Impact of the Menstrual Cycle on the Brain

Sex hormones cause changes in central learning and memory hubs. Rachel Zsido and Julia Sacher of the Max Planck Institute for Human Cognitive and Brain Sciences and the University Clinic in Leipzig, Germany, published a new study in Nature Mental Health that links rhythmic oscillations in ovarian hormone levels in women during the menstrual cycle to changes in brain structure.

Ovarian hormones have major impacts on the brain, and early menopause may be related with an increased risk of dementia and accelerated brain aging later in life. The consequences of ovarian hormone changes on brain shape earlier in life, on the other hand, are less well characterized. Rachel Zsido and Julia Sacher reveal in their present study that ovarian hormone variations impact structural plasticity in critical brain regions during the reproductive years.

To accomplish this, the researchers gathered blood samples from 27 female study participants, used ultrasonography to detect follicle growth in the ovaries to determine ovulation timing, then zoomed into subregions of the medial temporal lobe and hippocampus using ultra-high field 7 Tesla MRI. This is because these areas are densely packed with sex hormone receptors and are essential for cognitive functions like episodic memory.

Detecting dynamic variations in sexual hormones
Unlike prior investigations, Zsido and Sacher investigated female brains at six different periods during the menstrual cycle. This longitudinal design depicts the dynamic changes in sex hormones: estradiol rises during the first half of the menstrual cycle and peaks around ovulation, while progesterone dominates the second half. Estradiol is one of the most essential sex hormones in the female body, and it plays a crucial role in the reproductive system’s maintenance. Progesterone is another important reproductive sex hormone that prepares the uterus for pregnancy and provides anxiety-relieving, sleep-inducing, relaxing, and calming properties. As a result, the female brain is accustomed to a steady pattern of hormones, which this research study analyzes for the first time.

“We discovered that certain medial temporal lobe regions, which are important for episodic memory and spatial cognition, expand when estradiol levels are high and progesterone levels are low – that is, these brain areas remodel themselves in sync with the menstrual cycle.” In multiple follow-up investigations, we hope to determine whether these rhythmic alterations are altered in persons at risk for memory and emotional disorders,” explains Julia Sacher. “The female brain is still vastly understudied in cognitive neuroscience.” Despite the fact that sex steroid hormones are potent modulators of learning and memory, hormonal transition phases such as the menstrual cycle, the influence of hormonal contraceptives, pregnancy, and menopause are covered in less than 0.5 percent of the neuroimaging literature. We are devoted to filling this critical research gap. We need a better knowledge of how the healthy female brain adjusts to change in order to determine the mechanisms behind risk and resilience to mental health problems like depression or Alzheimer’s disease.

Source Link