The brain’s emotion-processing center—the amygdala—is one of several brain regions involved in social behavior. But the exact role that this almond-shaped structure plays in the so-called ‘social brain’ remains mysterious. Now, researchers at the Friedrich Miescher Institute for Biomedical Research (FMI) in Basel, Switzerland, have found that the activity of different populations of neurons in the amygdala reflects whether mice interact with their peers, or whether they focus on self-centered behaviors such as grooming. The findings, published in Nature, could help to understand how the activity pattern of groups of neurons sets an overall brain state, and how that influences behavior—including social interaction and other behaviors that are impaired in neuropsychiatric conditions such as autism and social anxiety.