Zurich scientists discover a link between stress and the brain

Zurich researchers have discovered that a neurotransmitter called norepinephrine, produced in large amounts during stressful situations, reconfigures communications in the brain.

In times of intense stress, our brains only have a fraction of a second to react, explains the Swiss Federal Institute of Technology ETH Zurich in a press releaseexternal link. The brain focuses its attention on the most important environmental cues in order to make life or death decisions in fractions of a second, which means that effective communication must be quickly established between different areas of the brain.

Until now, we did not know how the brain guided these fast processes. Tests on humans suggest a major role for noradrenaline, but it is not possible to directly examine this theory in humans because the release of norepinephrine can not be manipulated selectively.

Tests on mice have now allowed researchers to prove for the first time that a release of norepinephrine was in itself sufficient to very quickly connect various regions of the brain.

According to ETH Zurich, scientists "have applied the latest genetic techniques to stimulate a small center of the mouse brain, the locus coeruleus, which provides the entire brain with norepinephrine". They performed real-time magnetic resonance imaging (MRI) examinations of the brain of anesthetized animals while triggering the release of norepinephrine from the locus coeruleus.

In what is described as "amazing results," the researchers found that selective release of norepinephrine re-wired patterns of connectivity between different regions of the brain in a manner similar to changes seen in humans subjected to acute stress.

"Our results show that modern imaging techniques on animal models can reveal correlations that allow us to understand the fundamental functions of the brain in humans," says Johannes Bohacek, researcher at ETH Zurich. The researchers hope to be able to use similar badyzes in humans to diagnose the pathological hyperactivity of the noradrenaline system, badociated with anxiety and panic disorders.

The full report was published in the journal Neuronexternal link.