Taxi drivers 'have brain sat-nav' (Thanks, Ben!)
The hippocampus was only active when the taxi drivers initially planned their route, or if they had to completely change their destination during the course of the journey.
The scientists saw activity in a different brain region when the drivers came across an unexpected situation - for example, a blocked-off junction.
Another part of the brain helped taxi drivers to track how close they were to the endpoint of their journey; like a metal detector, its activity increased when they were closer to their goal.
Changes also occurred in brain regions that are important in social behaviour.
Taxi driving is not just about navigation: "Drivers do obsess occasionally about what their customers are thinking," said Dr Spiers.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.