Cab drivers have satnav in the back of their brains

The secret of how London cabbies find their way around has been discovered.

Scientists say the drivers' brains have developed a strong "internal satnav".

Researchers at the Wellcome Trust put dozens of cabbies in a brain scanner, asked them to play a computer game recreating London streets and then analysed their brain activity.

The scientists found the brain area known as the hippocampus was larger than average in cabbies.

"The hippocampus is crucial for navigationand we use it like a 'sat nav'," Dr Hugo Spiers of the Institute of Behavioural Neuroscience at UCL told the BA Festival of Science in Liverpool today. "London taxi drivers have powerful innate satnavs, strengthened by years of experience."

He identified three types of cell behind the satnav effect: place cells map our location, direction cells tell us which way we are facing and grid cells how far we have travelled.