Friday, November 18, 2005

No longer "timid as a mouse"

Gleb Shumyatsky of Rutgers University and colleagues from Columbia University, Harvard Medical School and Albert Einstein College of Medicine published a paper in this month's issue of Cell that describes the creation of "fearless" mice.

Stathmin is a protein involved in the formation of the structural support inside nerve cells that is primarily expressed in the amygdalae*, parts of the brain involved in decoding emotions and responding to external threats. Shumyatsky and colleagues created mice with a "knockout" in the stathmin gene. The mice lacking stathmin expression did not show any "innate fear" of open spaces or "learned fear" of an electrical shock that accompanied a tone. It wasn't a general learning or memory problem, however; mutant mice didn't have any problem with a memory test that involved finding a dry platform in a water maze.

In typical hyperbolic style, the regular news media is reporting that stathmin is a "fear gene", which is simply inaccurate. It's likely that interfering with any gene involved in the formation of the amygdalae would produce a similar result. Since the amygdalae are involved in processing emotions, disruption in their development could also affect the ability to feel certain emotions and recognize emotions in other people.

This research should help scientists understand how fear-associated memories form, and could lead to better treatments for anxiety disorders and post-traumatic stress disorder.

Nature News article
Biology News article
• A better overview than mine at Pharyngula
• Article at Scientific American "Can We Cure Fear?"

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*stathminis also expressed in the testes - the reports don't mention whether the knockout had any effect on fertility or testicular development.


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