Subjects drink and drive for science

For a recently published study, test subjects were paid to do what many college students do on a regular basis — get drunk and play video games.

The Yale School of Medicine’s Department of Psychiatry brain-scan study found that different areas of the brain are affected by high and low levels of alcohol consumption prior to driving. Vince Calhoun, the principal analyzer of the data and assistant clinical professor in the Yale Department of Psychiatry, said the study focused on changes in driving behavior and brain function accompanying different alcohol doses.

“It’s the first look at what brain regions are involved when you drive, and it gives us an inside look at where these changes are occurring,” Calhoun said. “We know alcohol affects us, but we didn’t know what part of the brain was affected.”

The study, appearing this month in Neuropsychopharmacology and administered during 2001 and 2002 at Johns Hopkins, used an MRI to scan the neurological activity of seven men and two women playing the video game driving simulator “Need For Speed 2.” The subjects each played four times — once while sober, and then with 0.04, 0.08 and 0.1 blood alcohol levels.

Having designed the experiment together with Calhoun, Yale psychiatry professor Godfrey Pearlson, who is in charge of the behavioral aspects of the study, said people with the low alcohol blood content of 0.04 did not drive much differently from sober driving, and in some cases, drove slightly better.

“People report that in real life they’re aware that they’re slightly intoxicated, so they drive more carefully to compensate,” Pearlson said.

He also said legally drunk subjects with a blood alcohol content of 0.08 acted more drunk — crashing into other vehicles, speeding and weaving.

Calhoun said the behavioral results correlated with the neurological findings, and the researchers were able to match changes in particular regions of the brain with changes in driving.

“We found not a whole lot that was changing in the brain circuits at a low dose, except for a small change in the orbital frontal cortex, which controls inhibition and monitors errors,” Calhoun said. “At the high dose of 0.08, we found significant changes in that same region but also in the orbital frontal and anterior cingulate areas which control motor functions.”

Only at a blood alcohol level of 0.1, past the legal limit of 0.08, did the medial frontal regions of the brain, which affect decision making and working memory, become impaired by alcohol, Calhoun said.

The researchers also said they found that some but not all brain circuits activated during sober driving were affected by intoxication. Pearlson said alcohol’s effects on the cerebellum was closely related to speeding.

Responding to controversy about the legally drunk blood alcohol limit — the previous legal limit was 0.1 — Calhoun said the study demonstrates 0.08 is not too low.

“We’re finding significant changes with 0.08 which shows 0.08 is an accurate limit,” Calhoun said.

Both researchers said they will be continuing the study at the Olin Neuropsychiatry Research Center at the Institute of Living in Hartford with additional variables, a stronger imaging scanner and an improved simulation.

A research assistant in the lab, Matt Johnson ’03, has tried the new simulator at the Olin Center. The simulator replaces the game controller with a steering wheel and foot pedals.

“It’s pretty much as close as you can come in a simulation of an artificial environment, though you’re never going to have the 3-D effect,” Johnson said.

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