Extra Credit for Friday, July 8th: Mental well-being: A New York state: Urban brains behave differently from rural ones of mind:

Mental well-being
A New York state of mind
Urban brains behave differently from rural ones
Jun 23rd 2011 | from the print edition

“HELL is a city much like London,” Percy Bysshe Shelley in 1819.

Building off of Dutch researchers' discovery that city dwellers have a 21% higher risk of developing anxiety disorders and a 39% higher risk of developing mood disorders, Andreas Meyer-Lindenberg of the University of Heidelberg and his colleges used a scanning technique, functional magnetic-resonance imaging (fMRI) to examine the brains of city dwellers and those who live in rural areas under stressful conditions. Dr. Meyer-Lindenberg conducted several experiments; in the first experiment, he had both urban and rural participants of the same general mental healths lay down with their heads in a scanner. The participants were monitored for indications of stress, like high blood pressure, as they took impossible math tests designed for failure while receiving negative feedback through headphones. The brains of the urbanites and country dwellers reacted to the stress very differently in the amygdalas, a pair of structures divided among the two cerebral hemispheres, located deep inside the brain, and responsible for assessing threats and generating fearful emotions, and the perigenual anterior cingulate cortex (pACC), that regulates the amygdalas. In the case of the amygdalas, those who lived in the countryside had the lowest levels of activity in their amygdalas, where as the city dwellers had the highest levels of activity in their amygdalas. Because of the pACC's role in regulating the amygdalas, changes of the pACC may alter the amygdalas, however, the activity and reactions of the pACC are not flexible like the activity of the amygdalas, but are determined during childhood. In other words, a more urban childhood results in a more active pACC, but the activity of the amygdalas reflects where one is currently dwelling. The fMRI measured these correlations between the amygdalas and the pACC. The fMRI reflected the expectations of Dr. Meyer-Lindenberg and his team. The activity of the pACC for the native urbanite showed to be out of kilter. Furthermore, it has been proven that schizophrenia is more common among urbanites than rural dwellers, and that the pACC-amygdala link is quite often out of kilter in schizophrenia; however, Dr. Meyer-Lindenberg is resistent in claiming that his test results show the cause of the out-of-kilter connection. In order to check their results, Dr. Meyer-Lindenberg and his team conducted several subsequent experiments and assigned participants additional stress-free tasks; the subsequent tests matched the results of the original test conducted, and the results of the stress-free tasks showed that the first test was most definitely of social stress, not mental exertion. Therefore, urban brains indeed behave differently than rural ones under stressful situations.

http://www.economist.com/node/18864354