Menstrual cycles can be complex for many, with constant dysmenorrhea, more commonly known as cramps, followed by various symptoms, including nausea, headache, and vomiting. These physical symptoms, however, are not the only things that the menstrual cycles brings.
During menstustion, the brain is significantly impacted by ovarian hormones, and early menopause may raise the chance of dementia and accelerated brain aging in later life.
Less is known, meanwhile, about the early-life impact of ovarian hormone variations on brain anatomy. At the University Clinic in Leipzig, Germany's Rachel Zsido and Julia Sacher conducted a study published in the journal Nature Mental Health.
They demonstrated how changes in ovarian hormones impact structural plasticity in essential brain areas over the reproductive years.
The researchers took blood samples from 27 female study participants, tracked the formation of follicles in the ovaries using ultrasound to determine the exact time of ovulation, and employed ultra-high field 7 Tesla MRI to focus on specific areas of the medial temporal lobe and hippocampus.
These areas are essential for cognitive processes like episodic memory and are rich in sex hormone receptors.
In contrast to earlier research, Zsido and Sacher looked at the female brain six times during the menstrual cycle.
Menstrual cycle and the brain
Estradiol, whose main function is to mature the reproductive system, rises throughout the first half of the menstrual cycle and peaks around ovulation, whereas progesterone predominates during the second half of the process. Progesterone helps the uterus get ready for pregnancy and also has soothing, relaxing, and anxiety-relieving properties. The hormonal roles capture the dynamic changes in the body.
The female brain is tuned to a continuous cycle of hormones, which this research study traces for the first time, much like the tide's ebb and flow.
"We were able to determine that certain medial temporal lobe regions, which are crucial for episodic memory and spatial cognition, expand under high estradiol and low progesterone levels - that is, these brain areas remodel themselves in synchronization with the menstrual cycle. We want to clarify whether these rhythmic changes are altered in individuals at risk for memory and affective disorders in several follow-up studies."- Julia Sacher
She says there is still a need for more research in cognitive neuroscience on the female brain in general. Less than 0.5 percent of the neuroimaging literature considers hormonal transition stages, such as the menstrual cycle, the impact of hormonal contraception, pregnancy, and menopause, even though sex steroid hormones are potent modulators of learning and memory.
The team concludes that they're determined to fill this critical research void and continue to strive for a better knowledge of how the healthy female brain adjusts to change to pinpoint the mechanisms underlying risk and resilience to mental health problems like depression and Alzheimer's disease.
- Nature Mental Health. Ultra-high-field 7T MRI reveals changes in human medial temporal lobe volume in female adults during menstrual cycle.
- American College of Obstetricians and Gynecologists. Dysmenorrhea: Painful Periods.