Searching the internet may help middle-aged and older adults keep their memories sharp, US researchers say.

Researchers at the University of California Los Angeles studied people doing web searches while their brain activity was recorded with functional magnetic resonance imaging scans.

"What we saw was people who had internet experience used more of their brain during the search," said Dr Gary Small, a UCLA expert on ageing.

"This suggests that just searching on the internet may train the brain - that it may keep it active and healthy," said Small, whose research appears in the American Journal of Geriatric Psychiatry.

Many studies have found that challenging mental activities such as puzzles can help preserve brain function, but few have looked at what role the internet might play.

"This is the first time anyone has simulated an internet search task while scanning the brain," Small said.

His team studied 24 normal volunteers between the ages of 55 and 76. Half were experienced at searching the internet and the other half had no web experience. Otherwise, the groups were similar in age, gender and education.

Both groups were asked to do internet searches and book reading tasks while their brain activity was monitored.

"We found that in reading the book task, the visual cortex - the part of the brain that controls reading and language - was activated," Small said.

"In doing the internet search task, there was much greater activity, but only in the internet-savvy group."

He said it appears that people who are familiar with the internet can engage in a much deeper level of brain activity.

"There is something about internet searching where we can gauge it to a level that we find challenging," Small said.

In the ageing brain, atrophy and reduced cell activity can take a toll on cognitive function. Activities that keep the brain engaged can preserve brain health and thinking ability.

Small thinks learning to do internet searches may be one of those activities.

"It tells us we probably can teach an old brain new internet tricks," he said.

Reuters