Gender differences in delay-discounting under mild food restriction

S. Koot, R. van den Bos, W. Adriani, G. Laviola

    Research output: Contribution to journalArticleAcademicpeer-review

    Abstract

    Abstract: Impulsivity, a core symptomof attention-deficit hyperactivity disorder (ADHD), is tested in animal models by delay-discounting tasks. So far, mainly male subjects have been used in this paradigm at severe levels of food restriction. Here we studied the impulsive behaviour of CD-1 adult male and female mice at mild levels of food restriction. Mice maintained at 90±5% of ad libitum bodyweight, were tested in operant chambers provided with nose-poking holes. Nose poking in one hole resulted in the immediate delivery of one food pellet (small-soon, SS), whereas nose poking in the other hole delivered five food pellets after a delay (large-late, LL), whichwas increased progressively each day (0–150 s). Two subgroups emerged: individuals that shifted at short delays (“steep”) and individuals that did not shift, even at the highest delays (“flat”). Analysis showed that “steep” females shifted at shorter delays than “steep” males, while no difference existed between males and females within the “flat” sub-population. In homecage circadian activity as well as in a novelty-seeking test, females were more active than males. It can be concluded from these results that female mice are more impulsive than male mice under mild food restriction. This is in contrast with findings in earlier studies with more severe food restriction. Therefore, an alternative explanation is that females are more explorative, and that different features might be tested in delay-discounting paradigms, depending on restriction levels
    Original languageUndefined/Unknown
    Pages (from-to)134-143
    Number of pages10
    JournalBehavioural Brain Research
    Volume200
    Publication statusPublished - 2009

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