Friday, May 12, 2017

The brains of taxi drivers

Here is one definition of “neuroplasticity”: The brain’s ability “to reorganize itself by forming new neural connections throughout life.” Neurons, also called nerve cells, can compensate to some extent for head injuries as well as neurological damage caused by diseases such as Parkinson’s and Alzheimer’s. At one time, scientists thought that neurons (nerve cells) were finite. But now we know there are ways to continually give birth to neurons throughout one’s life.
Earlier this week I paid $8 to obtain an article in the venerable  British science journal Nature, titled “Probing plasticity.” But I would be lying if I claimed to fully understand this text. It was written in a scientific dialect that would have taken days, maybe weeks, for me to learn. At the other end of the spectrum, I consulted the website Neuroscience for Kids, which noted that the human brain has roughly 100 billion neurons at any one time. An interesting fact, but one that failed to illuminate neuroplasticity.
Elsewhere, I learned that DARPA—the U.S. Defense Advanced Research Projects Agency—plans to collaborate with seven public research universities to develop better ways to explore how “stimulation of the human body’s peripheral nerves can help facilitate cognitive learning.” In the fifteen-plus years since 9/11, many soldiers have been diagnosed with traumatic brain injuries.
Most relevant on this topic is an article by Carolyn A. Scott, who works on behalf of Rainbow Rehabilitation Centers. “An individual who experiences a traumatic brain injury may also experience deficits in cognition,” Scott wrote in a lengthy article. “To better understand how the brain works and recovers from an injury, we must have an understanding of how the brain learns and adapts to experience. This understanding may also help us determine which treatments are most effective.”
 Two studies completed in the early years of this century have proven illuminating. In the first study, published in 2000, established that taxi drivers in London needed three to four years to master all the routes within the metropolis. In a second study (2003), the researchers concluded that the immense time the drivers spent on the road over the years increased their brains’ gray matter, making them, for want of a more precise term, more intelligent. Particularly impressive were the gains in short-term memory, which resides in the bilateral hippocampus—the part of the brain that, in cases of Alzheimer’s, typically experiences the first effects of the disease.
For the legions of veterans who have sustained serious brain  injuries in combat in Iraq or Afghanistan over the past fifteen years, neuroplasticity is a crucial concept. According to the medical definition of plasticity, the brain has the ability “to reorganize by forming new neural connections throughout life.” Neuroplasticity allows nerve cells in the brain and adjust their activities to new situations or to changes in the environment.” In other words, some brain damage that once would have regarded as permanent now can be treated.

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