(A) Brain regions with identified roles in aggressive behavior. Putative graded response and threshold regions highlighted. Shading of contralateral regions done for display purposes. (B) Hormone- and experience-driven circuit changes within the overlapping aggressive and social behavior networks. (C) Proposed relationship between circuit plasticity and neural encoding of attack likelihood. Some circuit changes are more likely to affect graded representation of attack likelihood whereas others are more likely to change the relationship between neural activity and putative attack threshold. Abbreviations: LS, lateral septum; MPOA, medial preoptic area; BNST, bed nucleus of the stria terminalis; AH, anterior hypothalamus; pSI, posterior substantia innominata; VMHvl, ventromedial hypothalamus, ventrolateral area; MeA, medial amygdala; PA, posterior amygdala; PMv, ventral premammillary area; PAG, periaqueductal gray.