A study by German scientists has shown that the brains of urban and rural residents perceive stressful situations differently.
The inhabitants of megacities react to them much more painfully than the inhabitants of villages and small towns. Moreover, their neurophysiological response to stress is so strong that it can lead to destructive changes in the brain.
City and countryside are two different worlds. Instead of the noise of foliage - the roar of the highway, instead of grass and trees - a jungle of concrete skyscrapers, instead of a small and constant circle of friends - thousands of indifferent strangers that we see on the streets and in the subway.
There is no doubt that a person who grew up in a quiet backwater is strikingly different from a city dweller. True, in stating this, we mean rather habits, the pace of life and, possibly, some psychological characteristics. But recently German scientists have discovered that the differences are much deeper. Even the brain works differently in townspeople than in rural areas, they say.
The recorded differences do not speak in favor of urban life … Previously, scientists have already found out that people born and raised in the city have twice the risk of schizophrenia.
And although the mechanisms behind the appearance of this mental disorder are still poorly understood, in this case the numbers speak for themselves. Not surprisingly, urban dwellers were 21 percent more likely to develop anxiety disorders than rural dwellers, and nearly 40 percent more people with mood swings.
However, the results of recent studies have amazed even seasoned scientists. Researchers at the University of Heidelberg in Germany and McGill University in Canada have used functional magnetic resonance imaging (fMRI) techniques to study the stress response of people from different areas. The fMRI technology allows you to record how actively a particular area of the brain is working.
In this case, the task of scientists was to find out how the brain of the participants in the experiment reacts to a stressful situation. Fifty volunteers temporarily solved arithmetic examples, and the experimenters deliberately made the subjects feel anxious about how they would cope with the task.
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In addition to changes in brain activity, changes in heart rate, blood pressure and the release of specific "stress" hormones served as indicators of stress.
The participants in the experiment were divided into three groups: villagers, residents of small towns with a population of tens of thousands, and residents of large cities with a population of more than 100 thousand people. In response to stress, subjects from different groups showed surprising differences.
First, in urban dwellers, when anxious, there was an excessive activity of the amygdala. The amygdala, or amygdala (located one in each hemisphere of the brain, inside the temporal lobe), is part of the limbic system that is responsible for regulating the functions of internal organs, instinctive behavior, emotions, memory, sleep and wake cycles.
Dysfunction of the tonsils is believed to be the root cause of mental disorders such as autism, depression, post-traumatic shock and phobias. (By the way, in patients whose amygdala has been destroyed, there is a complete lack of fear.)
"This gland is a kind of danger sensor in the brain, and therefore it is associated with anxiety and depression," - explained a researcher at the University of Heidelberg, Professor Andreas Mayer-Lindenberg.
Volunteers from large cities showed hyperactivity and another part of the brain - the so-called cingulate gyrus. This structure (also part of the limbic system), according to Mayer-Lindenberg, "is responsible for the control of emotions and the response to avoid danger."
It turns out that the inhabitants of megalopolises, already subject to daily stress, react to it much more painfully than residents of villages and small towns. Moreover, if the conclusions of the scientists are correct, then the very neurophysiological reaction to a stressful situation in townspeople is so strong that it can lead to destructive changes in the brain and emotional disorders.
Surprised by these unambiguous results, the researchers conducted an additional series of experiments with other subjects, offering them both stressful and non-stressful tasks.
However, the results were confirmed: differences in the activity of the cingulate gyrus and the amygdala arose precisely in response to stress and depended on the subject's place of residence. No other factors - age, marital status, education or income level - influenced the identified indicators.
Another notable fact: normally, the amygdala and the cingulate gyrus, being parts of a single limbic system, have a neural connection. However, for those who grew up in the city (even if they later moved to the suburbs or the countryside), "communication" between them is weakened. Apparently, the formation of connections between these parts of the brain occurs in childhood.
Identifying the specific stressors in urban life is the next challenge for scientists, says Prof Mayer-Lindenberg. Moreover, the pace of urbanization is growing. Sociologists predict that by 2050 the number of urban residents will be 70 percent of the total population of the planet.
Having learned exactly which features of a big city cause stress and how our body reacts to them, scientists could advise on improving the planning of cities and making life easier for the inhabitants of the megacities of the future.
YANA FILIMONOVA
