Fig. 3

Social behavior in 5-HTT-deficient mice. a–e Social interaction test in a novel environment: a the number of contacts, b total duration of contacts (s), c total duration of active contacts (s), d mean duration per contact (s), and distance traveled (cm). f–i Three-chamber social approach test: f time spent in the chamber with an empty cage, the center chamber, and the chamber with a cage containing a stranger mouse (stranger 1). g Time spent around the empty cage and the cage with stranger 1. h Time spent in the chamber with the cage containing stranger 1, the center chamber, and the chamber with a cage containing a novel unfamiliar mouse (stranger 2). i Time spent around the cage containing stranger 1 and the cage containing stranger 2. j–m Home cage social interaction test: j mean number of particles calculated for each 1-h period over 7 days, k mean number of particles averaged over the last 3 days, l mean activity level (arbitrary unit, A.U.) for each 1-h period over 7 days, and m mean activity level (A.U.) averaged over the last 3 days. Values are means ± SEM. a–e, j–m Asterisks and daggers indicate statistically significant differences between groups (5-HTT−/− vs. 5-HTT+/+, *p < 0.05 and **p < 0.01; 5-HTT−/− vs. 5-HTT+/−, ^†p < 0.05 and ^††p < 0.01). f–i Asterisks represent statistical significance with paired t tests (**p < 0.01)