Brain Has a Strategy for Retrieving Memories, Research Shows
2005-12-22 16:33 (New York)


By Theresa Barry
     Dec. 22 (Bloomberg) -- When a person summons a memory, the
brain activates a pattern that retrieves general information
first, and then produces a more precise picture, a study says.
     Knowing this pattern may help future research into new
treatments for memory loss, said lead researcher Sean Polyn in a
telephone interview yesterday. The study appears tomorrow in the
journal Science.
     The researchers used functional magnetic resonance imaging
to watch ``people's thoughts unfold'' from memorization to
recall. They found that the brain will hunt down a specific
memory by starting with the general context, such as faces, and
then sort within that context to find a certain face.
     ``Everyone is afraid of losing their memory,'' said Polyn,
now a postdoctoral researcher in the Department of Psychology at
the University of Pennsylvania in Philadelphia. ``My hope is
that in the long run, the research will help us understand the
mechanisms underlying memory and guide treatment'' of diseases
that affect memory.
     The study's subjects were asked to memorize photos in three
categories: famous faces, well-known places and common objects.
In each case, the brain pattern seen when a subject first
memorized images from a category was similar to the pattern seen
when they were asked to recall a particular face. Unlike papers
in a filing cabinet system, memories are connected, Polyn said.
     The study, conducted in the lab of Professor Ken Norman at
Princeton University, was financed by the U.S. National
Institute of Mental Health.
     The nine students studied three lists, each OF WHICH had 30
photographs of places, objects and celebrity faces. All the
photographs were identified with a written label.

                          Brain Activity

     The researchers used functional MRIs, which records brain
activity over time, to determine where blood flow increased in
the brain when a person was asked to memorize or remember
something. The more active a certain part of the brain is, the
more blood it gets.
     ``We're interested in what happens in the brain while
people are searching their memories,'' Polyn said.
     The participants recovered general information about images
they were asked to memorize about 5 seconds or more before they
said they recalled the particular photographs, the researchers
said. A possible target for future research would be to
specifically define the memory being recalled, Polyn said.
     ``One of the exciting possibilities would be to show
specific memories coming to the surface -- if we could show that
a face pattern is a Jack Nicholson pattern and show Jack
Nicholson coming to the surface,'' he said.

--Editor: Gale.

Story illustration: For more information on the uses, benefits
and risks of functional MRIs, go to
http://www.radiologyinfo.org/content/functional_mr.htm.  For
more Bloomberg science stories, click on {NI SCIENCE <GO>}.

To contact the reporter on this story:
Theresa Barry in Washington at (1) (202) 624-1901 or
Tbarry2@bloomberg.net.

To contact the editor responsible for this story:
Glenn Holdcraft at (1) (212) 617-8968 or
gholdcraft@bloomberg.net.

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