Fifteen years ago, a now-famous study discovered that the brain area associated with navigation—the hippocampus—was greatly enlarged in London cab drivers.
It was never clear if their hippocampi grew because they learned to navigate around London, or if they became successful cab drivers merely because their hippocampi were larger than normal to begin with. But thanks to a study out of Carnegie Mellon University, we now have answers.
The researchers recruited 28 adults and taught them to play a video game that simulated driving.
From these 28 adults, two groups were created: a control group, which drove 20 different routes over the course of 45 minutes, and a so-called spatial learning group, which drove one route 20 times for 45 minutes.
Or, in other words, the control group drove without the ability reinforce routes they had learned, while the spatial learning group reinforced one route repeatedly—thereby actually allowing them the time and repetition necessary for memory.
The scientists scanned all 28 participants’ brains both before and after their driving tasks. According to the study, which is published in NeuroImage, they discovered that only the spatial learning group showed changes in a specific part of the hippocampus that is key for spatial learning: the left posterior dentate gyrus. There was also an increase in connectivity and synchronization between this part of the hippocampus and other brain regions responsible for spatial cognition.
Further, the participants were better able to order a sequence of random pictures taken along the route and to draw a 2D map of the route. The spatial learning group also increased their speed at completing each driving task more than the control group—and, the amount of change that occurred in the hippocampus was directly related to the behavioral improvement the participants showed in driving.
“The new discovery is that microscopic changes in the hippocampus are accompanied by rapid changes in the way the structure communicates with the rest of the brain,” explained Marcel Just, co-author and psychology professor at Carnegie Mellon University, in a statement. “We’re excited that these results show what re-wiring as a result of learning might refer to.
“We now know, at least for this type of spatial learning, which area changes its structure and how it changes its communication with the rest of the brain.”
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Image credit: Thinkstock
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