This image shows endogenous (red) and virally labelled (green) excitatory cells in the medial amygdala. Neural circuits involving the medial amygdala are responsible for attack and traumainduced aggression escalation. Synaptic transmission in these circuits are potentiated by attack and traumatic experience, and this synaptic potentiation drives aggression escalation. For more information, see the article by Nordman et al. (pages 4858–4880).