Study, 2019
Does the brain work differently at different points in the menstrual cycle?
Yes, brain activity patterns shift across the menstrual cycle even though task performance stays the same. Estradiol seems to boost activity in a memory-related brain area before ovulation, while progesterone boosts activity in planning-related areas in the second half of the cycle.
What they did
Thirty-six women with natural (non-hormonal) menstrual cycles had brain scans (functional MRI) while doing two thinking tasks, one involving finding your way around and one involving coming up with words, at different points in their cycle.
What they found
There was no clear difference in how well women performed the tasks across the cycle. But brain activation patterns changed in a similar way for both tasks: estradiol was linked to more activity in the hippocampus (a memory-related area) before ovulation, and progesterone was linked to more activity in frontal and striatal brain areas during the second half of the cycle. Connections between the two sides of the brain's frontal areas also changed, which seemed to help calm down hippocampus activity.
What it means for you
This suggests the brain's activity patterns adapt across the cycle even when actual performance does not change, which could help explain why some women notice shifts in how their thinking feels at different times of the month. The study was small, with only 36 women, so the findings need to be confirmed in larger groups.
36
Number of women studied
2
Cognitive tasks tested
About the study
- Original title
- The cycling brain: menstrual cycle related fluctuations in hippocampal and fronto-striatal activation and connectivity during cognitive tasks
- Authors
- Pletzer B, Harris TA, Scheuringer A et al.
- Journal
- Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
- Year
- 2019
- Study design
- Study
- What was tested
- Brain scans during two thinking tasks, compared across menstrual cycle phases
- Open access
- Yes
- Read the paper
- doi.org/10.1038/s41386-019-0435-3
Original abstract
Estradiol and progesterone vary along the menstrual cycle and exert opposite effects on a variety of neurotransmitter systems. However, few studies have addressed menstrual cycle-dependent changes in the brain. In the present study we investigate menstrual cycle changes in brain activation and connectivity patterns underlying cognition. Thirty-six naturally cycling women underwent functional MRI during two cognitive tasks: spatial navigation and verbal fluency. While no significant performance differences were observed along the menstrual cycle, the changes in brain activation patterns are strikingly similar during both tasks. Irrespective of the task, estradiol boosts hippocampal activation during the pre-ovulatory cycle phase and progesterone boosts fronto-striatal activation during the luteal cycle phase. Connectivity analyses suggest that the increase in right-hemispheric frontal activation is the result of inter-hemispheric decoupling and is involved in the down-regulation of hippocampal activation.
Reproduced under CC-BY.