Marian Diamond, a neuroscientist, gave new meaning to ‘use it or lose it’
She died at 90 years old
Adapted from a story by The Washington Post’s Harrison Smith.
In papers and lectures, pathbreaking neuroscientist Marian Diamond outlined five factors crucial to brain development at any age: diet, exercise, challenge, newness and — perhaps surprising for a laboratory researcher — love.
She said she stumbled upon the fifth factor while performing experiments with lab rats. The rats weren’t living long enough for her to study their brains in old age. Although the cages were well cleaned, many of the rats were dying after about 600 days, or roughly 60 years in a human time span. But some were living much longer.
The difference, Diamond found, was touch. By holding the lab rats against her lab coat and petting them each day, she found that she could increase their life span — and found that these rats generally had thicker cerebral cortices.
This is just one of the groundbreaking discoveries Diamond made before she died on July 25 at age 90 at an assisted living facility in Oakland, Calif. She was considered a foundational figure in modern neuroscience, and she spent a half century teaching at the University of California Berkeley. Her lectures will live on: Diamond was one of the most popular professors on YouTube, where videos of her anatomy course were viewed more than 1 million times.
Diamond considered the brain to be “the most complex mass of protoplasm on this earth and, perhaps, in our galaxy,” and she spent her life studying it.
In the early 1960s, Diamond found that when rats were raised alone in small and desolate cages, they had more trouble navigating a maze than rats that were raised in “enriched” cages, with toys and rat playmates.
Studying their brains under a microscope, Diamond found that the cerebral cortices of the rats in enriched cages were about 6 percent thicker than the rats in the “impoverished” cages.
Her findings, published in a 1964 paper with three colleagues, were a pivotal contribution to the long-running debate between nature and nurture, which seeks to determine the extent to which a person is shaped by their genes or by their life experiences.
At the time, genes were believed to play the all-important role.
“The idea that the brain could change based on environmental input and stimulation was felt to be silly,” said Robert Knight, a UC-Berkeley professor of psychology and neuroscience. “And that’s the boat she completely sunk.”
Diamond went on to develop a rich theory of brain plasticity, one that she sometimes summarized with a phrase more commonly heard at a gym than a neuroscience classroom: “Use it or lose it.”
She made headlines in the 1980s for performing research on Albert Einstein’s brain. After the physicist’s death in 1955, his brain was removed and preserved — without permission from Einstein’s family — by pathologist Thomas Harvey.
Decades later, Diamond asked to study several sections of Einstein’s brain. In 1984, three years after making her request, the brain finally arrived in the mail: four thin slices, preserved in formaldehyde and stored inside a mayonnaise jar.
Placing the tissue under a microscope, Dr. Diamond found an unusually high amount of glial cells, which were thought to be a relatively unimportant part of the tissue that held the brain together. Her discovery launched renewed interest in the role of glial cells, which are now believed to play a crucial role in cognitive processes.
Diamond faced gender discrimination early on, according to Gary Weimberg, who co-directed a 2016 documentary, “My Love Affair with the Brain.” In one of her first major articles, she told him, a male colleague failed to properly credit her contributions. Although she performed the bulk of the research and initiated the project, her name was the last of four and — as though it were incidental — was listed in parentheses.
Diamond said she confronted the colleague, who told her that he had never written an article with a female co-writer. “Treat it like another name,” she said. Ultimately, her name appeared first.
