You are lying down with your head in a noisy and tightfitting fMRI brain scanner, which is unnerving in itself. You agreed to take part in this experiment, and at first the psychologists in charge seemed nice.
They set you some rather confusing maths problems to solve against the clock, and you are doing your best, but they aren’t happy. “Can you please concentrate a little better?” they keep saying into your headphones. Or, “You are among the worst performing individuals to have been studied in this laboratory.” Helpful things like that. It is a relief when time runs out.
Few people would enjoy this experience, and indeed the volunteers who underwent it were monitored to make sure they had a stressful time. Their minor suffering, however, provided data for what became a major study, and a global news story. The researchers, led by Dr Andreas Meyer-Lindenberg of the Central Institute of Mental Health in Mannheim, Germany, were trying to find out more about how the brains of different people handle stress. They discovered that city dwellers’ brains, compared with people who live in the countryside, seem not to handle it so well.
To be specific, while Meyer-Lindenberg and his accomplices were stressing out their subjects, they were looking at two brain regions: the amygdalas and the perigenual anterior cingulate cortex (pACC). The amygdalas are known to be involved in assessing threats and generating fear, while the pACC in turn helps to regulate the amygdalas. In stressed citydwellers, the amygdalas appeared more active on the scanner; in people who lived in small towns, less so; in people who lived in the countryside, least of all.
And something even more intriguing was happening in the pACC. Here the important relationship was not with where the the subjects lived at the time, but where they grew up. Again, those with rural childhoods showed the least active pACCs, those with urban ones the most. In the urban group moreover, there seemed not to be the same smooth connection between the behaviour of the two brain regions that was observed in the others. An erratic link between the pACC and the amygdalas is often seen in those with schizophrenia too. And schizophrenic people are much more likely to live in cities.