http://www.mdlinx.com/neurology/top-medical-news/article/2016/07/20/4
Yale School of Medicine News
Why
some people handle stress better than others is a question that has
fascinated scientists for decades. Now a Yale–led team reports that
flexible brain activity in a particular area of the brain may predict
resilience. Conversely, its absence can help pinpoint those most at risk
for binge drinking, emotional eating, and angry outbursts, according to
a study published the week of July 18 in the journal Proceedings of the
National Academy of Sciences. Thirty research participants were given
fMRI scans while exposed to either highly threatening, violent, and
stressful images and to neutral, non–stressful images for six minutes
each. The scientists found three distinct patterns of response to
stress. The first pattern was characterized by sustained neural
activation of brain regions that signal, monitor, and process potential
threats. The second response pattern involved a dynamic pattern with
increased and then decreased activation, perhaps as the brain’s way of
reducing initial distress to a perceived threat. Finally, subjects
showed flexible neural responses in an area of the brain called the
ventral medial prefrontal cortex (VmPFC) during sustained stress
exposure. “Higher levels of neuroflexibility in this area of the brain
helped predict those who would regain emotional and behavioral control
during stress,” said Rajita Sinha, the Foundations Fund Professor of
Psychiatry, director of the Yale Stress Center and lead author of the
study. “The VmPFC seems to be the area of the brain which mobilizes to
regain control over our response to stress.” Prior studies have shown
consistently that repeated and chronic stress causes great damage to
neural structures, connections, and functions of the prefrontal cortex,
the seat of higher order cognition that helps regulate emotions, and
more primitive areas of the brain. In subsequent interviews with the
participants, the researchers found that those who did not show neural
flexibility in the VmPFC during stress were more prone to binge
drinking, episodes of emotional eating, and anger outbursts. Those
subjects might be at higher risk of alcohol abuse and addiction or
emotional dysfunction problems, which are hallmarks of exposure to
repeated and high levels of chronic stress, Sinha hypothesized.
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