European grant for Ellen de Bruijn: ‘Hormonal fluctuations in women have been ignored for too long in brain research’
Psychologist Ellen de Bruijn studies the effects of hormonal fluctuations on behaviour and on the brain over a woman's life course. With an ERC Consolidator grant, she and 3 PhDs and a postdoc will work further on her EEG research on the different stages at which girls and women experience strong hormonal fluctuations.
Her ERC grant application opened with the 2019 Women's World Cup. After the tournament, the staff of the winning US team reported that all players' menstrual cycles were monitored and their schedules for training, nutrition and rest were adjusted accordingly. 'A top team takes this kind of fluctuation in women into account. Why is this news in 2019?’ de Bruijn asks in amazement.
Why have the effects of female hormones been ignored for so long?
‘Until recently, people assumed that sex hormones only affected the reproductive organs. Now, however, we know primarily from animal studies that they also have an influence on the brain. Even so, hormonal fluctuations, such as during the menstrual cycle or menopause, are still being ignored in many studies, although this is certainly not always done intentionally. However, women are still excluded from some studies, for example in psychopharmacological research, where we want to determine the effects on behaviour and the brain by administering certain substances or medication. The idea behind this exclusion is that we don't yet know how hormonal fluctuations affect the functioning of neurotransmitters in the brain, but only including men is obviously no solution to this gap in our knowledge.'
What is your research about?
'In my research, I look at the main hormonal transition phases and fluctuations in women and whether they affect processes in the brain. Women are differently affected by psychological disorders than men. Anxiety disorders and depression, for example, are more common in women, but the symptoms, severity and course of the disorder also very often differ between men and women. We also see that hormonal transition phases, such as puberty, the menstrual cycle and the transition to menopause, are often associated with an increased risk of mental health problems. But we don't yet fully understand how they are linked. As part of this project, I want to conduct the first large-scale study of these three important transitional phases in a woman's life.'
Can you explain that?
'The increase in the sex hormone estradiol heralds the beginning of the fertile period and declines again later in life at menopause. This hormone also shows monthly fluctuations, but these are much more subtle than in the transition phases. I plan to include girls and women aged 8 to 60 in my research and measure their behaviour and brain activity as they perform various tasks that are important for everyday and social functioning. For example, what happens when they make a mistake? Are they able to learn from it, do they know how to respond flexibly to their environment? What do they do when a mistake affects other people? These rapid reactions and processes can be measured perfectly with EEG. We already have a lot of experience with these tasks, and we have a good idea where in our brains these processes take place and which neurotransmitters, especially dopamine and oxytocin, play a role in them.
‘We are going to follow and observe the youngest age group over a longer period. In the two older age groups, I will use pharmacological manipulations. What happens when you increase estradiol, dopamine or oxytocin in a particular phase of the cycle and what effect does this have on the brain and behaviour? Hormone replacement therapy by increasing estradiol is an important treatment during the transition to menopause, but we don't really know what the effects of this are on women's neurocognitive functioning. So it is important to study that properly.'
What is the societal relevance of this research?
‘I want to use my research to help us gain an overall understanding of what factors contribute to health and well-being in women of all or almost all ages and how they are able to carry on functioning optimally. What people generally say about the menopause is that it‘s a phase you just have to go through. More or less the same applies to the menstrual cycle and related symptoms. A better approach is to understand what is going on, what helps and what doesn't, and also to communicate this properly to the girls and women themselves. This is also an important additional aim of the project: not only to connect researchers in this broad interdisciplinary research field, but also to properly inform the target groups, i.e. girls and women of all ages, and where possible actively involve them in the research.'
Do you have any idea why ERC has honoured your funding application?
'This type of research is hugely interdisciplinary. Now is the time to combine all the recent insights from all these separate disciplines, such as endocrinology, animal research, neuroimaging, and psychopharmacology, and that is what I did. This interdisciplinarity is great, but it can sometimes be tricky with reviewers from all sorts of backgrounds: medical, psychological and sociological. There can be endless discussions about which is better, hormone analysis via saliva or blood samples? There is a lot of progress to be made here in the coming years. It's a huge but also fun challenge to harmonise all these different research methods.'