Girls gone wild: Social isolation induces hyperactivity and exploration in aged female mice

The likelihood of experiencing social isolation increases later in life, particularly for females. It remains unknown how late-life social isolation impacts cognition and affective behavior in aged mice. We assessed the impact of late-life social isolation in 18-month old female mice. One month of single-housing did not lead to robust depressive-like symptomology, altered social interaction behavior, or sensitivity to context fear acquisition or memory. Rather, isolation increased hyperactivity and exploration, and reduced anxiety-like behavior in the open field and elevated plus maze, findings that have been similarly observed in young female and male mice following early-life isolation. These findings suggest that hyperactivity is a robust behavior following social isolation across the lifespan.