November 17, 2005

Scientists find gene for fear in the brain

WASHINGTON (Reuters) - Scientists may have found a gene for
fear -- a gene that controls production of a protein in the
region of the brain linked with fearful responses.

Their finding, published on Thursday, could lead to new
treatments for mental disorders such as post-traumatic stress
disorder and generalized anxiety.

The gene, known as stathmin or oncoprotein 18, is highly
concentrated in the amygdala, a region of the brain associated
with fear and anxiety, the researchers report in Thursday's
issue of the journal Cell.

"This is a major advance in the field of learning and
memory that will allow for a better understanding of post-
traumatic stress disorder, phobias, borderline personality
disorder and other human anxiety diseases," said Gleb
Shumyatsky of Rutgers University in New Jersey, who worked on
the study.

"It will provide important information on how learned and
innate fear is experienced and processed, and may point the way
to apply new therapies."

Mice genetically engineered so they would not produce
stathmin had brain irregularities and were less able to
remember fear-conditioned responses, the researchers reported.

Learned fear develops after conditioning -- as when a
person is stung by a wasp and fears the insects afterward.
These memories are formed in the amygdala.

"This is the first time it has been shown that the protein
called stathmin -- the product of the stathmin gene -- is
linked to fear conditioning pathways," said Vadim Bolshakov,
director of the Cellular Neurobiology Laboratory at Harvard
University's McLean Hospital, who also worked on the study.

Also, the mice showed unusual behavior. Mice instinctively
avoid open spaces, but the stathmin-free mice showed no fear
and often explored more open areas than normal mice, the
researchers found.

So the gene may control both learned and innate fear, the
researchers said.

The mice might be useful for testing drugs and other
treatments of anxiety disorders, they said.