By Malcolm Ritter, AP Science Writer
Friday, February 10, 2012
NEW
YORK (AP)—People learned better when a key part of their brains got
mild zaps of electricity, a finding that may someday help Alzheimer's
patients keep more of their memories.
In
a small but tantalizing study, participants played a video game in
which they learned the locations of stores in a virtual city. They
recalled the locations better if they learned them while receiving a
painless boost from tiny electrodes buried deep inside their brains.
In
the future, that strategy might help curb memory loss for people in the
early stages of Alzheimer's disease, suggested Dr. Itzhak Fried, a
neurosurgeon at the University of California, Los Angeles. But he
cautioned that the results were preliminary.
Using
implanted electrodes to treat brain disease is hardly new. Such
"deep-brain stimulation" has been used for about a decade for
Parkinson's disease and some other disorders. Researchers are also
testing it for depression.
Some 80,000 or more people worldwide have had stimulation units implanted, mostly for Parkinson's.
Fried
and colleagues reported the new work in Thursday's issue of the New
England Journal of Medicine. It was financed by the federal government
and the Dana Foundation.
"I
think it's a terrific paper," said Dr. Andres Lozano, a professor of
neurosurgery at the University of Toronto, who didn't participate in the
work but is studying the approach in Alzheimer's patients. The new work
shows stimulation can modify the workings of brain circuits that
control memory in people, he said.
But like Fried, he cautioned that the research was still in the early stages.
"Whether
it will translate into something useful, we do not know," he said,
noting that years of additional study would be needed.
"You
don't want to do brain surgery on people unless you have a pretty clear
idea you're going to make them better," Lozano said. Deep-brain
electrodes are implanted through holes drilled in the skull.
The
study participants were seven epilepsy patients who had the electrodes
implanted to help surgeons identify the source of their seizures. Fried
and colleagues took advantage of that to stimulate a part of the brain
that's key to learning. The patients could not feel the stimulation.
The
patients played the video game on a laptop at their beds. Using a
joystick, they took the role of taxi drivers in a small town consisting
of four blocks by four blocks. They searched for passengers and dropped
them off at any of six stores they were asked to find. The electrical
stimulation was turned on while they learned the locations of some
stores, but not others.
Testing
showed that the stimulation made a difference. When given a store to
find, the patients took a more direct route to it, and got there faster,
if they had learned its location during a time of stimulation. When
researchers looked at how much extra wandering they did beyond the
shortest possible path, they found that stimulation reduced this excess
by an average of 64 percent.
The
patients were tested only a few minutes after learning the store
locations, so it's not yet clear how long the effect can last, Fried
said. Researchers will also have to see if stimulation helps for other
kinds of knowledge, he said.
Memory Enhancement and Deep-Brain Stimulation of the Entorhinal Area
SOURCE: The Associated Press
