fMRI connects city living with mental health

This is you brain on city living

I'm studying neuroimaging this week in my neurology course so clicked on a link that struck me in my Nature.com news feed. The authors of City living and urban upbringing affect neural social stress processing in humans conducted a study that showed functional magnetic resonance images (fMRI) to prove that stress affects the brains of city folk differently. This sort of stress leads to physical and mental health disorders. In their words: "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 indicate that experimental interrogation of epidemiological associations is a promising strategy in social neuroscience."

Areas of the brain that are involved here include the perigenual anterior cingulate cortex (pACC) and the amygdala. The pACC region is involved in experiencing emotions and regulating behavioral as well as reacting to psychosocial stress. It may be the neuroanatomical structure that perceives social standing and thereby contributes to our mental and physical health. The amygdala is a part of the limbic system, which has been called the brain's emotional center. The amygdala is famously associated with fear and anxiety. It is connected to pathways responsible for defensive behaviors and it is the part of the brain that is responsible for emotional processing. In the city, these areas are always on alert. There, people are continually subject to the Shakespearean "slings and arrows" from bossy people and bad bosses. Saber-tooth tigers (cars, alarms, airplanes, and other such menacing noises) jump at them from every direction.

While the authors don't point to the flip side -- the physical and mental health benefits of one's proximity to a natural environment -- I'll do it here. Richard Louv might agree. As one who has personally benefited from re-establishing a healthy relationship with nature, I think I am physically and mentally better for it. I feel some sort of calming sense in my brain and body every time I get lost in examining the details of nature or get my hands, fingernails, and nostrils full of rich, fragrant soil. I would be in the portion of the study group that grew up in a rural environment and now lives in an urban area (population over 100,000). The study group that grew up and currently lived in an urban environment was of greater interest to the authors of the Nature article.

The authors conclude, "Our data reveal neural effects of urban upbringing and habitation on social stress processing in humans. These findings contribute to our understanding of urban environmental risk for mental disorders and health in general. Further, they point to a new empirical approach for integrating social sciences, neurosciences and public policy to respond to the major health challenge of urbanization." Ah, the far-reaching implications of brain research empowered by new neuroimaging technology.