Brain imaging study of drunk drivers pinpoints neurological changes

Imaging studies of the brain when it is under the influence of alcohol reveal that different areas of the brain are
impaired under high and low levels of alcohol, according to a Yale study published in Neuropsychopharmacology.


Godfrey Pearlson and Vince Calhoun, researchers in the Department of Psychiatry at Yale School of Medicine, used a
statistical method to sort areas of the brain affected when persons were administered a placebo or two different doses of
alcohol. The seven men and two women then "drove" using a simulated driving skill game.


"What we found is that when people were really intoxicated, they drove like they were really intoxicated and in a real
vehicle," Pearlson said. "They speeded up, especially on corners, where most people slow down, and crashed more often into
other vehicles." When mildly intoxicated, but below the legal alcohol limit, he said, the drivers seemed aware of the fact
that they were impaired and corrected for the deficit. The researchers also found that alcohol had a profound effect on some,
but not all, brain circuits activated in sober driving.


The areas most profoundly affected by alcohol were the orbital frontal and anterior cingulate areas, which help control motor
functions. The medial frontal regions of the brain involved in making decisions, and working memory, were not affected until
the person was beyond the legal limit of intoxication. A function of working memory might be to find one's way home, the
researchers said.


Impairment of the cerebellum area of the brain, which related strongly to speeding, was clearly correlated with the alcohol
dose. Changes in the frontal and parietal cortex, which govern alertness and attention, were correlated with weaving while
driving.


The highest blood alcohol level was 0.1 and the lowest was 0.05. Drivers are considered legally drunk when their blood
alcohol level is 0.08.


Citation: Neuropsychopharmacology, Vol. 29 (11): pp 2097-2117 (November 2004)


Contact: Jacqueline Weaver

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203-432-8555

Yale University