in adapting to changing reward values may underlie addiction.
• Adaptive decision-making relies on updating action values, mediated by reward prediction errors (PEs) in the striatum and communication with the prefrontal cortex.

Purpose of the Study:

• To investigate the neural mechanisms of maladaptive behavior in male alcohol-dependent patients.
• To examine the role of striatal reward prediction errors and frontostriatal connectivity in addiction.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed.
• A reinforcement learning task was administered to human male alcohol-dependent patients.

Main Results:

• Striatal reward prediction error (PE) expression was found to be intact in alcohol-dependent patients.
• Abnormal functional connectivity between the striatum and dorsolateral prefrontal cortex (dlPFC) predicted impaired learning and increased alcohol craving.
• These findings align with previous reports of dlPFC structural abnormalities in substance dependence.

Conclusions:

• Frontostriatal connectivity is crucial for adaptive updating of action values and behavioral regulation in addiction.
• Deficits in addiction extend beyond the striatum, highlighting the importance of frontostriatal circuits.
• Impaired communication between the striatum and dlPFC contributes to maladaptive behavior and craving in alcohol dependence.