Long-term risk preference and suboptimal decision making following adolescent alcohol use

Abstract

Individuals who abused alcohol at an early age show decisionmaking impairments. However, the question of whether maladaptive choice constitutes a predisposing factor to, or a consequence resulting from, alcohol exposure remains open. To examine whether a causal link exists between voluntary alcohol consumption during adolescence and adult decision making the present studies used a rodent model. High levels of voluntary alcohol intake were promoted by providing adolescent rats with access to alcohol in a palatable gel matrix under nondeprivation conditions. A probability-discounting instrumental response task offered a choice between large but uncertain rewards and small but certain rewards to assess risk-based choice in adulthood either 3 weeks or 3 months following alcohol exposure. While control animals' performance on this task closely conformed to a predictive model of risk-neutral value matching, rats that consumed high levels of alcohol during adolescence violated this model, demonstrating greater risk preference. Evidence of significant risk bias was still present when choice was assessed 3 months following discontinuation of alcohol access. These findings provide evidence that adolescent alcohol exposure may lead to altered decision making during adulthood and this model offers a promising approach to the investigation of the neurobiological underpinnings of this link.adolescence ͉ probability discounting A dolescent alcohol use is a serious public health problem and is associated with an increased risk for development of chronic alcohol use disorders in adulthood (1). Furthermore, an association between a history of alcohol abuse and deficits in decision making has been documented (2-5). However, the question of whether maladaptive choices constitute a predisposing factor to, or a consequence resulting from, alcohol use remains open. Animal models allow for direct testing of causality and for examination of potential neural substrates underlying an association between alcohol use and risky decision making.Developing rodent models of alcohol abuse has been challenged by the fact that most rat strains do not freely consume significant amounts of ethanol in solution. A method for overcoming the reluctance of nondeprived rats to drink high levels of ethanol in solution was developed by Rowland et al. (6). It utilizes a palatable gel matrix containing ethanol and when made available to rats it stimulates robust and reliable selfadministration, without the need for fluid or food deprivation or any training period. Intake of these alcohol ''Jello Shots'' resulted in significant elevations of blood alcohol concentrations (6) in the range of 5 to 45 mg % with a linear relationship to amount consumed (r ϭ 0.94). Furthermore, alterations in brain chemistry in association with this administration protocol have also been documented (7-8). Since this delivery method does not require training to promote intake, it is particularly appropriate for developmental studies, such as those focused on adolescence, since, in ro...

Consequences of Adolescent Ethanol Consumption on Risk Preference and Orbitofrontal Cortex Encoding of Reward

“…This is an important departure from prior iterations of this task (Cocker et al, 2012;Nasrallah et al, 2009), which have relied on a step-wise reduction in the probability of risky reward across sessions. Our version of the task reduces the potential role of impaired behavioral flexibility on task performance.…”

“…Still, it is alarming that even moderate levels of intake, when consumed chronically during adolescence, exerted significant effects on both behavior and neurophysiology. While the gelatin vehicle used here is becoming increasingly common (Clark et al, 2012;Nasrallah et al, 2009Nasrallah et al, , 2011Peris et al, 2006), it is still a relatively new consumption model. In our hands, animals consuming control gelatin ate considerably more gelatin than both the alcohol groups.…”

“…Here, following the adolescent period, alcohol was no longer given to rats, and we examined preferences for risky payoffs across a range of probabilities, while simultaneously recording OFC activity using in vivo electrophysiology. Previous studies have shown enhanced risk-preference associated with altered neural signaling following similar adolescent alcohol consumption (Clark et al, 2012;Nasrallah et al, 2009Nasrallah et al, , 2011. We therefore hypothesized that greater modulation of OFC activity in response to rewards under conditions of risk would be associated with enhanced preference for the risky choice option across levels of risk.…”

Neural Correlates of Impulsivity in Healthy Males and Females with Family Histories of Alcoholism

“…This impulsivity component may predispose towards alcohol use. Given the trend correlations between F4 and alcohol-onset age, an alternate explanation involving early alcohol exposure leading to increased choice impulsivity also warrants consideration (Nasrallah et al, 2009). …”

Adolescent Alcohol Exposure Amplifies the Incentive Value of Reward-Predictive Cues Through Potentiation of Phasic Dopamine Signaling

“…The gelatin was made available 24 h/day in addition to ad libitum water and chow, and the jars were replaced with fresh gelatin every day. Alcohol and control gelatin was prepared as previously described (Clark et al, 2012;Nasrallah et al, 2009). Upon completion of the 20-day alcohol and control exposure, jars were removed and the rats were monitored daily for withdrawal symptoms.…”