Take London. A city which is nearly ten times the size of Paris and which has, in what is defined as its center, a little more than 26,000 streets (against 5,064 public roads for the French capital). Then watch the drivers of its iconic black taxis – the black cabs – which, since 1865, have to pass a cycle of exams, known to say the least intimidating. – Knowledge – and often considered one of the most difficult in the world. A test that predates digital appendages like GPS and that technology has not yet sent back to oblivion of history.
Then choose, within this aristocracy, or better, this avant-garde of London taxis, a few holders of the green badge, the ultimate sign of recognition of the candidates who have overcome the pitfalls of this test which requires between three and four years of training. brainwashing and field training seven days a week, ten hours a day.
In practice, to explain, it is not simply a question of knowing how to get as fast as possible from Buckingham Palace to Tower Bridge. The suitor must first master on the fingertips a “Blue Book”, which lists 320 routes between different places in London, with, on the routes, all the buildings of interest and landmarks. He passes a written test, then the real marathon begins: with an oral, every two months, then every month, then every two weeks, during which the candidate will have to recite one by one the streets taken between two points of the megalopolis, on four different routes what is more. With the permanent risk, in the event of failure, of returning to square one.
So, sample a few of these phenomena, kings of asphalt in the London urban jungle. Then observe their phenomenal learning and memorizing abilities, scrutinize their brains as they deploy their encyclopedic knowledge of city space on the road, quantify their gray matter, examine neuron regeneration, if any, and try to learn lessons to fight against Alzheimer’s disease.
Within the laboratory of Hugo Spiers, a professor at University College London, several doctoral students in cognitive neuroscience are trying to unravel the mystery of the extraordinary skill in space developed by London taxis and use these findings to fight against Alzheimer’s disease, which can, with forms of atrophy in these parts of the brain, cause disorientation, in particular.
A more developed seahorse
Over the past two decades, two studies had already been published with the same subject and using the same very specific sample of the population: in 2000, the first, conducted by British and American researchers, concluded that the elite of drivers Londoners had a posterior hippocampus – the region of the brain that plays the most important role in learning and memorization – more developed than average; the second, in 2011, had confirmed the thesis that, in the brains of the cabbies – the nickname of black cab drivers –, the size of the hippocampus increased more and more with the duration of the driving activity over the years.
Since July, within the “Taxi Brains” project (“Taxi brains”), the team of researchers therefore studied, through real-time brain MRIs (magnetic resonance imaging), drivers as they plotted their routes in the London labyrinth. Professor Hugo Spiers detailed a few days ago in the American daily The Washington Post outstanding issues: “We don’t know much about how taxi drivers use their seahorses when choosing and planning routes. And how do they use other areas of the brain to solve the task of walking 26,000 streets? Can we explain why they can be quick to plan one route and take time to think of another? “
“I’m afraid of these forms of brain damage”
The goal for scientists is very concrete: “Understanding which parts of the hippocampus enlarge relative to navigation ability will provide essential information needed to help develop diagnoses for the earlier detection of Alzheimer’s disease,” adds Spiers. Early diagnosis will help doctors treat patients sooner, limiting disease and improving quality of life. “
For the taxi drivers who received the sum of 30 pounds sterling (35 euros) and a picture of their brains, the ransom of the study is really just fame. Not to say, but, obviously, that does not bother them. At the microphone of the BBC, one of the participants boasted at the beginning of the week: “I have a bigger seahorse than you. It is known among us. I have a very good memory, but it is not the same which is activated when one remembers one thing or the other. We react to localization signals, pick them up and interpret them all the time … I am doing this study because I am afraid of these forms of brain deterioration and, if I can help a little, it will be ae real joy. ”
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