‘Menstrual’ brain changes seen
Last Updated: Tuesday, 25 October 2005, 09:28 GMT 10:28 UK
Women use their brains differently at different times of the month, research suggests.
Brain scans revealed mental processes can change across the menstrual cycle.
Just before a period, at the time when some women experience premenstrual syndrome, activity in brain regions that help control emotions increased.
After menstruation the activity went down, a US team from New York told Proceedings of the National Academy of Sciences.
Although the researchers looked at 12 women with no outward menstrual mood changes, they say their findings could be important for understanding why some women have a particularly hard emotional time around menstruation.
PMS is believed to affect between one-third and one-half of women between 20-50 years of age.
Women with PMS may experience depression, irritability and a propensity towards outbursts of anger as well as physical symptoms such as cramps and bloating.
It confirms that the psychological health of women patients must be assessed in relationship to the menstrual cycle
Chris Ryan of the National Association for Premenstrual Syndrome
In the study, Dr Emily Stern of Cornell University, along with colleagues from the Rockefeller University, used MRI scans to monitor the brain activity patterns of women as they were asked to read words with negative, neutral or positive connotations.
The 12 women were asked to perform the same task premenstrually – one to five days before their period was due – and then postmenstrually – eight to 12 days after their period.
During the premenstrual phase the women showed much greater activity in frontal brain regions that help control emotions when they were reading the emotive words.
Postmenstrually, this increased brain activity had disappeared.
The researchers say it is possible that the brain changes might have allowed the women to maintain a consistent emotional state and compensate for the surging hormones that occur around menstruation, which some suggest are involved in PMS.