obituary In memory of Bruce McEwen: a gentle giant of On 2 January 2020, the neuroscience community lost not only a pioneering fgure, but also a generous and infuential thought leader. Bruce Sherman McEwen, head of the Harold and Margaret Milliken Hatch Laboratory of at the , passed away at age 81, following a short illness. A member of the National Academy of Sciences, National Academy of Medicine and American Academy of Arts & Sciences, and former president of the , Bruce will be remembered for his profound scientifc impact, measured not only by output of papers, but also by the large family of neuroscientists he trained over a career spanning nearly six decades. Above all, Bruce will be remembered for his generosity, kindness, gentleness of soul, and for being an extraordinary mentor.

orn 17 January 1938, Bruce obtained by which we understand how adverse life a Bachelor’s of Science in chemistry events impact physical and . Bfrom , followed by In addition to his work on , Bruce a PhD in cell biology from Rockefeller was a pioneer in understanding how gonadal University in 1964. Following a short steroids act in the brain. His early work time in Sweden furthering his training, helped to map brain estrogen receptors, Bruce returned to the US and founded and his lab discovered that reproductive the Laboratory of Neuroendocrinology in hormones could influence structural 1966. From his first paper in 1959 to the plasticity of dendrites and synapses. time of his death, Bruce published over Bruce’s work in this area contributed to 1,000 scientific articles (with over 130,000 the understanding of sex differences and citations) on topics ranging from molecular was foundational for the now-widespread mechanisms of steroid action in the brain to recognition of the need to consider sex as the health impacts of early-life adversity. The a biological variable in neuroscience and breadth of his work and interests led Bruce beyond. to describe himself later in his career as a In both his personal and professional life, “molecular sociologist.” Bruce was a family man. He was an adoring While the effect of stress hormones husband, father and grandfather. Bruce’s on the brain is taken for granted now, it scientific family came to lovingly refer to was Bruce’s 1968 paper in Nature that first each other as the ‘McEwenites’, brought demonstrated receptors for the adrenal together across generations and research stress steroid, corticosterone, in the fields by Bruce’s generous mentorship. Bruce hippocampus. This seminal finding led to frequently adopted neuroscientists from recognition that steroid hormones have a outside his lab into this scientific family, direct impact on neural function. Over the treating all to his scientific and personal Credit: Tiffany Lee subsequent five decades, Bruce continued generosity. Without regard for his own to lead the field in understanding the professional stature, Bruce never viewed his neurobiology of stress. Work by his lab, and trainees as competition, instead supporting by his myriad of trainees, revealed neural decline. Work from Bruce’s lab also set the everyone to take their ideas and flourish and plasticity influenced by stressful experience stage for how we now understand stress to go on to do great things independently. It and created a template for understanding be a contributing factor in the development is rare to find an individual who can claim how these alterations could influence of chronic inflammatory and metabolic such a long and wide lineage of successful behavior, from affect to cognition. His diseases. This aspect of Bruce’s work scientific offspring. work showing stress-induced structural highlighted reciprocal relationships between While this obituary might attempt plasticity of dendrites and regulation of the brain and body as being critical to both to spell out a small fraction of his neurogenesis in the hippocampus susceptibility and resilience to stress. achievements, Bruce rarely, if ever, revealed mechanisms by which stress Bruce was a key figure in developing discussed his own accomplishments, exposure remodels corticolimbic circuits the concept of ‘allostatic load’, which posits legacy or impact in science. Bruce did what and influences susceptibility to psychiatric that physiological adaptation to persistent he did for the generation of knowledge illnesses. Bruce also studied how stress at or repeated challenges imparts a cost in the and the advancement of society, not for different life stages could have different form of cumulative wear and tear on the accolades. He had an infectious energy and effects, with early-life stress leaving a body. This conceptualization of the health optimism. Whether it came in an hours- lasting impact on the developing brain, impacts of stress had an unquestionable long discussion about a finding in the lab while aging increased vulnerability to impact on the field of stress biology and still or a comprehensive review article, Bruce stress, contributing to accelerated cognitive represents the primary theoretical model appreciated any advance and celebrated

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every success. He was patient and generous scientific discovery. Bruce’s goal was to bring 1Departments of Cell Biology and Anatomy, and gave his time and energy to everyone humanity into science and use knowledge, Mathison Centre for Mental Health Research and and anyone. One was just as likely to and compassion, to improve the human Education, Hotchkiss Brain Institute, University of see him talking to an undergraduate condition. We, as authors, are a few of Calgary, Calgary, Alberta, Canada. 2Department student at their poster as to see him rubbing the fortunate group of scientists who had of Psychological and Brain Sciences and Center for shoulders with Nobel laureates or celebrities. the privilege to have trained with and Neuroendocrine Studies, University of Massachusetts In his actions, Bruce reminded us that, learned from Bruce and to be directly Amherst, Amherst, MA, USA. 3Department of ultimately, we are all the same and it is by influenced by his intellect, generosity and , Leiden University Medical Center, working together that we can achieve great optimism. However, we all, scientists and Leiden, Te Netherlands. 4Centre for Studies on things in science. non-scientists alike, would benefit from Human Stress, Institut Universitaire en Santé Bruce McEwen’s passing will have a adopting the gentle demeanor, modesty Mentale de Montréal, Montreal, Québec, Canada. resounding impact on the neuroscience and generosity that Bruce exhibited to 5Department of Neurobiology, Northwestern community and will not be easy to recover everyone he met. ❐ University, Evanston, IL, USA. from. His legacy will be carried on by the ✉e-mail: [email protected] hundreds of McEwenites and the thousands Matthew N. Hill1 ✉ , Ilia N. Karatsoreos 2, more influenced by his work who will E. Ron de Kloet3, Sonia Lupien4 and Published online: 23 March 2020 continue to advance knowledge and Catherine S. Woolley5 https://doi.org/10.1038/s41593-020-0613-y

474 Nature Neuroscience | VOL 23 | April 2020 | 473–474 | www.nature.com/natureneuroscience