Diamond, with her signature hatbox, in which she carried a preserved human brain.

Marian Cleeves Diamond, a revolutionary neuroscientist best known for studying Albert Einstein’s brain and publishing research that showed environmental factors can change the human brain, died July 25 in her Oakland, Calif. home. She was 90-years-old.

Diamond’s career at the University of California, Berkeley as a researcher and Professor Emerita of Integrative Biology spanned half a century.

She gained “celebrity” status in 1984, when she studied four preserved slices of Albert Einstein’s brain and found that he had more support cells in his brain than the average brain.

But she conducted a lifetime of groundbreaking research that led to her being known as a founder of modern neuroscience.

One of the most notable examples was with her work in rats, in which she discovered that an enriched environment--in the case of the rat research included toys and companions--changed the anatomy of the brain. Her studies led to the conclusion that an enriched and stimulating environment could benefit the brain of any animal, including humans, and that an environment lacking enrichment could result in a lower capacity to learn.

She used the findings to develop educational programs in science and mathematics for students in preschool through high school, according to UC Berkeley.

“Her research demonstrated the impact of enrichment on brain development--a simple but powerful new understanding that has literally changed the world, from how we think about ourselves to how we raise our children,” said UC Berkeley colleague George Brooks, a professor of integrative biology. “Dr. Diamond showed anatomically, for the first time, what we now call plasticity of the brain.”

She contributed to other major findings, including that the brain can keep developing throughout a person’s lifetime, that male and female brains are structured differently, and that stimulating the brain can enhance an individual’s immune system.

Diamond was born Nov. 11, 1926 in Glendale, Calif., and was the youngest of six children. Her father, Montague Cleeves, was an immigrant from northern England, and her mother, Rosa Marian Wamphler, was a UC Berkeley graduate who cut her Ph.D. studies short to raise her family.

Marian transferred from Glendale Community College to UC Berkeley in 1946. Two years later, she obtained a bachelor’s degree and became the first female graduate student in the university’s Department of Anatomy.

From 1952 to 1953, she worked as a research assistant at Harvard University. In 1955, she was appointed as the first woman science instructor at Cornell University, where she taught human biology and comparative anatomy.

Diamond returned to UC Berkeley in 1960, and just four years later she had the first actual evidence--in the form of anatomical measurements--"showing the plasticity of the anatomy of the mammalian cerebral cortex."

However, her work was met with resistance from some fellow neuroscientists. In a book she co-authored, titled “Magic Trees of the Mind: How to Nurture your Child’s Intelligence, Creativity, and Healthy Emotions from Birth through Adolescence,” Diamond recalled a man who stood up after a lecture she gave at a scientific conference and shouted, “Young lady, that brain cannot change!”

"But I felt good about the work, and I simply replied, 'I'm sorry, sir, but we have the initial experiment and the replication experiment that shows it can,'" she wrote.

Her passion for neuroscience was clearly evident, and infectious. According to an obituary from UC Berkeley, Diamond frequently brought a floral hatbox containing a preserved brain to her classes. She would carefully hold up the brain in front of her students and comment on how incredible it was that a small, 3-pound mass of protoplasm was the most complex structure known to humankind.

YouTube videos of her lectures have received more than 1 million views.

Diamond was a living example of the findings of her enrichment research. To start her workdays, Diamond would swim laps at the Berkeley campus before attending classes or conducting research. She taught and did research until 2014, when she tired at the age of 87.

Among her last words were, “If you’re going to live life, you’ve got to be all in.”

Diamond was a fellow of the American Association for the Advancement of Science, a California Professor of the Year and National Gold Medalist from the Council for Advancement & Support of Education, a UC Berkeley Alumna of the Year, recipient of the 2012 Clark Kerr Award for Distinguished Leadership in Higher Education and a 1975 Distinguished Teaching Award recipient from UC Berkeley.

She was also the focus of a 2016 documentary film, My Love Affair with the Brain: The Life and Science of Dr. Marian Diamond, by Catherine Ryan and Gary Weimberg.

“Marian Diamond (will be) remembered as an esteemed colleague, a friend and a gentle soul who by nature and nurture sought to extend happiness and accomplishment to her students, colleagues and others,” said Brooks.

A 2010 image of Marian Cleeves Diamond with a preserved human brain. Photo: Elena Zhukova/UC Berkeley