Research on rats shows significant differences in brain anatomy between men and women. But that research could be under threat. (Image credit: Photo illustration by Marilyn Perkins; Image via Martin Barro via Getty Images)
The Trump administration's actions have catalyzed changes at key U.S. scientific institutions that, at worst, could threaten our understanding of how the brain works and how to treat neurological disorders, experts told Live Science.
For many years, the National Institutes of Health (NIH) has had a policy requiring researchers working with vertebrates to consider “sex as a biological variable.” To receive grants, scientists must explain how their research plans take sex into account so that any sex differences are clearly represented. Researchers must provide a compelling scientific justification for including only one sex in a study.
But The Transmitter recently reported that the NIH appears to have suspended the policy. The NIH has yet to issue an official statement on the matter, but the move follows Trump administration orders calling for the repeal of “gender ideology” and “radical” diversity, equity, and inclusion programs.
It seems that suspending the “sex as a biological variable” policy may mean abandoning the requirement to include both men and women in research. And such a shift could have a particularly negative impact on basic research in neuroscience.
New animal research reveals significant differences between the male and female brains in how sex hormones affect the brain in terms of memory formation and neural activity, and the data suggest that these differences may be relevant not only to lab animals but to humans as well. Excluding both sexes from lab studies may mean we miss key mechanisms that shape the human brain and its response to drugs.
“If the underlying mechanisms by which molecules influence neurophysiology differ between the sexes, we need to know about it sooner rather than later,” said Katherine Woolley, a professor of neuroscience in Northwestern University's Weinberg College of Arts and Sciences.
A Lasting Legacy of Bias
Are there differences in the structure of the brains of men and women? This question has troubled humanity for centuries, but scientists have only recently begun to find answers to it.
This is partly because identifying differences between males and females requires studying both sexes, including lab animals. But scientists haven't done this until relatively recently.
Animal research allows experiments that are impossible to perform on humans. Researchers cannot cut open the heads of living people, extract their neurons, or insert electrodes with the same intensity.
Human subjects also have their own experiences: men and women are raised differently and have different life circumstances. These cultural factors influence brain development along with biological aspects such as hormones and chromosomes, making it difficult to separate the influence of nature and nurture.
Yet scientists have historically ignored gender as a variable, excluding women entirely. This bias has been particularly pronounced in neuroscience: One 2009 review found that studies conducted exclusively on male lab animals outnumbered those on females by 5.5 to 1.
There was a concern that the reproductive cycle of female lab animals would “confound the data, make it too variable,” said Liz Elliott, a professor of neuroscience at the Rosalind Franklin University of Medicine and Science in Chicago. That idea has been thoroughly debunked, but for a while the prevailing wisdom was, “Let’s just study males and keep it simple,” Elliott told Live Science.
Only in recent years has this attitude begun to change.
Inclusive research generates discoveries
The inclusion of female laboratory animals in the studies led to a discovery that overturned long-held
Sourse: www.livescience.com
