Tuesday, April 29, 2008

My Brain on Booze

A unique EEG test reveals how alcohol sets the brain aglow.

By Emily Singer

Brain waves: Biotechnology editor Emily Singer wears a cap fitted with EEG electrodes, designed by Alan Gevins and his colleagues at SAM Technology. The device assesses brain function as Singer plays a series of specially designed computer games. Credit: Kate Greene

It's noon on a sunny day in San Francisco, and I'm trying to down a double vodka cranberry as fast as I can. Despite reporters' reputation, drinking is not my typical lunchtime activity. Today I'm visiting neuroscientist Alan Gevins, who has spent the past 40 years developing better ways to analyze the electrical signals emanating from our brains and, in turn, to study how our ability to remember and pay attention changes with different drugs, with the neural glitches of disease, and with the decay of age. In 20 minutes or so, when the alcohol has brought my brain to its peak boozy state, Gevins's team will measure how it has impacted my neurons as they struggle through a series of memory tests.

Electroencephalography (EEG) is a decades-old technology used to measure electrical activity produced by the brain via electrodes placed on the scalp. In recent years, enhanced computing power and increasingly sophisticated software have allowed scientists to more precisely record and analyze these signals, giving a much greater insight into the meaning behind the brain's electrical storms. Currently, EEG is used both clinically--to identify the source of seizures in epilepsy patients, for example--and for research, such as to characterize the brain's rhythmic activity during sleep, relaxation, and concentration.

Gevins, founder of SAM Technology and the San Francisco Brain Research Institute, has developed a system that combines EEG with cognitive testing--computer tests that assess a person's memory or ability to multitask--to get a more direct measure of the brain's ability to remember and pay attention. He is now aiming to commercialize the technology, with the eventual goal of using it to more precisely assess cognitive decline and tailor drug prescriptions to minimize cognitive side effects. The technology incorporates both new hardware, to measure electrical activity, and new software, to process those signals.

Previous research by the group suggests that drinking may be more detrimental to our ability to function than previously thought. The brain effects of alcohol remain two to three hours after the behavioral effects have disappeared, even when blood alcohol level is as low as 0.02 percent, about a quarter of the legal limit for driving in most states. "You might be able to summon short bursts of attention and perform well on a short test, but the brain is still abnormal," says Aaron Ilan, principal neuroscientist at SAM Technology. "You won't be able to fully focus on a task like driving for several hours."

The team is now finishing a large study looking at the effects of alcohol, marijuana, caffeine, and diphenhydramine, the active ingredient in Benadryl, on simulated driving, as well as on attention, working memory, and the ability to multitask. The findings should shed light on the cognitive effects of these drugs. While alcohol's effect on driving is well studied, the same is not true for most prescription drugs.