What London Cab Drivers Can Teach Us About the Alzheimer’s Brain

December 6, 2021

Taxi drivers in London have to complete one of the most difficult memorization tests in the world: a detailed exam called “the Knowledge” in which they must memorize some 26,000 streets in the city’s center and learn how to navigate from one location to another without the help of Google Maps or another GPS device. The test can take three to four years to study for and complete.

Now researchers in University College London are looking to the cab drivers to learn more about how their memory skills and training may help to bolster the brain against the ravages of a disease like Alzheimer’s.

“London cabbies have remarkable brains,” said Hugo Spiers, a professor of cognitive neuroscience who is leading the study with several graduate students. “Specifically, their brains’ are larger in a region that shrinks early in Alzheimer’s disease — the hippocampus.”

The study, called Taxi Brains, is enrolling 30 cab drivers who have successfully completed “the Knowledge.” Participants will receive about $40 to undergo MRI brain scan while completing several tests to assess their ability to plan routes through the streets of London. They will also play a video brain-game called Sea Hero Quest that tests their navigation skills while researchers scan their brains.

Earlier research has shown that the London taxi driver’s ability to reliably navigate various street routes and plan trips on the fly through traffic and varying road conditions changes their brains. A study from 2000 found, for example, that in the taxi drivers, the hippocampus, the part of their brain involved in spatial navigation, tends to be larger than that of their peers who don’t engage in these complex travel tasks. The longer they are on the job, the larger their hippocampus becomes.

The hippocampus, one of the first areas of the brain to be affected by Alzheimer’s, shrinks as the diseases progresses. That’s one reason why people with Alzheimer’s so easily become disoriented and get lost, a problem that becomes increasingly severe as the disease progresses.

 “Understanding which parts of the hippocampus get bigger in relation to navigation ability will provide critical insights needed to help develop diagnostics for the earlier detection of Alzheimer’s disease,” Dr. Spiers explains. “Early diagnosis will help doctors treat patients sooner, limiting the disease and improving quality of life.”

One theory is that complex brain games and memory challenges helps to build so-called cognitive reserve. According to this theory, such brain training helps to generate new brain cells inside the hippocampus, building up a so-called cognitive reserve. As diseases like Alzheimer’s cause brain cells to die off, enough healthy cells remain to keep thinking logical and clear and memory apparently intact.

The researchers hope to learn more about the ways in which bolstering the hippocampus through complex memory training might help to protect the brain against Alzheimer’s. Other studies have suggested the cognitively stimulating jobs or tasks, like completing crossword puzzles and word games, might help to bolster the brain. Results from the Taxi Brains study are expected later in 2022.

By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.

Source: University College London, Institute of Behavioural Neuroscience in the Department of Experimental Psychology, led by Professor Hugo Spiers.


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