Effects of MMPIP injection on aggressive behavior and social investigation in wild-type male mice. Cumulative duration of aggressive behavior (a) and social behavior (b), as measured by the resident–intruder paradigm. Intra-posterior division of the bed nucleus of the stria terminalis (BNSTp) injections of MMPIP reduced aggression, whereas intra-medial amygdaloid (MeA) injections had no effect. Intra-lateral ventricle injections needed a higher dose of MMPIP to induce behavioral alterations, indicating that the effect of intra-BNSTp injection was not due to diffusion into the lateral ventricle. n=10 for the BNSTp, n=7 for the MeA, n=5 for the lateral ventricle; *P<0.05, **P<0.01. Error bars indicate SEM. See also Supplementary Table S1.