Women’s History Month is a great time to highlight transformative female scientists. My focus this year is neuroscientists, and I was overwhelmed by the deep roster. Due to space limitations, I profile only two scientists. Still, many deserve a shoutout for dramatically advancing the field of neurosciences.
Marian Diamond
Imagine a professor walking on campus, carrying a flowered hat box. If it was in the 1960s, and you were at the University of California at Berkeley, you were seeing Professor Marian Diamond, who taught integrative biology, a field she founded that explores the interrelationships between organisms and our physical and biological environment. Inside her hat box would be a preserved brain for lecture purposes. Her passion for teaching helped spawn a generation of biologists.
Diamond’s research focused on the influence environmental factors play on brain development. She ran controlled experiments with rats who shared a cage filled with toys, compared to isolated rats without toys. On the 80th day, she measured their brains’ anatomy and found a 6 percent difference in the cerebral cortex between the two groups.
She repeated the experiment at her colleagues’ behest, for longer (904 days). Daily, she would pet one group but not the other. Again, she found that nurtured rats had a thicker cerebral cortex and increased lifespan. While the mammalian brain is considered a fixed and immutable macrostructure, its cerebral cortex is different, with a flexible microarchitecture that responds to its environment.
This discovery of the changing cerebral cortex opened the doors for what is now understood as the brain’s plasticity. Neurons can be developed at any age by stimulation. Diamond, who coined the expression “use it or lose it,” identified five essential factors to stimulate the brain: good diet, exercise, challenges, newness and love.
Diamond again showed the importance of brain anatomy in studying Einstein’s brain. By analyzing a preserved slice, she discovered that Einstein had more glial cells than neurons in a region responsible for synthesizing information. This was significant because glial cells make one smarter and suggested that anatomical differences accounted for Einstein’s genius.
Diamond’s work laid the foundation for understanding how we nurture children and how our behavior affects brain development and preservation.
Rita Levi-Montalcini
Rita Levi-Montalcini achieved fame in 1986, sharing the Noble Prize in Physiology and Medicine with Stanley Cohen for identifying the role of the Nerve Growth Factor (NGF) in spurring tumor growth. Emerging as a scientist during World War II, Levi-Montalcini’s single-minded purpose and ability to overcome obstacles were equally impressive.
Born in 1909 in Turin, Italy, Levi-Montalcini grew up in a traditional Jewish family where she was expected to be a wife and mother. She saw it differently and persuaded her parents to let her study. After observing a family friend die of stomach cancer, Levi-Montalcini decided to pursue medicine. She graduated from Turin Medical School with the highest honors in 1936. While at Turin, Levi-Montalcini and two medical school colleagues studied under Italian histologist Giuseppe Levi, and all three won a Nobel Prize, though separated by years.
Levi-Montalcini was to pursue a program in neurology and psychiatry, but when Mussolini barred Jews from academic and professional careers, Levi-Montalcini set up a research shop at home. Her mentor, Giuseppe Levi, who had escaped the Nazi invasion of Belgium, joined her home lab. Upon reading Viktor Hamburger’s article on the effects of limb removal in chick embryos, Levi-Montalcini found her focus and began work, discovering that nerve cells die when they lack targets. This laid the foundation for her most important research identifying Nerve Growth Factor (NGF).
When Germany invaded Italy in 1942, Levi-Montalcini fled to Florence, where she lived underground and was a medical doctor for war refugees. Only when the war ended could Levi-Montalcini resume her research.
She accepted an invitation in 1946 from Viktor Hamburger to join his team at Washington University. She repeated her experiments, isolating NGF from certain cancerous tissues experiencing extremely rapid growth of nerve cells.
Levi-Montalcini identified NGF as belonging to a group of molecules responsible for developing neurons that also perform maintenance and repair. The discovery of NGF helped pave the way for modern cell biology.
Two pioneers, Marion Diamond and Rita Levi-Montalcini, furthered our understanding of the brain’s plasticity and mechanisms for neuron growth, laying the necessary groundwork for scientists who followed.
