Have you been guilty of more than one minor car accident involving an inanimate object? Do you frequently observe passengers in your car holding on to that little handle between the window and the windshield (the "Oh s***" handle, as one of my friends likes to call it) until their knuckles turn white? Do your family members and acquaintances routinely refuse to let you operate their motor vehicles?
If you answered yes to any of these questions, you might be a bad driver. But a new study published recently in the journal Cerebral Cortex suggests that your genes may be to blame.
People with a gene variant limiting the availability of a protein called brain-derived neurotrophic factor (BDNF) performed more than 20 percent worse on a driving test than people without it. A follow-up test a few days later had similar results.
BDNF works to keep memory strong by supporting brain cell communication. When you are engaged in a task like driving, BDNF is secreted in the area of the brain responsible for the function and helps your body respond.
About 30 percent of Americans have the genetic variant. Previous studies have shown that people who have it experience stimulation in a smaller portion of the brain than those with a normal BDNF gene. This led scientists at the University of California, Irvine to wonder if it could affect a common activity such as driving, which has a learning curve and is something that most people know how to do.
They conducted the driving test using 29 people — seven with the variant and 22 without it. The participants drove 15 laps on a simulator that required them to learn the details of the track, and researchers recorded how well they stayed on the course. They repeated the test four days later.
Participants with the variant did worse on the test both times they took it, and they remembered less than their variant-free counterparts on their second trial. In a university release, Steven Cramer, associate professor of neurology and senior author of the study, said, "Behavior derives from dozens and dozens of neurophysiologic events, so it's somewhat surprising that this exercise bore fruit."
Having the variant is not always a bad thing, however. Although those who have it do not recover as well from strokes as those without it, they do maintain their mental sharpness longer than others when affected by neurogenerative diseases such as Parkinson's, Huntington's and multiple sclerosis.
There is currently no commercially available test to determine whether or not someone has the variant, but Cramer says he'd be interested to know the genetics of people who are involved in car crashes.
Maybe the next time a bad driver cuts you off on the freeway, you should consider expressing a little tolerance — after all, it may be genetic.
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