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Cocaine Addiction Causes Brain to Struggle in Evaluating Rewarding Behaviors, Study Shows
A new study led by researchers from Mount Sinai and Rutgers University has used neuroimaging to show how cocaine addiction impairs the brain’s ability to process and respond to reward-related information by dysregulating the normal function of dopamine neurons. The effect makes it more difficult for individuals to change their addictive behaviors.
Findings from the study were published this week in the journal Neuron.
With previous research, mostly in animal models, suggesting that chronic cocaine use degrades the normal function of dopamine, researchers designed a new study to investigate whether people with chronic cocaine use disorder demonstrate differences in how their brains process and represent prediction “errors,” which are defined as discrepancies between what an individual expects as a reward and what they actually receive.
The researchers used a simple decision-making task to measure different reward responses in the ventral striatum, a region in study participants’ brains that receives dense dopaminergic inputs. The results showed that prediction error responses reflected “utility” prediction errors, which incorporate an individual’s subjective experience of reward as informed by their unique preferences for risk and uncertainty.
The study found that utility prediction error responses were significantly reduced in people with cocaine addiction, who were generally more risk tolerant. Higher risk tolerance was associated with cocaine use in early adolescence.
“In people with chronic cocaine addiction, we observed a striking reduction in the way their reward system—a set of connected regions along the brain’s dopamine pathways—responds to the outcomes of the person’s decisions,” study senior author Rita Z. Goldstein, PhD, Mount Sinai professor in neuroimaging of addiction at the Icahn School of Medicine at Mount Sinai, said in a news release.
“Instead of signaling clearly when an unexpected reward was received and broadcasting this information throughout the brain to inform future decisions, the signal was attenuated, making it harder to learn from experience and modify decision-making to obtain better outcomes.”
The findings could lead to novel, targeted interventions that are designed to restore the impacted teaching signals.
“Although this basic science study does not have any immediate implications for public health or treatment, researchers can build on these findings to explore new treatments and prevention strategies,” said lead author Anna Konova, a psychiatry professor who leads a research lab at the Rutgers University Behavioral Health Care and Brain Health Institutes. “Specifically, our findings suggest that interventions that aim to boost the impact of the outcomes of one’s decisions (the perception of received rewards) may be a valuable strategy to normalize prediction error signaling and learning from experience in addiction.”
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