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Wednesday, February 8, 2012

Neural Mechanisms of Risk Taking and Relationships with Hazardous Drinking



Impulsivity, particularly risk taking, is believed to play a significant role in alcohol use disorders (AUDs). While risk taking has been measured using questionnaires, recent performance-based tasks such as the Balloon Analog Risk Task (BART) have shown considerable promise in understanding risky decision-making processes in drinkers. While the number of studies using the BART has grown significantly over the past decade, the neural mechanisms that underlie risky choices on the BART have only begun to be explored. The current study was designed to assess both the neural mechanisms of risk taking on the BART and to explore relationships between risk taking and hazardous drinking.

Seventy-nine individuals with an AUD completed an fMRI compatible version of the BART that required pumping simulated air into risky or nonrisky balloons to earn points on each trial, and deciding when to terminate pumping to earn points accumulated. Hazardous drinking was assessed with the Alcohol Use Disorder Identification Test (AUDIT).

Comparison of risky and nonrisky decisions revealed differences in the dorsal anterior cingulate cortex (dACC), anterior insula, and striatum. Comparison of Cashout responses and Explosions revealed increased responses in lateral prefrontal cortex, insula, ACC, and middle temporal gyrus during Explosions and greater response in inferior parietal lobe and caudate during Cashouts. When examining relationships between hazardous drinking and neural measures of risk taking, we found significant negative relationships with insula, striatum, and dACC.

The current results suggest that risk taking is associated with increased response in the dACC and anterior insula, regions previously implicated in representing error likelihood and negative outcome magnitudes, respectively. In addition, hazardous drinking was associated with responses in the dACC, possibly suggesting a reduced ability to predict the likelihood of errors and to predict negative outcomes associated with risk taking.


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