Brain ‘buffer’ may control premenstrual moods

An emotional buffer zone in the brain may not be working as it should in women who experience premenstrual moodiness, a new study suggests.

David Silbersweig and colleagues at the Weill Medical College of Cornell University, New York, US, used functional magnetic resonance imaging to scan the brains of 12 women whose moods remained steady throughout their menstrual cycles. From 1 to 5 days before menstruation, and 8 to 12 days after, the women’s brains were scanned as they were shown printed words with either negative, neutral, or positive connotations – words like “rape”, “cancer”, “bookcase”, “rotate”, “gentle” and “delighted” – to engage the emotion-processing part of the brain.At the same time, the women were motivated to complete a simple cognitive task. The scans showed that the orbitofrontal cortex – part of the brain involved in controlling emotions and regulating motivation – was more active during the task in the days before menstruation. After menstruation, that part of the brain was relatively inactive during the task.Silbersweig says that the difference in brain activity may “buffer” hormonal changes in these women, helping them to maintain a consistent emotional state. “Because this area is kicking in, these women may be able to avoid moodiness across the menstrual cycle,” he says. Brain trainThe 12 women involved in the trial were not taking the contraceptive pill, nor were they on psychoactive drugs such as Prozac. But the implications of the study are far wider.For anyone, male or female, who experiences moodiness, says Silbersweig, “this study suggests that there are areas involved in regulating emotions that are functioning differently”.And the researchers raise the possibility that the brain can be “trained” – that moody people might be able to activate the buffer zones in their brains necessary to iron out moodiness.”Theoretically that may be possible,” says Silbersweig. “Our work can help set the stage for this sort of cognitive behavioural therapy.”(Source: Proceedings of the National Academy of Sciences (vol 102, p 16060): New Scientist: Rowan Hooper: October 2005.)