Digging behavior discrimination test to probe burrowing and exploratory digging in male and female mice.

Digging behavior is often used to test motor function and repetitive behaviors in mice. Different digging paradigms have been developed for behaviors related to anxiety and compulsion in mouse lines generated to recapitulate genetic mutations leading to psychiatric and neurological disorders. However, the interpretation of these tests has been confounded by the difficulty of determining the motivation behind digging in mice. Digging is a naturalistic mouse behavior that can be focused toward different goals, that is foraging for food, burrowing for shelter, burying objects, or even for recreation as has been shown for dogs, ferrets, and human children. However, the interpretation of results from current testing protocols assumes the motivation behind the behavior often concluding that increased digging is a repetitive or compulsive behavior. We asked whether providing a choice between different types of digging activities would increase sensitivity to assess digging motivation. Here, we present a test to distinguish between burrowing and exploratory digging in mice. We found that mice prefer burrowing when the option is available. When food restriction was used to promote a switch from burrowing to exploration, males readily switched from burrowing to digging outside, while females did not. In addition, when we tested a model of intellectual disability and autism spectrum disorder that had shown inconsistent results in the marble burying test, the Cc2d1a conditional knockout mouse, we found greatly reduced burrowing only in males. Our findings indicate that digging is a nuanced motivated behavior and suggest that male and female rodents may perform it differently.

University housing reinforces the negative relationship between interpersonal violence, psychological distress, and suicidality in undergraduates, particularly among gender diverse students.

OBJECTIVE: To compare academic and mental health outcomes across diverse gender identities in the context of interpersonal violence and campus housing. PARTICIPANTS: 45,549 students from 124 self-selected post-secondary institutions. METHODS: Various academic and health measures from the National College Health Assessment Spring 2017 dataset were analyzed for differences across five gender identities (cis women, cis men, transwomen, transmen, and genderqueer students), and two housing categories (university housing and non-university housing). RESULTS: When compared to cisgender peers, gender diverse students reported greater experiences of interpersonal violence and higher levels of negative academic and mental health outcomes. Living in university housing was associated with an increase in these disparities. CONCLUSIONS: University housing, which usually reinforces fixed gender binaries, is associated with worse outcomes for gender diverse students. These data can help higher education institutions better understand and address problems that disproportionately impact transgender and gender diverse students, who represent a growing demographic.

Sequential delay and probability discounting tasks in mice reveal anchoring effects partially attributable to decision noise.

Delay discounting and probability discounting decision making tasks in rodent models have high translational potential. However, it is unclear whether the discounted value of the large reward option is the main contributor to variability in animals' choices in either task, which may limit translation to humans. Male and female mice underwent sessions of delay and probability discounting in sequence to assess how choice behavior adapts over experience with each task. To control for "anchoring" (persistent choices based on the initial delay or probability), mice experienced "Worsening" schedules where the large reward was offered under initially favorable conditions that became less favorable during testing, followed by "Improving" schedules where the large reward was offered under initially unfavorable conditions that improved over a session. During delay discounting, both male and female mice showed elimination of anchoring effects over training. In probability discounting, both sexes of mice continued to show some anchoring even after months of training. One possibility is that "noisy", exploratory choices could contribute to these persistent anchoring effects, rather than constant fluctuations in value discounting. We fit choice behavior in individual animals using models that included both a value-based discounting parameter and a decision noise parameter that captured variability in choices deviating from value maximization. Changes in anchoring behavior over time were tracked by changes in both the value and decision noise parameters in delay discounting, but by the decision noise parameter in probability discounting. Exploratory decision making was also reflected in choice response times that tracked the degree of conflict caused by both uncertainty and temporal cost, but was not linked with differences in locomotor activity reflecting chamber exploration. Thus, variable discounting behavior in mice can result from changes in exploration of the decision options rather than changes in reward valuation.