Thomas Michael Jessell was a pioneering developmental neuroscientist and the Claire Tow Professor of Neuroscience and Biochemistry & Molecular Biophysics at Columbia University. Born in London in 1951, he received his first-class honors degree in pharmacology from Chelsea College, University of London, and earned his PhD from Cambridge University before completing postdoctoral training at Harvard Medical School with Gerald Fischbach. He joined Harvard's faculty in 1981 and moved to Columbia University in 1985 as a Howard Hughes Medical Institute Investigator, where he established himself as a transformative figure in neural development research. Jessell held significant leadership roles as Co-Director of both the Mortimer B. Zuckerman Mind Brain Behavior Institute and the Kavli Institute for Brain Science at Columbia until 2018. His distinguished career was tragically cut short when he passed away on April 28, 2019 from progressive supranuclear palsy.
Jessell revolutionized developmental neuroscience by transforming it from a descriptive field to a mechanistic and molecular science, with his primary focus on understanding how nerve cells in the developing spinal cord assemble into functional circuits that control sensory perception and motor actions. His groundbreaking 1994 discovery that netrin guides commissural axons in the vertebrate spinal cord provided fundamental insights into neural circuit formation during embryonic development. The principles emerging from his spinal cord studies proved applicable throughout the central nervous system, establishing a basic ground plan for understanding brain development and the molecular basis of neural identity. His work on transcriptional control of neural identity demonstrated the conversion of embryonic stem cells into specific neuronal types, offering potential therapeutic approaches for diseases like amyotrophic lateral sclerosis. These discoveries have profoundly influenced our understanding of neurological disorders including autism and schizophrenia by providing molecular explanations for cortical specialization.
Throughout his career, Jessell received numerous prestigious awards including the Kavli Prize in Neuroscience, the Gruber Foundation Neuroscience Prize, the Vilcek Prize in Biomedical Science, and the Gairdner International Award, recognizing his transformative contributions to the field. He was a dedicated educator who directed the research of 13 graduate students, 48 postdoctoral fellows, and 3 sabbatical visitors, while also co-authoring influential neuroscience textbooks including Principles of Neuroscience and Principles of Development. Jessell's leadership extended to serving on numerous editorial boards and advisory committees across major neuroscience institutions, where he helped shape the direction of neuroscience research globally. Although Columbia University closed his laboratory in 2018 following an internal investigation, his scientific legacy continues to guide contemporary research in neural development and circuit formation, with his foundational principles remaining central to understanding both normal brain function and neurological disorders.
