Trade.Information

Research persons: Jean-Claude Dreher

Location: Paris, France

Details

For the first time a French researcher, Jean-Claude Dreher of cognitive
neuroscience Center , in collaboration with a U.S. team of National Institute of
Mental Health (Bethesda, Maryland), just to show, among humans, how the activity
of a key chemical messenger, dopamine, affects vital neural circuits involved in
motivation, learning and so on.  so-called "reward circuits". They also
demonstrated how this activity changes during aging.  These results might
crucial in the long term, lead to therapeutic strategies for diseases linked to
abnormal brain aging, like Alzheimer's. They are published online in the
American journal the Proceedings of the National Academy of Science (PNAS).

To achieve these results, Jean-Claude Dreher and his colleagues observed the
brains of 20 young people aged twenty years and 13 sixty years old. To do this,
they have combined two powerful brain imaging techniques: the functional
magnetic resonance imaging (or fMRI), to see areas of the brain activated during
the task performance and emission tomography positrons (PET) to measure the
synthesis of dopamine. The neurobiologists have observed the brains of
participants while they watched the animated image of a slot machine, whether or
not an image showing a gain of money, these two images stimulating both the
neural circuits of reward .

Result?  Biologists have noticed that among the elderly, low production of
dopamine (observed in PET) is linked to abnormally high activation of a brain
area called prefrontal cortex (observed fMRI). Conclusion: This high activation
may reflect the existence of a compensation system we can have a neuronal
circuit of the award running a minimum when our old days, which is vital.
Another important fact: when participants learned that they had actually won the
slot machine, scientists have noted that two areas in the frontal and parietal
cortex were off less in the elderly than among young people. According to
Jean-Claude Dreher, this indicates that the brains of elderly is simply less
sensitive to rewards in this case here, money.

These data are very important for basic research and medical, only
circumstantial evidence - from clinical studies - suggested an association
between dopamine synthesis and the treatment of cerebral rewards . In addition,
there were no data in humans demonstrating the deterioration of this
relationship during aging.