Reproductive experience shapes distinct behavioral profiles in female mice

초록

Reproduction is essential for the continuation of species, and the brain plays a central role in optimizing reproductive fitness through hormonal modulation of neuronal circuits. In rodents, pregnancy induces a wide range of behavioral adaptations, including reduced anxiety, increased feeding, altered thermoregulation, enhanced nesting, and sleep changes, all of which reshape daily routines and social interactions. In this study, we investigated how reproductive experience influences exploratory and social behavior in female mice by comparing virgin, male-exposed, and pregnant groups. Pregnant females exhibited significantly increased approach time and frequency toward novel objects compared to other groups, suggesting heightened object-oriented motivation during pregnancy. In contrast, in a three- chamber social interaction test, virgin females showed a preference for the familiar mouse, whereas both male-exposed and pregnant mice preferred to interact with a novel conspecific, indicating a shift in social preference following male exposure or pregnancy. Additionally, we utilized custom MATLAB-based tracking algorithms to quantify movement and measure distances during behavioral assays, enabling precise analysis of exploratory patterns across groups. These findings highlight distinct behavioral shifts driven by reproductive experience, with object-related behaviors prominently altered in pregnant mice and social behaviors differing notably in virgins, providing insights into how pregnancy and prior social exposure modulate female behavioral strategies.