What does science owe to Marian Diamond, the woman who dissected Einstein’s brain?

Marian Diamond was born on November 11, 1926 in Glendale, California. She is the daughter of Rosa Marian Whampler, a Latin teacher at Berkeley High School, and Dr. Montague Cleeves, a physician at Los Angeles County Hospital. At the age of 15, while following her father through the corridors of the hospital where he works, she sees through the crack of a gate a scene that will determine the rest of his life. Four men stand around a table on which a jar containing a brain has been laid.

She doesn’t know what they are doing, but her attention is focused on the inert organ that rests in its liquid. Is that where all our thoughts come from? Of this little edifice of cells, capable of being held in one hand? Marian is overwhelmed by the complexity and mystery of this brain human, whom she meets for the very first time. It’s the beginning of a love story that will only end with his last breath.

Marian joined the University of Berkeley where she obtained her degree in biology at the age of 21, then spent a summer at the University of Oslo. Back to his alma mater, she is working on her doctoral thesis and at the same time begins to teach, a passion that will never leave her. In 1953, she became the first woman to graduate fromanatomy in the history of the university, the triumphant survivor of a promotion counting an overwhelming majority of 100 men for 5 women. Now officially a doctor in human anatomy, Marian now hopes to be able to devote herself entirely to the study of the human brain. But his disillusion is bitter. Marian does not let herself be dismantled.

Genesis of a new discipline

Towards the end of the 1950s, she discovers an experience that will give her an idea. In this study, researchers analyzed the brains of rats that had learned to move through mazes and revealed that levels of acetylcholinesterase, a chemical messenger that allows communication between neurons, are much higher there than in the brains of control rats. The result is surprising, but it does not go far enough for the anatomist.

At the time, the predominant idea was that the brain is an organ whose structure is genetically predetermined and immutable once you reach adulthood. But another conviction gradually takes hold of Marian. What if our brain changes throughout our lives, based on our experiences and interactions?

To find out for sure, she contacted one of the authors of the study, psychologist Mark Rosenzweig, and asked to join his team, made up of another psychologist, David Krech, and chemist Edward Bennett. In just a few years, the four researchers set up a pioneering experiment that will open up a new field of neurology.

How to prove the plasticity of the brain?

In order to assess the impact of the environment on the anatomy of the brain, they created three groups of male rats from the same line, thus limiting the risks of variation genetic. A first is placed in so-called enriched cages, where the rodents can interact with each other and have ladders to explore and wheels to practice on; a second is placed in an impoverished environment where the rat is alone in a bare cage; and finally, a third serves as a control group, where the rats are placed together, without toys to stimulate them.

After 80 days, the brains of the rats are dissected, cut into very thin strips and analyzed with microscope. The result is clear: the cortex rats from the enriched condition is 6% thicker than that of rodents reared in depleted cages, and their ratio of glial cells per neuron is more important. Marian and her colleagues have just demonstrated for the very first time the existence of what we now call neuroplasticityand to highlight the hitherto unsuspected importance of glial cells in thelearning. After several replicationsthe study was finally published in the journal Science.

What was Marian Diamond carrying in her hatbox?

Marian must still come up against a lot of prejudice, especially now that the publication of her study has shaken up the beliefs of the time about the immutability of the brain, but she continues to defend her work with patience and objectivity. A teacher adored by her students, we regularly see her going to or returning from amphitheaters with a hatbox in her hand. She hides inside an authentic brain that she likes to present to her students at the beginning of the year.

In 1984, Marian’s Berkeley office became the refuge of another container with unusual contents: the jar of mayonnaise sent by Thomas Harvey, containing 4 fragments of Albert’s brain Einstein.

The circumstances of obtaining this strange relic are controversial to say the least. After all, the instructions left by the famous scientist when he died were crystal clear: burn my body and scatter my ashes in secret because I do not wish to be idolized.

Disobedience that sheds light on science

But Thomas Harvey, in charge of theautopsy of the deceased physicist, does not intend to respect these wishes. He extracts everything he can from the body entrusted to him, including its internal organs, its eyes, which he sends to Einstein’s ophthalmologist and his brain which he keeps at home; then he sends the remains to the services in charge of his cremation. The theft is quickly noticed, however, and the Princeton hospital immediately fires Harvey.

Einstein’s family for their part point the finger at the sacrilegious act committed by the pathologist, and only reluctantly does the scientist’s son finally allow Harvey to keep the brain. This one hastens to cut it into 240 small pieces which he preserves in celloidine, and apart from a few shipments to scientists around the world, the debited brain of Albert Einstein ends up resting for 40 years in various jars and boxes, gathering dust in Harvey’s basement.

What does the dissection of Einstein’s brain reveal?

Fortunately, Marian does not intend to leave these pieces of pinkish flesh in their jar. The method of preservation used by Harvey is exactly what he needs: it will be able, as with the brain rats, cut the physicist’s cortex into thin slices and observe in detail the distribution of the cells that make it up. She focuses her attention on the prefrontal cortex superior and inferior parietal of the left and right hemispheres and then compares the results with identical regions taken from 11 male human brains.

Conclusion: area 39, known as Brodmann’s area, has a greater number of glial cells in the scientist, more specifically astrocytesresponsible for supplying and repairing neurons, and oligodendrocytes, which participate in their proper communication.

The study is the first to look at Einstein’s brain, but its results will remain controversial, as will those of the studies that will follow. It is difficult to interpret with certainty the analyzes carried out on a brain that has been dead for almost 30 years, and to find other brains of relatively similar age and health with which to compare it.

Although today the general public remembers Marian Diamond as the woman who dissected Einstein’s brain, it was her experiment with rats that elevated her to the rank of the great scientists of the last century. Marian continued to teach at Berkeley until the age of 80 and even became a star on youtube, where its courses are broadcast by the university. She passed away on July 25, 2017, at the age of 90. History does not tell us if his brain was bequeathed to science.