Drug may heal injured brains

Ben Thompson says volunteers will be strictly vetted to make sure they are not at risk from Prozac. Photo / Martin Sykes

Many parents will have noticed the way a child's brain seems more ready to adapt than an adult's.

What they probably do not suspect is that the way to catch up could be a mild dose of anti-depressants.

Starting early next year, researchers at the University of Auckland will test whether mild doses of Prozac can make an adult's brain more open to healing and learning.

The research will use carefully vetted, healthy adults and is not intended to touch on depression.

The aim is to find out whether Prozac could help adults recover from strokes and brain injuries, and take advantage of therapies that were assumed to work only on children.

Fluoxetine (Prozac's scientific name) has been shown to add flexibility to the brains of adult mice.

Now Drs Ben Thompson and Cathy Stinear of Auckland University have won a $300,000 Marsden Fund research grant to see if it works on humans.

They will begin by testing its effectiveness at healing "lazy eye" - a common visual problem caused when one eye is weaker or points in a slightly different direction from the other.

Dr Thompson, of the university's department of optometry and vision science, said lazy eye was a good test case because the problem was usually fixed in the brain after a certain age - in fact it was considered untreatable once a child reached 7 years old.

When a person has amblyopia, or lazy eye, the brain adapts by favouring images from the good eye, often becoming so set in its ways that sight in the weaker eye does not return even after the underlying problem is fixed.

"The brain is not sufficiently plastic [able to change] to allow recovery of function in the lazy eye," said Dr Thompson.

He explained: "As we get older, our brains become progressively less able to change.

"During childhood, the brain is actually quite plastic and can adapt to a whole range of different problems ... and is very receptive to learning new skills.

"But as we get older, it seems our brains take on more of a fixed state."

Dr Thompson said the lack of flexibility made it much harder for adults to recover from brain damage or disorders where the brain had developed abnormally. He was hopeful Prozac would boost the rate of learning.

"It is a really good way of looking at whether fluoxetine drugs can boost plasticity. The theory would be that therapies that work in children but don't work in adults could work in adults if we can increase brain plasticity," he said.

Tests will begin on people with normal sight - 20 who will take a low-dose three-week course of Prozac and 20 who will get placebos - before testing recovery in people with lazy eyes.

Human guinea pigs will take eye-tests involving screens of moving dots designed to stretch their brains' visual abilities, while researchers monitor how quickly their scores improve.

Their brains will be monitored to see whether it is only the visual centre of the brain that is affected, or brain plasticity more generally.

Dr Thompson said volunteers would be strictly vetted to make sure they were not at risk from the drug.

Prozac has been linked to increased suicidal thoughts in severely depressed children and adolescents.

The Marsden Fund, from which researchers were awarded a record $66 million this year, is paid for by the Government in the Budget, and administered by the Royal Society of New Zealand.

In total, 111 projects were funded at various universities and crown research institutes, out of 934 applications.

MARSDEN FUND
* Government research fund.
* $66 million in the pot.
* 934 applications.
* 111 successful.
* 36 grants to researchers at the beginning of their careers.