On January 8, 2025, the ACNP lost one of its guiding lights, Floyd E. Bloom, M.D. Floyd helped establish neuroscience as a multidisciplinary field and was instrumental in guiding our College to bridge basic neuroscience with clinical need and application. Floyd was accepted into the College in 1968, on numerous ACNP Committees over the years, a member of the Council (1976–1978), President (1989), and eventually a Fellow Emeritus. He was also President of the Society for Neuroscience (1976–1977), Editor in Chief of Science (1995–2000), President of the American Association for the Advancement of Science (2002–2003), and an ambassador for neuroscience to the broader science community.

Credit: Stephanie Aston-Jones

Floyd graduated from the Washington University School of Medicine in 1960. After an internship and residency, during which he picked up his signature habit of wearing a bow tie to avoid the obstruction of a longer tie during blood draws, he became a Research Associate at the NIMH facility at St. Elizabeths Hospital. In those two years, he launched his research career using the electrophysiological technique of microiontophoresis. He then moved to Yale as a postdoctoral fellow and then Assistant and Associate Professor. Working with another ACNP luminary, George Aghajanian, Floyd developed expertise in electron microscopy and characterized neurotransmitter-specific presynaptic processes. During this time he also co-authored, with Jack Cooper and Bob Roth, the “bible” of neuropharmacology, The Biochemical Basis of Neuropharmacology.

In 1968, Floyd returned to become Chief of the Lab of Neuropharmacology at NIMH, St. Elizabeths. He began the (at the time) novel multidisciplinary approach of combining anatomical, physiological, and pharmacological tools to characterize the functioning of noradrenergic brain synapses, a question that motivated him throughout his career. In 1971, he, Barry Hoffer, and George Siggins published a tryptic of articles documenting the anatomy, electrophysiology, and second messenger impact of noradrenergic synapses originating from the locus coeruleus onto cerebellar Purkinje cells. This new paradigm pointed the way for future studies demonstrating functions for clinically important brain pathways.

Floyd moved to the Salk Institute in 1975 to develop the Arthur Vining Davis Center for Behavioral Neurobiology. This lab became a Mecca for multidisciplinary neuroscientists with frequent visits by Les and Susan Iversen, Harvey Karten, Roy Wise, Kjell Fuxe, Barry Everitt, Alim (Ben) Benabid, and many others. Floyd collaborated with the neighboring lab of Roger Guillemin to establish a neurotransmitter role for the (new at that time) endogenous opioid, beta-endorphin. Here, Floyd also began his seminal studies using subtractive RNA hybridization, by which his team (working with Greg Sutcliffe and others at Scripps) later identified the novel hypothalamic neuropeptide hypocretin (orexin). Shortly after his arrival at the Salk, Floyd was elected to the National Academy of Sciences, becoming one of its youngest members at 40 years of age.

In 1983, Floyd and his team moved to the Scripps Research Institute a few blocks away. The expansion of space allowed for major advances in 3-D quantitative microscopy, more extensive nonhuman primate models, discovery of region-specific gene expression patterns and novel neuropeptides, neurotransmitter-based neurophysiology, neurovirology, AIDS research, and a dramatic expansion of behavioral pharmacology. The Scripps years also saw a significant expansion of translational research, reflecting the maturation of neuroscience and collaborations with clinical colleagues at Scripps. Floyd further developed his interest in applying basic neuroscience to clinical disorders by launching a biotech company, Neurome, dedicated to the characterization of the earliest pathologic events in human disease.

Floyd won numerous awards throughout his career, including the Paul Hoch Distinguished Service Award from the ACNP in 1998, as well as the Walsh McDermott Medal, the Janssen Award in the Basic Sciences, the Pasarow Award in Neuropsychiatry, the Hermann van Helmholtz Award, and the Sarnat Award for Mental Health Research. He also was a member of the Royal Swedish Academy of Sciences and the Institute of Medicine (now the National Academy of Medicine) and received numerous honorary degrees from major universities.

Floyd was a dedicated proponent for science overall (as evidenced by his role as Editor in Chief of Science magazine). He cared deeply about the future of science, both in terms of funding and ability to attract trainees (as described in his Past-President’s lecture at ACNP of 1990). Floyd had a profound and far-reaching role as a mentor. Being part of the “Bloomlab” was a great source of pride to those fortunate enough to be directly within his orbit. This relationship was reflected in the Bloom Family Tree that his prior trainees assembled in 2005 for a special ceremony. Twenty years ago, the Bloom Family Tree extended across four generations including 1000 neuroscientists spread across 60 sites in the United States, 17 in Canada, 1 in Mexico, and 45 sites in 15 countries across Europe and Asia. One memorable epithet Floyd provided to his trainees (which accompanied a photo of him finishing the Honolulu Marathon) was “In the marathon of life there is no finish line”. In 2025, members of his Family Tree continue Floyd’s marathon to carry on his commitment to scientific discovery, integrity, honesty, and generosity.

For more color and interesting details on Floyd’s life, we refer the reader to his autobiography in Larry Squire’s excellent book “The History of Neuroscience in Autobiography: Volume 7” (Oxford University Press, 2011). See also a recent article on his life in Science magazine (Leshner AI, Thorp HH (2025) Citizen of science. Science 387:345–345) and in The Transmitter (https://doi.org/10.53053/XOWO2022).