Understanding the anxiolytic effects of alcohol on the central extended amygdala in humans

Abstract

The anxiety-reducing properties of alcohol are thought to contribute to development of alcohol dependence, particularly among individuals with anxiety disorders. Remarkably little is known, however, about the neural circuitry underlying anxiolytic effects of alcohol in humans. In a sample of 72 healthy adults, we employed the novel MultiThreat Countdown (MTC) task to investigate the dose-dependent consequences of acute alcohol intoxication (BAL range: 0.061 - 0.145%) during anticipation of certain or uncertain threat, compared to placebo. Focal analyses of the central extended amygdala revealed significant activation during threat in the right, but not left, hemisphere for both the central nucleus [Ce] and bed nucleus of the stria terminalis [BST]. Increasing BALs were associated with decreasing activation in right BST and self-reported fear/anxiety levels during threat. This effect did not differ between certain and uncertain threat. These results build upon converging lines of evidence and suggest involvement of BST in alcohol-induced anxiolysis.