A study of the use of areas of the brain during different activities found that it is markedly more active when carrying out an internet search than when reading a book.
The stimulation was concentrated in the frontal, temporal and cingulate areas, which control visual imagery, decision-making and memory.
The areas associated with abstract thinking and empathy showed virtually no increase in stimulation.
The study's authors say it shows how our brains could evolve over the long term with the increased use of technology.
But while the internet brings benefits for the brain, they warned against its overuse, which could come at the expense of other brain functions linked to human interaction.
Previous studies have warned that too much computer use could be responsible for increasing levels of Attention Deficit Hyperactivity Disorder (ADHD).
Dr Gary Small, director of the memory and ageing research centre at the University of California, Los Angeles, said: "Young people are growing up immersed in this technology and their brains are more malleable, more plastic and changing than with older brains," he said.
"The next generation, as (Charles) Darwin suggests, will adapt to this environment. Those who become really good at technology will have a survival advantage - they will have a higher level of economic success and their progeny will be better off."
The brains of 24 volunteers between the ages of 55 and 76 were scanned for the study.
Participants were told to perform web searches and read books while undergoing functional magnetic resonance imaging scans, which record the blood flow to areas of the brain during cognitive tasks.
The study found that those searching the web generated considerably more brain activity than those reading books.
"A simple, everyday task like searching the web appears to enhance brain circuitry in older adults, demonstrating that our brains are sensitive and can continue to learn as we grow older," Dr Small said.
"The study results are encouraging, that emerging computerized technologies may have physiological effects and potential benefits for middle-aged and older adults.
"Internet searching engages complicated brain activity, which may help exercise and improve brain function."
The findings are expanded in Dr Small's book, iBrain: Surviving the Technological Alteration of the Modern Mind, and are published in the American Journal of Geriatric Psychiatry.
However, not everyone agreed with the findings. Igor Aleksander, emeritus professor of neural systems engineering at Imperial College London, said: "It may be that by using the internet you stimulate different parts of the brain. However, it would be difficult to show this could not be achieved through other situations."Original here