London, The human brain possesses a unique navigation system, much like satellite navigation, with in-built maps, grids and compasses, according to neuroscientist Hugo Spiers.

This mechanism resides in the brain's hippocampus area, which is responsible for learning and memory, famously shown to be different in a London taxi drivers' study carried out by Eleanor Maguire at University College, London.

The study showed that a region of the hippocampus was enlarged in London taxi drivers compared to the general population.

"London taxi drivers, who have to know their way around hundreds of thousands of winding streets, have the most refined and powerful innate sat-navs, strengthened over years of experience," informed Spiers, as he made a presentation at the BA Festival of Science.

Even bus drivers do not have the same enlarged area, suggesting that the difference is linked to 'knowledge' of the city's 250,000 streets built up by taxi drivers over many years.

In a follow-up study, Spiers and Maguire used the Playstation2 video game "The Getaway" to examine how taxi drivers use their hippocampus and other brain areas when they navigate.

Taxi drivers used the virtual reality simulation to navigate the streets of London whilst lying in an fMRI brain scanner. The researchers found that the hippocampus is most active when the drivers first think about their route and plan ahead.

In contrast, activity in a diverse network of other brain areas increases as they encounter road blocks, spot expected landmarks, look at the view and worry about the thoughts of their customers and other drivers.

"The hippocampus is crucial for navigation and we use it like a 'sat-nav'," said Spiers. Inside the hippocampus and neighbouring brain areas scientists have identified three types of cells which, said Spiers, make up the sat-nav. These are called place cells, head direction cells and grid cells.

"Place cells map out our location, lighting up to say 'you are here' when we pass a specific place. There are thought to be hundreds of thousands of place cells in the brain, each preferring a slightly different geographical place," Spiers said.

"Head direction cells act like a compass, telling us which way we are facing.

"Grid cells, discovered in 2005 by Edvard Moser's group at the Norwegian University of Science and Technology, tell us how far we have travelled using a grid-like pattern akin to how we use latitude and longitude for navigation."

EMAIL THIS NEWS COMMENTS No comments yet