Ah, here it is -
Scans pinpoint alcohol's effects on the human brain
Alok Jha, science correspondent
guardian.co.uk, Wednesday April 30 2008
Brain scans have confirmed that alcohol numbs the brain's ability to detect threats while stimulating the regions involved in feeling rewarded.
Jodi Gilman and Daniel Hommer at the National Institute on Alcohol Abuse and Alcoholism in Maryland used functional magnetic resonance imaging to monitor the brain activity of 12 volunteers who had been injected with alcohol. During two 45-minute periods, the participants received either alcohol or a placebo while they were shown pictures of fearful facial expressions.
The researchers focused on brain regions that had previously been identified as being involved in processing threat signals.
They found that when the volunteers were given a placebo, the pictures elicited activity in the amygdala, insula and parahippocampal gyrus - brain regions involved in fear and avoidance - as well as in the brain's visual system. But these regions did not show much enhanced activity when the volunteers were given alcohol.
Gilman and Hommer also showed that the alcohol activated the striatal areas of the brain, which are important components of its reward system. The level of response here was linked to the amount of alcohol a volunteer was given.
"The key finding of this study is that after alcohol exposure, threat-detecting brain circuits can't tell the difference between a threatening and non-threatening social stimulus," said Marina Wolf at the Rosalind Franklin University of Medicine and Science in Chicago, who was not involved in the study.
"At one end of the spectrum, less anxiety might enable us to approach a new person at a party. But at the other end of the spectrum, we may fail to avoid an argument or a fight. By showing that alcohol exerts this effect in normal volunteers by acting on specific brain circuits, these study results make it harder for someone to believe that risky decision-making after alcohol 'doesn't apply to me'."
The findings are published today in the Journal of Neuroscience