Increased impulsivity in rats as a result of repeated cycles of alcohol intoxication and abstinence

Impulsivity is a risk factor for alcoholism, and long-term alcohol exposure may further impair impulse control in a manner that propels problematic alcohol use. The present study employed the rat 5-choice serial reaction time task (5-CSRTT) to measure behavioral inhibition and attentional capacity during abstinence from repeated 5-day cycles of alcohol liquid diet consumption. Task performance was not disrupted following the first cycle of alcohol exposure; however, evidence of impaired behavioral inhibition emerged following the third cycle of alcohol exposure. In comparison with controls, alcoholic rats exhibited deficits in inhibitory control during cognitively challenging 5-CSRTT tests employing variable intertrial interval (varITI). This behavioral disruption was not present during early abstinence (3 days) but was evident by 7 days of abstinence and persisted for at least 34 days. Interestingly, renewed alcohol consumption ameliorated these disruptions in impulse control, although deficient behavioral inhibition re-emerged during subsequent abstinence. Indices of increased impulsivity were no longer present in tests conducted after 49 days of abstinence. Alcohol-related impairments in impulse control were not evident in sessions employing highly familiar task parameters regardless of the abstinence period, and control experiments confirmed that performance deficits during the challenge sessions were unlikely to result from alcohol-related disruption in the adaptation to repeated varITI testing. Together, the current findings demonstrate that chronic intermittent alcohol consumption results in decreased behavioral inhibition in rats that is temporally similar to clinical observations of disrupted impulsive control in abstinent alcoholics performing tasks of behavioral inhibition. The present study employed the 5-Choice Serial Reaction Time Task (5-CSRTT) to evaluate the effects of prior chronic alcohol exposure on the impulsive-like behavior in rats. Alcohol-exposed rats exhibited deficits in inhibitory control and increased perseverative behavior during 5-CSRTT tests employing variable inter-trial intervals. These disruptions were not present during early abstinence (3d) but emerged by 7d abstinence and persisted for at least 34d. Renewed alcohol consumption ameliorated these disruptions, though deficient behavioral inhibition re-emerged during subsequent abstinence.