Being born and raised in a major urban area is associated with greater lifetime risk for anxiety and mood disorders. Until now, the biology for these associations had not been described.  Jens Pruessner, from McGill University’s Douglas Mental Health University Institute (Canada), and colleagues looked at the brain activity of healthy volunteers from urban and rural areas. In a series of functional magnetic resonance assessments, the team showed that city living was associated with greater stress responses in the amygdala, an area of the brain involved with emotional regulation and mood. In contrast, urban upbringing was found to be associated with activity in the cingulate cortex, a region involved in regulation of negative affect and stress.  The team writes that: “ Our results identify distinct neural mechanisms for an established environmental risk factor, link the urban environment for the first time to social stress processing, suggest that brain regions differ in vulnerability to this risk factor across the lifespan,” and submit that their findings: “indicate that experimental interrogation of epidemiological associations is a promising strategy in social neuroscience.”