How did I ever know I could teach! The first time a medical student asked me a question and I knew the answer, I felt a deep, warm glow of satisfaction radiate through my body. This is where I belong.

Marian Diamond

Transverse section through the somatosensory cortex of a rat brain to measure the cortical depth. © MC. The effects of an enriched environment on the histology of the rat cerebral cortex. J Comp Neurol. 1964.

Marian Diamond, a founder of modern neuroscience, was born in Glendale, Califor-nia in 1926. She earned a degree in biology in 1948 and a master’s degree in anatomy in 1949 at University of California, Berkeley. In 1953, she received her doctorate with a dissertation on the hypothalamus. She married Richard M. Diamond in 1950 and the couple had four children. After researching at Harvard University for two  years and teaching at Cornell University from 1955–1958, she returned to U.C.  Berkeley as a lecturer and researcher. In 1964 she began studying the brains of lab rats and found that they exhibited structural changes depending on their envi-ronment. This demonstrated the plasticity of the brain for the first time, overturning the long-held belief that the adult brain is a genetically predetermined, immutable organ. Diamond had to patiently defend these groundbreaking find-ings showing that brains continue to develop at any age. In 1984 she studied preserved tissue from the brain of Albert Einstein, finding more support cells than in the average brain. She also published research into the link between positive think-ing and immune health and into the differences between female and male cerebral cortexes. Marian Diamond retired in 2014 after 60 years of research and teaching, and died in 2017 at the age of 91.