Alcohol Linked to Distinct Brain Changes, Even in Moderate Amounts
In addition, while the study suggests that specific areas of the brain react differently to high levels of alcohol versus lower amounts, all drivers seemed to be affected by alcohol regardless of the amount consumed. Yale University School of Medicine researchers Vince Calhoun, and Godfrey Pearlson, Department of Psychiatry, studied the effect of two different amounts of alcohol on a group of nine individuals. The study, published in Neuropsychopharmacology, involved giving either alcohol or a placebo, then asking participants to attempt to drive using a simulator.
Described to look like blinking lights, the varying brain activity of participants was captured with imaging as they consumed different levels of alcohol and tried to drive. These images were compared to those taken from simulation drivers who had not been drinking. According to Pearlson, these images have not been captured before.
Some participants were given levels of alcohol high enough to exceed the legal limit, reaching nearly 10 percent; others received much lower amounts. Pearlson noted that people who were intoxicated made distinctly different decisions than people not under the influence during the simulated exercise. For example, they went faster on corners instead of reducing their speed and crashed into other cars more often.
However, when participants were given only moderate amounts of alcohol – not enough to be officially intoxicated – they seemed to be more careful with the driving simulator because they realized they were under the influence. In addition, the study suggests that not every brain circuit is affected the same way. Some brain circuits for normal driving were highly affected by alcohol, while others used for driving sober were not.
Researchers took detailed looks at which parts of the brain were most affected by drinking, and how it impacted behavior. Overall, the brain areas responsible for motor functions – the orbital frontal and anterior cingulated regions – were more affected than other areas of the brain. They also observed that it wasn’t until participants’ levels of intoxication went past legal amounts that parts of the brain that control memory and decision-making showed signs of trouble.
Additional findings concluded that modified responses in the cerebellum of the brain, which controls decisions like driving too fast, were distinctly connected with the amount of alcohol consumed. Furthermore, as participants were observed weaving on the road, researchers saw changes in the portions of the brain that control attention and sense of alertness. This study reveals surprising connections between altered driving and brain activity, even on moderate amounts of alcohol, and suggests that alcohol may impact drivers’ behavior and awareness in more ways than previously thought.