['Impulsive behavior is associated with both alcohol use disorders and a family history of alcoholism (FHA). One operational definition of impulsive behavior is the stop-signal task (SST) which measures the time needed to stop a ballistic hand movement.', 'Employ functional magnetic resonance imaging (fMRI) to study right frontal responses to stop signals in heavy drinking subjects with and without FHA, and as a function of alcohol exposure.', 'Twenty-two family history-positive (FHP; age\u2009=\u200922.7 years, SD\u2009=\u20091.9) and 18 family history-negative (FHN; age\u2009=\u200923.7, SD\u2009=\u20091.8) subjects performed the SST in fMRI in two randomized visits: once during intravenous infusion of alcohol, clamped at a steady-state breath alcohol (BrAC) concentration of 60 mg/dL, and once during infusion of placebo saline. An independent reference group (n\u2009=\u200913, age\u2009=\u200923.7, SD\u2009=\u20091.8) was used to identify a priori right prefrontal regions activated by successful inhibition (Inh) trials, relative to "Go" trials that carried no need for inhibition [Inh\u2009>\u2009Go].', 'FHA interacted with alcohol exposure in right prefrontal cortex, where alcohol reduced [Inh\u2009>\u2009Go] activation in FHN subjects but not in FHP subjects. Within this right frontal cortical region, stop-signal reaction time also correlated negatively with [Inh\u2009>\u2009Go] activation, suggesting that the [Inh\u2009>\u2009Go] activity was related to inhibitory behavior.'] Does family history of alcoholism interact with alcohol to affect brain regions involved in behavioral inhibition?