Extinction learning of stimulus reward contingencies: The acute effects of alcohol

Background: Recent theories suggest that extinction is, at least partly, new learning suppressing original associations between a conditioned stimulus and a conditioned response without severing those associations. During extinction alcohol via its effects on inhibitory control may reduce the ability to suppress the original associations between a conditioned stimulus and a conditioned response leading to an impairment of extinction learning. Thus, the present study is set out to examine the effects of alcohol on extinction learning to enhance current knowledge on mechanisms of extinction and conditions that might hamper extinction, which is an important aspect for the treatment of alcohol-dependent patients. Methods: Light to moderate social drinkers (N = 32) acquired an instrumental reward seeking response. Extinction training of the reward seeking response was performed after administration of a dose of 0.8 g/kg alcohol resulting in a peak blood alcohol concentration ranging from 112 to 184 mg/dL. In addition, we assessed subjective alcohol effects and administered a Stop-Signal task which measures the ability to inhibit a pre-potent motor response. Results: Alcohol influenced subjective ratings of light-headedness and increased the Stop-Signal reaction time indicating disinhibiting effects. However, our results did not show any impairment of learning of extinction after the administration of alcohol. Behavioural as well as attentional responses indicated extinction of conditioned responses for both experimental groups. Conclusions: These findings suggest that alcohol at a dose that impairs performance in a task of inhibitory control does not impair learning of extinction.