Decreased amygdala activation during risk taking in non-dependent habitual alcohol users: A preliminary fMRI study of the stop signal task.

BACKGROUND AND OBJECTIVES: Habitual alcohol use is prodromal to alcohol dependence. It has been suggested that impairment in impulse control contributes to habitual drinking. Little is known whether neural processes associated with impulse control is altered in non-dependent social drinkers. The current preliminary study combined functional magnetic resonance imaging and the stop signal task (SST) to address this issue.
METHODS: We compared non-dependent non/light (n = 12) and moderate/heavy (n = 9) young adult alcohol drinkers in a SST, in which they were required to exercise inhibitory control during the stop trials and were engaged in a speed/accuracy trade-off during trial-to-trial go responses. Our previous studies identified neural correlates of inhibitory control and risk taking during the SST ( [10] , [11] ). Furthermore, alcohol dependent patients showed altered brain activation both during inhibitory control and risk taking, compared to healthy controls ( [12] ).
RESULTS: We showed that moderate/heavy alcohol drinkers were decreased in amygdala activation during risk taking, while indistinguishable in neural measures of inhibitory control, when compared to non/light drinkers. CONCLUSIONS AND SIGNIFICANCE: Altered amygdala activation during risk taking may be a key neural process underlying early habitual alcohol use and a potential marker mediating transition to alcohol dependence.