Researcher scans her brain 75 times to find out how the brain reacts to contraceptives

The preliminary results of this study, which Heller presented at the annual conference of the American Society for Neuroscience and are collected in an article in the journal ‘Nature’, suggest that both brain morphology and connectivity fluctuate daily throughout the lifespan. menstrual cycle, and that the contraceptive pill influences these variations.

Heller is part of a growing group of researchers seeking to fill gaps in knowledge about women’s health, especially related to oral contraceptives and their effects on the brain, a historically neglected area. Its goal is to generate more data that will allow women and doctors to make more informed decisions about the use of these drugs, and about which formulations may be most appropriate for each person. “We want to give women tools to better understand how their bodies and brains react to contraceptives,” says Heller, a researcher at the University of Minnesota Twin Cities in Minneapolis.

Emily Jacobs, a neuroscientist at the University of California, Santa Barbara and Heller’s collaborator, highlights the researcher’s dedication: “She dedicated herself to science in an extremely rigorous experiment, which has given us a new level of understanding about how the brain works.” human brain.” Through her personal experimentation, Heller became a subject and scientist, harnessing her own body to generate data on how oral contraceptives influence brain structure and functionality.

Elizabeth Chrastil’s team set out to study changes in a woman’s brain during pregnancy. To do this, Chrastil underwent 26 magnetic resonance imaging (MRI) and blood tests that began three weeks before conception and extended throughout the three trimesters of pregnancy, until two years after the baby was born.

This researcher from the University of California-Irvine recognized that “being able to contribute to science as a neurologist, knowing how much we still don’t understand, was the most exciting thing. I decided to say “let’s do it,” get pregnant and see what happens. It was amazing to see the changes in my own brain, but also to realize that everything was okay. “I was able to experience these changes, become a mother and realize that all this is part of life and nature.”

“This study is pioneering because it shows how the brain changes week by week, from before pregnancy to two years after giving birth,” said Jacobs, from UC Santa Barbara (USA) and one of the authors of this study published in a few months ago in ‘Nature Neuroscience’.

Contraceptives

Oral contraceptives, introduced in the 1960s, have transformed the lives of millions of people by regulating the menstrual cycle and preventing pregnancy through synthetic hormones such as progesterone and estrogen. Despite its widespread use by more than 150 million women, little is known about its effects on the brain. Data on its psychological impact are contradictory: some people experience a decrease in anxiety and depression, while others report the opposite, without clarity about the causes. This is especially worrying since many women begin using them during puberty, a key period in brain development.

Most neuroimaging studies involve using magnetic resonance imaging (MRI) to examine the brains of between 10 and 30 participants, which are scanned only once or twice. This approach, although effective, does not capture the daily dynamics that the brain experiences throughout the menstrual cycle.

To address this limitation, Heller turned to a methodology known as “dense sampling«, which consists of performing multiple scans of the same individual or a small group over a prolonged period. This system allows obtaining a more detailed set of data, revealing subtle changes that could go unnoticed in more conventional studies. Although dense sampling presents the challenge of working with a limited sample of people, the careful observations it generates offer invaluable insight into brain processes.

In his own case, Heller underwent three rounds of extensive brain scans. During the first phase, you took 25 scans over five weeks, capturing images of your brain at different stages of your natural menstrual cycle. She then started taking oral contraceptives and waited three months to make sure her body adjusted to the drugs. He then underwent 25 new scans. Finally, stopped taking the pill, waited another three months and completed the last series of 25 scans. In parallel, blood was drawn and he completed questionnaires about his mood after each scan, in order to link his hormonal and emotional responses with the changes observed in his brain.

Preliminary results revealed a rhythmic pattern in changes in brain volume and connectivity throughout the menstrual cycle. While on the pill, the volume and connectivity between certain areas of the brain decreased slightly, but these changes do not necessarily correlate with “better” or “worse” brain function. Once she stopped taking contraceptives, the brain pattern largely returned to its natural state, suggesting that the brain is highly adaptive.

Heller’s research is inspired by the work of Laura Pritschet, a cognitive neuroscientist at the University of Pennsylvania, who scanned her own brain for 30 consecutive days while not taking birth control and another 30 days while taking it, in a study she called “28andMe.” (referring to the 28 days of a typical menstrual cycle).

Pritschet, who also collaborated on Elizabeth Chrastil’s study on changes in a woman’s brain during pregnancy published in ‘Nature Neuroscience‘, observed that higher levels of estrogen increase the connectivity of important brain networks, such as the default neural network, linked to dreaming and memory. On the other hand, progesterone seemed to have the opposite effect.

Additionally, Pritschet conducted a study with her husband, called “28andHe,” in which she scanned him for 30 consecutive days to better understand hormonal fluctuations in the male brain. Although these studies only cover a handful of participants, they provide a highly detailed data set that may be the key to understanding individual differences in brain response to contraceptives.

The next step in Heller’s research will be to compare her results with those of women who suffer from endometriosis, a painful disease that affects approximately 10% of women of reproductive age. His goal is to investigate whether the hormonal fluctuations he observed in his own brain could be related to the symptoms of this condition, which could shed light on its origin and possible treatments.

Heller and her team are at the forefront of an area of ​​research that promises to improve understanding of the female brain and the impact of contraceptives on its functioning. This work is not only pioneering in its methodology, but also has the potential to influence the future of reproductive and neurological health for millions of women around the world.

For Susana Carmona, Psychologist and doctor in Neuroscience and leader of the Neuromaternal research group at the Gregorio Marañón Madrid Hospital, the objective of research like this is “to reverse the gap that exists in the scientific literature about how sex hormones modulate activity and anatomy and connectivity of the brain.

Carmona remembers that only “0.5% of all published neuroimaging studies are dedicated to evaluating the effect of hormones at the brain level.”

Carmona works in collaboration with Heller and Jacobs in different consortia to study alleviating the deficit in research on women’s brain health.