Sex-specific behavioral effects of chronic opposite-sex visual contact in mice

Social environments exert profound influences on behavior and mental states. However, the impact of indirect social stimuli-specifically the visual recognition of opposite-sex conspecifics housed in adjacent cages-on mouse behavior has not been thoroughly investigated. This study aimed to comprehensively examine the sex-dependent behavioral effects of chronic opposite-sex visual exposure.

Male and female C57BL/6N mice were housed for 21 days in transparent cages placed adjacent to either opposite-sex or same-sex conspecifics. Following this period, a comprehensive behavioral test battery was conducted, including assessments of body weight, nociceptive sensitivity, aggressive behavior, anxiety-like behavior, social interaction, spatial working memory, and depression-like behavior.

In male mice, opposite-sex exposure induced significant increases in body weight, heightened nociceptive sensitivity, enhanced aggression, and reduced depression-like behavior. In female mice, opposite-sex exposure resulted in increased aggression, reduced anxiety-like behavior in the open field test, and decreased alternation performance in the Y-maze. No significant differences were observed in social interaction measures in either sex.

Chronic opposite-sex visual exposure in mice induces distinct behavioral changes in males and females. These findings highlight a novel mechanism by which non-contact social stimuli modulate behavior in a sex-dependent manner and provide insights relevant to understanding the influence of opposite-sex recognition on human psychology and behavior. Furthermore, the results emphasize the necessity of considering opposite-sex exposure when designing housing conditions and behavioral experiments in laboratory settings.