19:00 07 November 02

Alcohol's erroneous ways revealed

by Emma Young

Just two glasses of wine can ruin your brain's ability to detect its own errors, and to correct them. The finding helps explain why alcohol so severely impairs driving ability, and casts new light on the basic action of the drug on the brain, says a Dutch team.

"We all know on a subjective level what alcohol does - we lose control a little bit, we become more error-prone. But this research gives a new perspective on how alcohol has these effects," researcher Richard Ridderinkhof of the University of Amsterdam told New Scientist.

Ridderinkhof's team studied people performing a lab task designed to generate a high proportion of errors. They found that alcohol had a significant effect on activity in the anterior cingulate cortex (ACC), a region known to be involved in detecting errors and in signalling a need to adjust performance after an error.

Just two units of alcohol reduced by a third the amplitude of the brainwave generated from this region following an error. "This means people either detect errors less often or less efficiently, or both," Ridderinkhof says.

Lane drifting

But the alcohol also affected people's ability to modify their performance following an error: "With alcohol, this response is so diminished it is almost completely gone," he told New Scientist

It is not difficult to see how such alcohol-fuelled brain changes could be disastrous for drivers, Ridderinkhof adds: "Think of drifting a bit into another lane. Then, you would have to correct this error quickly and maybe slow down a bit to make sure you don't make similar further errors" The new work shows why alcohol reduces this ability.

However, other effects of alcohol on the brain, such as impaired reaction times, are also involved in explaining the danger of drink-driving.

Ridderinkhof team is now investigating the effects of caffeine and other drugs on the ACC. The brain transmitter dopamine is important for generating the error-related responses. So drugs that interfere with dopamine, such as amphetamines, might also interfere with these responses, he says.

Journal reference: Science (DOI: 10.1126/science.1076929)

19:00 07 November 02

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