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Masked fears: Are fears that are seemingly overcome only hidden?

Masked fears: Are fears that are seemingly overcome only hidden?

One group of nerve cells in the brain controls the fear behaviour (right). This can be suppressed by a second group of nerve cells (left) — but the fear is only masked, and has not disappeared completely. (Credit: Carlos Toledo/Bernstein Center Freiburg)

From the March 18 2011 Science Daily News Item

ScienceDaily (Mar. 20, 2011) — Fear is a natural part of our emotional life and acts as a necessary protection mechanism. However, fears sometimes grow beyond proportions and become difficult to shed. Scientists from Freiburg, Basel and Bordeaux have used computer simulations to understand the processes within the brain during the formation and extinction of fears.

In the current issue of the scientific journal PLoS Computational Biology [full text of article], Ioannis Vlachos from the Bernstein Center Freiburg and colleagues propose for the first time an explanation for how fears that were seemingly overcome are in reality only hidden

The reason for the persistency of fears is that, literally, their roots run deep: Far below the cerebral cortex lies the “amygdala,” which plays a crucial role in fear processes. Fear is commonly investigated in mice by exposing them simultaneously to a neutral stimulus — a certain sound, for example — and an unpleasant one. This leads to the animals being frightened of the sound as well. Context plays an important role in this case: If the scaring sound is played repeatedly in a new context without anything bad happening, the mice shed their fear again. It returns immediately, however, if the sound is presented in the original, or even a completely novel context. Had the mice not unlearned to be frightened after all?

 

March 22, 2011 - Posted by | Medical and Health Research News | , , , ,

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