The study also found that people who were raised in the city during their first 15 years of life were more likely to show increased activation in another brain region, a more global regulator of stress known as the anterior cingulate. In these individuals, the change appears to be more permanent than in people who move to cities later in life, says Jens Pruessner, director of aging and Alzheimer’s research at the Douglas Institute and one of the study’s co-authors, because it occurs during an important period of development. Living in the city during your early years “means you will become more alert to [stress] situations via the anterior cingulate for the rest of your life,” he says.