Figure 2.

Effects of ER gene disruption on aggressive behaviors tested in two different paradigms, resident–intruder tests (A and B) and homogeneous set tests (C and D). Cumulative durations of aggressive bouts with (B and D) and without (A and C) offensive attacks are shown separately with different scales. ERKO mice showed very few aggressive behaviors even without attacks in resident–intruder tests (A; ∗, significantly different from WT mice at α = 0.05), whereas in the homogeneous set tests there were no differences between three genotypes (C). On the other hand, in both tests, cumulative duration of offensive attacks (B and D) were greatly reduced in ERKO mice compared with both WT and HZ mice (∗∗, α = 0.05).