Power
of the mind can stop you catching flu, researchers reveal
By Steve Connor, Science Editor
http://news.independent.co.uk/world/science_medical/story.jsp?story=439412
Scientists trying to find whether there is any truth to "mind
over matter" say brain activity can control resistance to influenza. They
have demonstrated a direct link between the brain's emotional state and the
body's immune defences to explain why depressed people are more likely to
catch a cold.
Although there is considerable research showing a person's mood can influence
their susceptibility to a virus, no previous study has found a direct link
to the brain.
Neuroscientists led by Richard Davidson, of the University of Wisconsin at
Madison, found electrical activity in the left prefrontal cortex - the region
of the brain above the left eye - appears to play a critical role in directing
the body's immune system.
High levels of activity in the same region of the brain are known to be linked
with a more positive attitude to life, with severely depressed people having
a particularly subdued left prefrontal cortex relative to their right prefrontal
cortex.
Professor Davidson's findings are published in the Proceedings of the National
Academy of Sciences. They checked 52 volunteers with a brain scanner, measured
each person's electrical activity in the left and right pre-frontal cortex
before injecting them with a flu vaccine to see how well their immune systems
responded to a simulated viral attack.
Over the next six months, the scientists monitored the levels of flu-fighting
antibodies that appeared in the blood of each volunteer. They found those
with relatively high levels of activity in the right pre-frontal cortex produced
greater amounts of flu antibody.
"This study established that people with a pattern of brain activity that
has been associated with a positive affective style are also the ones to show
the best response to the flu vaccine," Professor Davidson said. "It begins
to suggest a mechanism [that means] subjects with a more positive emotional
disposition may be healthier."
Scientists have demonstrated there is a link between pyschological wellbeing
and physical health. Severe stress and depression also have a direct impact
on the immune system, affecting chemical messengers called cytokines, which
are needed to recover from an infection. Professor Davidson added: "Emotions
play an important role in modulating bodily systems that influence our health."
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