Indiana University-Purdue University Indianapolis (IUPUI) / Habit expression is emerging as a theory of addiction: subjects begin to use drugs to attain positive reinforcing effects but continue to use in spite of negative effects because the behavior becomes habitual, and therefore divorced from its outcome. Many studies have shown that a history of drug and alcohol use lead to expedited acquisition of a habit, but the acute effects of these drugs on behavior is still unknown. Behaviors that result from acute intoxication, such as increased aggression, risky sexual behavior, and impaired judgment, could be interpreted as habitual: actions performed without regard for the outcome. Therefore, we studied the transition from goal-directed to habitual behavior, when a response is made regardless of outcome value, and how acute intoxication of ethanol (EtOH), amphetamine (AMP), nicotine (NIC), and yohimbine (YOH) affect the resulting behavior. Through a series of four experiments, selectively bred crossed High Alcohol Preferring (cHAP) mice were trained on an operant task to self-administer 1% banana solution, which was subsequently devalued via LiCl CTA. EtOH (1 & 1.5 g/kg), AMP (2.0 mg/kg), NIC (0.5 mg/kg), YOH (1.0 mg/kg), or SAL were administered prior to baseline and post-devaluation tests. We found that acute EtOH at 1- and 1.5-g/kg doses facilitated the expression of a habit, whereas all other pretreatments resulted in devaluation. These data may indicate a unique role for EtOH in facilitating the retrieval of habitual over outcome-based associations. This could shed light on why intoxicated individuals display impaired judgment and a mechanism by which relapse after a period of abstinence can occur.

<p dir="ltr">Alcohol is the most frequently used drug among adolescents and is commonly consumed through binge drinking. This pattern involves repeated rapid and heavy consumption of alcohol followed by abstinence. Continued binge drinking can result in increased susceptibility to drink during adulthood and a higher risk of adverse health issues, including cognitive impairment. The prefrontal cortex (PFC) and hippocampus (HIPP) are two of the main regions affected by binge drinking, which may lead to individuals experiencing impairment in cognitive processes such as sensorimotor gating and object recognition memory. However, the mechanisms underlying these processes can be complex. Extensive research needs to be conducted to examine the effects adolescent alcohol consumption can have on cognitive processing. A critical note is using an appropriate model to effectively study this relationship. The purpose of this work was to investigate the association between adolescent binge-like alcohol consumption, cognition-related behaviors, and neuroinflammatory responses in crossed high alcohol-preferring (cHAP) mice, a unique selectively bred mouse model for binge alcohol drinking and its consequences in humans.</p><p dir="ltr">Results showed alcohol history mice increased alcohol intake from adolescence to early adulthood, with females displaying faster escalation. Sensorimotor gating was impaired in the alcohol history group at the 112dB pulse intensity one week after alcohol consumption. Alcohol history male mice exhibited impairment in object recognition memory while females did not. IL-1β and TNF-α in the PFC and HIPP did not vary based on alcohol history or sex. These data provide information on the validity of cHAPs as a model of adolescent to early adulthood binge drinking. Our findings allow a foundation for future research to delineate the effect adolescent binge drinking has on various cognitive processes that are modulated by overlapping brain regions. This will aid in not only educating the public to facilitate more conscious actions but also provide potential therapeutic targets and interventions for those with alcohol use disorder (AUD).</p>