The role of left insula mediating impaired error processing in response inhibition in adult heavy drinkers

Identification of neurobiological mechanisms underlying development of alcohol use disorder is critical to ensuring the appropriate early-phase treatment and prevention of the disorder. To this aim, we tried to elucidate the disturbance of neural functions in heavy drinking, which can lead to alcohol use disorder. Because response inhibition is affected by alcohol use disorder, we examined neural activation and task performance for response inhibition using the Go/No-Go task in an fMRI paradigm in adult non-dependent heavy and light drinkers. We examined the neural activation for error processing and inhibitory control, components of response inhibition. We then investigated the mediating effect of the relevant neural substrate on the relationship between the level of alcohol drinking and task performance using mediation analysis. We found that heavy drinking significantly decreased activation in the left insula during error processing and increased the mean commission error rate for No-Go trials compared with light drinking. Mediation analysis demonstrated full mediation of the left insula activation during error processing for the relationship between drinking level and commission error rate. Our results suggested that left insula activation may be a neural marker pivotal for potential conversion to alcohol use disorder in individuals with high clinical risk such as heavy drinking.