With the holiday season around the corner, no doubt, you'll be sharing the nation's highways with senior citizens traveling in cars way too big for them, distracted mini-van drivers on mobile phones attempting without success to shush their loud, crying children into momentary silence and high school students learning the rules of the road for the first time. But, these are not the only species of drivers you need to avoid. In fact, the particular kind of bad driver identified in a recent study may be much harder to identify albeit on the surface.

University of California, Irvine researchers have discovered a gene variant, present in some 30 percent of all Americans, that may responsible for poorer driving habits.

This variant reduces the availability of a brain protein known as brain-derived neurotrophic factor (BDNF) that strengthens memory by supporting communication among brain cells and maintaining optimal functioning. Previous research has shown patients with this BDNF gene variant don't recover as well from strokes and smaller portions of their brains, than normal, are stimulated by doing a given task.

Scientists tracked the results of two simulated driving tests (requiring participants to drive 15 laps on a track programmed with difficult turns and curves) assigned to 29 patients, including seven with the gene variant, within a four-day span. Generally, folks with the BDNF gene variant performed worse than those without it on both driving tests, and recalled fewer details about the track's intricacies the second time out.

Fortunately, there's a silver lining to this genetic predisposition to bad driving: Those who have it hold onto their mental sharpness longer in the presence of MS, Huntington's, Parkinson's and other neurodegenerative diseases.

Cerebral Cortex September 10, 2009

EurekAlert October 28, 2009