Effects of Alcohol Exposure on Recognition Memory and Marble-Burying Tasks in Male and Female Aged Mice

Alcohol consumption in aging humans is a risk factor for cognitive impairment. This experiment assessed the effects of binge-like alcohol drinking in aged mice on memory (using the object recognition memory [ORM] task) and on anxiety-and compulsive-like behavior (using the marble-burying task). Subjects were 8 female and 10 male mice, 14–15 months old, selectively bred for low alcohol preference (LAP). Mice consumed either tap water or a 20% alcohol (v/v) solution in tap water through a drinking in the dark (DID) procedure for 4 consecutive days per week, for 3 consecutive weeks. One and 11 days after DID, mice completed marble-burying tasks to assess anxiety-and compulsive-like behavior after recent and delayed termination of binge-like alcohol drinking (Han et al., 2017). Twenty-four hours after the second marble-burying test, mice underwent an ORM task that assessed the recognition of a familiar over a novel object. LAP mice drank an average of 0.41 g/kg/hour and a total average of 13.13 g/kg over the course of the drinking period. Mice buried more marbles on the second test, but alcohol exposure did not affect marble burying. Alcohol females had significantly longer latency to explore the objects as compared to control females during initial exploration. This effect was not seen in LAP males, and there were no sex differences in other tests. Results indicate aged LAP mice exhibit diminished motivation for exploration, and alcohol consumption in LAP female mice may produce increased neophobia toward novel objects.