Neuroscientists are making strides in mapping and understanding the human brain, but like many other scientific fields, neuroscientific research has suffered from gender bias: men have been studied far more than women.
Since it came on the scene, magnetic resonance imaging (MRI), where a magnetic camera looks through the skull and captures pictures of a living brain, mountains of neuroimaging studies have been made by scientists eagerly delving into the most complex organ we have. It’s led to amazing discoveries and insights, and revolutionised our understanding of how we function.
But the neuroscientific investigation into brain health in relation to conditions only affecting women, girls, and people who have or have had menstrual periods, has been comparably pitifully small.
My name’s Livia. I’m a freelance science writer and journalism student, and I found myself diving into this as I wondered why hormonal birth control, several decades after its invention, still causes negative effects on many users’ moods and well-being. Shouldn't somebody have looked into how our brains get affected when we go on the pill — and created something better?
It turns out that this large neuroscience knowledge gap leaves billions of people in the dark about the organ that creates their lived experiences, affects drug development, and is bad for science, generally.
It’s time for neuroscience to catch up.
Half of one percent
Neuroscientists know fairly little about how pregnancy, menopause, hormonal birth control, and pms or premenstrual dysphoric disorder — to name but a few — affect the brain, compared to other health conditions.
Out of around 50,000 neuroimaging studies completed since the mid-90s, only 0.5 percent have focused on health issues specific to women, says Dr Emily Jacobs, director of the new Ann S. Bowers Women’s Brain Health Initiative at the University of South California, Santa Barbara.
Representation, Jacobs says, has not been a problem. With gender participation in neuroimaging studies remaining at ca. 50 percent, women are just as keen as men to contribute.
Instead, the problem appears to be that many researchers do not study conditions hampering the well-being of people who menstruate, and funders are typically not funding research investigations into health as much as they need them to.
In a 2021 study, mathematician Arthur Mirin showed the National Institute of Health in the United States was not funding the country’s medical research on the grounds of the burden of disease alone — a measurement used to determine how many healthy years are lost to the disease in question — but generally favoured more generously funding illnesses dominated by men, even though their burden of disease was overall smaller.
Dinosaurs and male pattern baldness
As a result of this disparity in neuroscience, Ann S. Bowers Brain Health Institute jokingly estimates humankind knows more about dinosaurs and male pattern baldness than the brains of women and people who menstruate.
It’s tragicomical, but perhaps not surprising when you consider that 80 percent of tenured neuroscientists operating MRI machines are men, as Jacobs says, and the fact that the scientific paradigm of biology and beyond has considered men the baseline standard for decades.
For over 50 years, animals of the biological male sex have been the default in medical research labs across the world, chosen due to concerns that female hormone cycles would affect their behaviours and skew results (a concern later rejected by researchers at Harvard, who showed that female mice actually had more consistent and stable behaviours and should have been used).
The bias of neuroscience has had repercussions for our overall understanding of the human brain as well as drug development and treatment of debilitating illnesses. Certain drugs developed to combat Alzheimer’s, for example, as well as common, over-the-counter drugs, including ibuprofen, appear to work more effectively for men. Women also seem to deal with adverse drug reactions and face side effects more often than men. And, in the high-stakes spaces of emergency rooms and assessment rooms, women are at greater risk of being misdiagnosed, across conditions ranging from stroke to ADHD.
Neuroscience for all
The good news is that, while much unexplored ground remains to be covered, there’s an avalanche of knowledge gathering and progress waiting to be made now — and more neuroscientists are signing up for the work.
Jacobs says the Ann S Bowers Brain Health Institute, for example, plans to collect large amounts of data on the brains of women, trans, and non-binary people, and the U.S. government recently announced they have dedicated 12 billion dollars to women’s health research. We’re learning more about the brain and menopause, hormonal birth control, and other conditions — and slowly crawling closer towards knowing how to more effectively treat conditions that have historically been shrugged at, dismissed, or considered unsolvable mysteries.
Recently, for example, neuroscientific evidence has helped us understand the brain on birth control, suggesting why low mood might occur when on the pill. According to a recently published study, an oral contraceptive pill, widely prescribed for decades, can change brain anatomy.
In the study, the authors, who used magnetic resonance imaging to scan the brains of participants, found that only participants taking the pill had a slightly, yet noticeably, thinner ventromedial prefrontal cortex compared to those who were not on the pill (the effect was, however, reversible). Previous research has shown that the thicker that area is, the better emotional regulation works. Structural changes can also be observed inside the brains of people who go through menopause, alongside changes in brain connectivity and overall energy production, according to a study from 2021.
Researchers have also uncovered hints of potential sex and gender-based differences in depression. Women are around twice as likely to be diagnosed with depression, and it can be incredibly complicated to detangle various causes for depression, with both biological components, such as hormones, and social factors, such as support, likely playing a role. In terms of how depression expresses itself in the brain, a recent review of neuroimaging studies suggests that there may be sex and gender-based hormonal and social factors at play — potential information that could prove to be useful for helping us develop more effective treatments.
While more needs to be done, revealing neuroscience studies into conditions experienced by women and people who menstruate help validate people’s reported experiences. They also give hope that we might soon develop better treatments for things like endometriosis and depression, for example, or hormonal birth control that does not risk chipping away at people’s well-being, which can be deeply intertwined with the health and functioning of our brains.
Changing science to become more equitable requires an enormous shift in the way science operates. But, in this case, what’s good for women and people with menstrual cycles happens to also be good for science. An inclusive scientific paradigm and practice will start to build a bigger, more comprehensive, and more detailed picture of evidence — leading to healthier brains and lives for everybody.