A leading figure in the field of neuroscience, Bruce McEwen, died on January 2 after a brief illness.

Beginning in the 1960s, explored how stress hormones could alter the way genes are expressed in the brain, having a consequent impact on memory, mood and decision-making. This work contradicted the accepted academic dogma of the time that the brain does not change during adulthood.

One noted example of the Rockefeller University professor’s work was the finding that chronic stress could lead to loss of neurons in the brain’s hippocampal area, a locus for memory formation.

McEwen, 81, head of Rockefeller’s Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, worked with his wife Karen Bulloch, also a Rockefeller professor, to examine brain immune cells in inflammation and neurodegenerative disease.

In 1976 he wrote an article for Scientific American entitled “Interactions between Hormones and Nerve Tissue,” in which he observed, in the formal language of the day:

In our laboratory at Rockefeller University we have located various hormone-sensitive brain cells and have undertaken to establish how they fit into the nerve pathways that govern behavior and regulate the hormone-producing glands. Here I shall discuss our findings and also describe how the steroid products of the testes participate in the sexual differentia­tion of the developing brain.

During his career, he coined the term “allostatic load” to convey how lingering stress affects body and brain—and much of his recent research was devoted to the impact on the brain of nutrition, physical activity, early-life trauma and other factors.

One of McEwen’s well-known former graduate students, Robert Sapolsky, remarked in a prepared statement from Rockefeller: “His work became increasingly more expansive and integrative—in later years he called himself a ‘molecular sociologist.’ He made the most seminal findings regarding how steroid hormones affect the brain.” Sapolsky is a professor of biological sciences at Stanford University.

McEwen’s research has been cited more than 130,000 times in the scientific literature, and he was co-author of The End of Stress as We Know It (Joseph Henry Press, 2002).