Scientists create Danger Mouse

I, Science 22 November 2005
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NOVEMBER: Mice are not normally renowned for their boldness. Geneticists, however, appear to have created a fearless mouse by knocking out a single gene.

Unlike puny lab rats, these super-mice are seemingly indifferent to electrical shocks and, in a slap in the face to Pavlov and his dogs, even ignored a tone associated with the shocks. Normal mice, when conditioned in this way, become frozen with fear upon hearing the tone. The mice also showed an unusual willingness to explore wide open spaces in a new environment, areas where normal mice would fear to tread.

Fear stems from a part of the brain called the amygdala. Researchers led by Gleb Shumyatsky of Rutgers University, New Jersey, knocked out a gene called stathmin which regulates the development of structural molecules in nerve cells. Stathmin is predominantly expressed in the amygdala, and without it, neurones do not form normal connections with one another and memory of fear is affected.

"Understanding the molecules that regulate fear would allow us to characterize the basic mechanisms of memory formation," said Shumyatsky.

Rumours that the mice are planning a daring revolt against their captors have not been confirmed.