Scientists have genetically modified mice to be super intelligent and found they are also less anxious, a discovery that may help in the search for treatments for disorders such as Alzheimer's, schizophrenia and post traumatic stress disorder (PTSD).

Researchers from Britain and Canada found that altering a single gene to block the phosphodiesterase-4B (PDE4B) enzyme, which is found in many organs including the brain, made 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 Britain's Leeds University, who led the study.