(movie will open in a separate window)
Many Americans are still searching
for ways to escape the anxiety caused by September 11th.
But as this ScienCentral News video
reports, brain scientists are studying how we put painful memories behind us.
Weeding out painful memories
Researchers at the Max
Planck Institute of Psychiatry in Germany, together with colleagues from
Italy, were able to locate receptors in the brain that are critical in helping
us manage our fears.
They took two sets of mice—one group genetically engineered
to lack cannabinoid
receptors, and a group of regular mice (a "control" group)—and
first conditioned them to expect a shock whenever they heard a certain sound.
During the following days, the mice were repeatedly exposed to the sound. At
first, all mice were frightened by the sound. But as the days went on the control
mice quickly stopped being scared by the sound, while the genetically engineered
hardly forget it."
Cannabinoids are the chemicals that bind to the cannabinoid
receptors, and they include a neurotransmitter, anandamide,
that is found naturally in the brain, as well as tetrahydrocannabinol
(THC), the active component in marijuana. But as far as overcoming our fears
or aiding in aversive memory clearance, smoking marijuana is not likely to be
as effective since it affects our brains and bodies in many
However, scientist do hope that this research leads to drugs
that can help with stress disorders, anxiety and phobias, without
the other side effects of marijuana.
The researchers' next step will be to give mice cannabinoid
boosters, in order to see if they forget their fears faster. The German government
funds their work.