Rutgers University
BRUNSWICK/PISCATAWAY,
N.J. – Contrary to long-held popular belief, our brains may not only produce
new brain cells or neurons throughout life, but the newly generated neurons quickly
become involved in the formation of new memories Ð a fact that may have positive
implications for the recuperative powers of our own brains when damaged by stroke
or other disease or trauma.
In a study published today in the March 15
issue of the journal Nature, Rutgers psychology professor Tracey J. Shors and
Princeton psychology professor Elizabeth Gould found that newly generated neurons
in the hippocampus area of animal brains help form new memories.
Despite
what is generally believed, scientists in recent years have learned that the brains
of vertebrate animals, a category ranging from amphibians to humans, continue
to produce new neurons throughout life. What was not known was whether the newly
generated cells are actively involved in memory formation.
To find out,
Shors and Gould studied the thousands of neurons produced daily in the hippocampus
area of rat brains, an area that controls a form of memory known as trace conditioning,
in which the animal must learn to associate stimuli that are separated in time.
The researchers discovered that when they reduced the production of new hippocampus
cells via a drug inhibitor, the rats were no longer able to form certain types
of new memories.
This occurred even though mature hippocampus neurons
remained functionally intact. On the other hand, when the researchers stopped
administering the drug inhibitor, thus restoring the hippocampus area's ability
to generate new cells, the ability to acquire trace memories was also restored.
"It appears that the new neurons become involved in memory about a week
to two weeks after they are generated and they are involved in memories normally
handled by the hippocampus," says Shors.
The team also noted that the
reduction of new hippocampal cells had no apparent effect on memory that depends
on other parts of the brain.
Although the researchers studied only the
hippocampus, their research implies that the brain's recuperative powers may be
far greater than previously thought. "We've known for some time that the brain
generates new cells throughout life," says Shors. "These results suggest that
one of the functions of these new cells is related to the process of memory formation."
In an earlier study, the two researchers demonstrated the nostrum, "use
it or lose it." In the earlier study of rat brains, they found that while most
new brain cells die within weeks of their generation, putting them to work through
hippocampal-related learning improved their survival rate.
Contact:
Kevin P. Hyland
732/932-7084, extension 633
E-mail: khyland@ur.rutgers.edu
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