A new study shows that women use their brains differently at different times of the month. Using MRI for brain scans, scientists have revealed that mental processes can change across the menstrual cycle.

The research involved 12 women who were supposed to read words with negative, neutral or positive connotations premenstrually- one to five days before their period and also postmenstrually - eight to 12 days after their period.

Researchers used MRI scans to monitor the brain activity patterns of women as they were asked to perform these tasks.
The scans showed that women had much greater activity in frontal brain regions that help control emotions when they were reading the emotional words premenstrually and that this activity had disappeared postmenstrually.

It seems as if women are more prone to emotional instability after their periods than during the PMS as previously thought.