Brain Images Reveal Menstral Cycle Patterns

Brain Images Reveal Menstrual Cycle Patterns

For the first time, scientists have pinpointed an area of the brain involved in a woman's menstrual cycle. The research, reported online this week by the Proceedings of the National Academy of Sciences, shows contrasts in activity over the course of a month and provides a baseline for understanding the emotional and behavioral changes that 75 percent of all women report experiencing before, during and after their period.

To capture the activity, Protopopescu examined 12 healthy women between the ages of 22 and 35 while they read a series of negative, neutral and positive words meant to illicit emotional responses. The women were tested before and after their periods and were specifically selected as females who reported having no premenstrual mood symptoms--characterized as irritability, tension, depression, loss of control, sleep-disturbance, fatigue, food cravings, physical symptoms and social withdrawal--in order to provide Protopopescu with a foundation for future studies of women with symptoms.

The scientists found that during the one to five days before menses, the subjects showed greater activity in the middle front part of the brain region and less activity on the sides. After menses, more activity occurred on the sides with less activity showing up in the middle front area. The women reported feeling no mood changes throughout the month, so the researchers offer another explanation for the shift in activity. "Because of what's known about these regions, we speculate that the increase in activity is in some way modulatory," says team leader David Silbersweig, vice chairman for research in Cornell's Department of Psychiatry.

According to the report, the reallocation of activity from one part of the brain region to another may reflect the organ's ability to compensate for hormonal changes and help a woman maintain a consistent emotional state. The scientists are now working to compare these results with imaging work on subjects that experience more severe premenstrual mood symptoms.