video transcript

It's long been known that exercise is good for the brain. Now scientists know why. University of Queensland researchers have demonstrated that, in mice, there are molecular pathways that affect the brain's ability to regenerate. Professor Perry Bartlett says it presents evidence that a cure for dementia might be possible. (SOUNDBITE) PROFESSOR PERRY BARTLETT - DIRECTOR, QUEENSLAND BRAIN INSTITUTE, SAYING: "If we're right, we think we can not only stop, but perhaps reverse some of the cognitive decline." Neuroscientist Jana Vukovic placed mice on a rotating turntable, a section of which carried a small electrical charge. The mice were challenged to remember where it was. (SOUNDBITE) DR JANA VUKOVIC - NEUROSCIENTIST, QUEENSLAND BRAIN INSTITUTE, SAYING: "It doesn't take them very long to figure out that there is a zone that they should avoid." But for older mice, it was much more difficult...until after they'd run on an exercise wheel. The exercised mice developed higher levels of a protein in their brains called fractalkine. (SOUNDBITE) PROFESSOR PERRY BARTLETT - DIRECTOR, QUEENSLAND BRAIN INSTITUTE, SAYING: "It does point to fractalkine being the major regulator of this process." Fractalkine stimulates the production of new nerve cells, which enable learning. With age, the development of those cells slows, reducing the brain's abiliy to form new memories. (SOUNDBITE) PROFESSOR PERRY BARTLETT - DIRECTOR, QUEENSLAND BRAIN INSTITUTE, SAYING: "It turns out these cells, in fact, either stimulate or inhibit the production of these new nerve cells." The discovery could leasd to the development of fractalkine supplements for older people to stave off dementia, although the scientists say that anyone can produce their own fractalkine, simply by excercising. Rob Muir, Reuters