Browsing by Subject "High alcohol preferring"

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    Acute drug effects on habitual and non-habitual responding in crossed high alcohol preferring mice
    (Springer Nature, 2018-07) Houck, Christa A.; Grahame, Nicholas J.; Psychology, School of Science
    RATIONALE: Drug reward plays a central role in acquiring drug-seeking behavior. However, subjects may continue using drugs despite negative consequences because self-administration becomes habitual, and divorced from outcome values. Although a history of drug and alcohol use expedite habit acquisition, and in spite of the fact that self-administration leads to intoxication, the acute effects of drugs on habitual responding are not well understood. OBJECTIVES: We sought to observe how acute ethanol and amphetamine affect the balance between habitual and goal-directed behavior, as measured by a fluid-reinforced operant conditioning task. METHODS: Selectively bred crossed high-alcohol-preferring (cHAP) mice were trained on an operant conditioning task reinforced on a variable interval schedule with 1% banana solution, which was subsequently devalued via LiCl pairing in half the animals. Ethanol (1.0 g/kg), amphetamine (2.0 mg/kg), or saline was administered prior to a post-devaluation test. RESULTS: Overall, mice showed habitual behavior, but when divided into high- or low-responding groups based on training response rates, saline-treated, low-responding animals devalued, while saline-treated high-responding animals did not. Furthermore, amphetamine elicited devaluation even in high-responding animals, while ethanol prevented devaluation even in low-responding animals. CONCLUSIONS: These data show that ethanol shifts animals toward behaving habitually. This may illuminate why alcohol-intoxicated individuals display impaired judgment about the relative merits of drinking, and potentially serve as a mechanism by which intoxicated subjects resume previously devalued behaviors, such as comorbid drug use. These findings also show that high variable interval response rates facilitate a shift from goal-directed to habitual behavior.