Scientists have created super-intelligent mice by altering a single gene.

Not only did the change make the mice clever, but it also meant the they were less likely to feel anxiety or recall fear, researchers found.

They hope the discovery may help the search for treatments for disorders such as Alzheimer's, schizophrenia and post traumatic stress disorder (PTSD).

Researchers from Britain and Canada altered a single gene to block the phosphodiesterase-4B (PDE4B) enzyme.

Scientists have created super-intelligent mice by altering a single gene. Not only did the change make the mice clever, but it also meant the they were less likely to feel anxiety or recall fear, researchers found

This is found in many organs including the brain, and can make mice cleverer and at the same time less fearful.

'Our work using mice has identified phosphodiesterase-4B as a promising target for potential new treatments,' said Steve Clapcote, a lecturer in pharmacology at Leeds University, who led the study.

He said his team is now working on developing drugs that will specifically inhibit PDE4B.

The drugs will be tested first in animals to see whether any of them might be suitable to go forward into clinical trials in humans.

In the experiments, published on today in the journal Neuropsychopharmacology, the scientists ran a series of tests on the PDE4B-inhibited mice.

They found the GM mice tended to learn faster, remember events longer and solve complex problems better than normal mice.

Researchers hope the discovery may help the search for treatments for disorders such as Alzheimer's, schizophrenia and post traumatic stress disorder (PTSD)

The 'brainy' mice were better at recognising a mouse they had seen the previous day, the researchers said.

INTELLIGENT MICE CREATED WITH 'HALF-HUMAN' BRAINS Last year, mice injected with human brain cells grow to have 'half human brains' that make them smarter than other rodents, scientists have found. Researchers claim that giving mouse pups a type of immature human brain cell, known as glial cells, caused their brains to grow differently so they became more human-like. These human glial cells, which are the support cells of the brain providing it with structure and nutrients, multiplied and grew to replace a similar type of cell in the brains of the mice. While the mice still had their own neurons - the cells that transmit and store information in the brain - the support cells were almost entirely human, according to the researchers. Tests in these mice showed that they appeared to have better memories than those that did not have these hybrid brains. It is thought the human cells improved the efficiency of the mice brains. The results have raised the prospect that it may be possible to make animals smarter by injecting them with human brain cells. Advertisement

And they were quicker at learning the location of a hidden escape platform.

They were also less able to recall a fearful event after several days than ordinary mice, and as PDE4B is also found in humans, this could be of interest in the search for treatments for brain conditions as well as mental decline linked to aging.

The experiments also showed that PDE4B-inhibited mice suffered less anxiety, choosing to spend more time in open, brightly lit spaces than normal mice, which preferred dark, enclosed spaces.

And while mice are naturally scared of cats, the modified mice responded less fearfully to cat urine, suggesting that inhibiting PDE4B could increase risk-taking behavior.

Dr Laura Phipps of Alzheimer's Research UK, who were not involved in the study, said: 'This study highlights a potentially important role for the PDE4B gene in learning and memory in mice, but further studies will be needed to know whether the findings could have implications for Alzheimer's disease or other dementias.

'We'd need to see how this gene could influence memory and thinking in people to get a better idea of whether it could hold potential as a target to treat Alzheimer's.

'There is currently a lack of effective treatments for dementia and understanding the effect of genes can be a key early step on the road to developing new drugs.