Wilhelm CJ, Mitchell SH. Rats bred for high alcohol drinking are more sensitive to delayed and probabilistic outcomes. Genes Brain Behav 7: 705-713

Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, USA.
Genes Brain and Behavior (Impact Factor: 3.66). 10/2008; 7(7):705-13. DOI: 10.1111/j.1601-183X.2008.00406.x
Source: PubMed


Alcoholics and heavy drinkers score higher on measures of impulsivity than nonalcoholics and light drinkers. This may be because of factors that predate drug exposure (e.g. genetics). This study examined the role of genetics by comparing impulsivity measures in ethanol-naive rats selectively bred based on their high [high alcohol drinking (HAD)] or low [low alcohol drinking (LAD)] consumption of ethanol. Replicates 1 and 2 of the HAD and LAD rats, developed by the University of Indiana Alcohol Research Center, completed two different discounting tasks. Delay discounting examines sensitivity to rewards that are delayed in time and is commonly used to assess 'choice' impulsivity. Probability discounting examines sensitivity to the uncertain delivery of rewards and has been used to assess risk taking and risk assessment. High alcohol drinking rats discounted delayed and probabilistic rewards more steeply than LAD rats. Discount rates associated with probabilistic and delayed rewards were weakly correlated, while bias was strongly correlated with discount rate in both delay and probability discounting. The results suggest that selective breeding for high alcohol consumption selects for animals that are more sensitive to delayed and probabilistic outcomes. Sensitivity to delayed or probabilistic outcomes may be predictive of future drinking in genetically predisposed individuals.

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    • "For this study, in addition to lesioning the dopaminergic neurons by progressive administration of MPTP, cognitive deficits are behaviorally analyzed by a cued response task that requires animals to learn a stimulus–action–outcome contingency as well as to acquire the ability to exhibit behavioral flexibility, depending on the stimulus present at a given time (Wilhelm and Mitchell, 2008). This study examines behavioral changes via simple executive function testing and their relationships to dopaminergic and glutamatergic protein expression in the dorsolateral (DL) striatum, nucleus accumbens (NAc), and medial prefrontal cortex (mPFC) in a progressive MPTP mouse model. "
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    • ", in a direction similar to that reported by Poulos et al . ; Beckwith & Czachowski , 2014 ; Oberlin & Grahame , 2009 ; Wilhelm & Mitchell , 2008 ) , some demonstrates no relation ( Beckwith & Czachowski ) , or the opposite relation ( Wilhelm , Reeves , Phillips , & Mitchell , 2007 ) between these variables . These inconsistencies diminish the utility of examining alcohol consumption in rodent models when attempting to under - stand the relation between experimental manipulation of impulsive choice and subse - quent drug self - administration . "
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    • "Evidence of a genetic association between impulsive choice and sensitivity to both sweet-taste and drug-induced reward (Mitchell, 2011; Carroll et al., 2013) provides further support for common neurobiological mechanisms underlying impulsive choice and reward sensitivity. For instance, animals genetically bred to be high alcohol preferring consume greater amounts of saccharin (Sinclair et al., 1992; Stewart et al., 1994) and display steeper delay discounting than do low alcohol preferring animals (Wilhelm and Mitchell, 2008; Oberlin and Grahame, 2009). This genetic link is further supported by human studies that report an association between family history of alcoholism and both sweet taste liking and impulsive choice. "
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