Thomas Jessell grew up in the post-war London of the 1950s and 1960s. When it was time to go off to college in 1969, Jessell was undecided about the choice of career - Jessell’s grandfather had been a distinguished organic chemist, but he was also drawn to the visual arts, an interest instilled in him by his mother, who worked as a paintings conservator.
A few weeks into life at Chelsea College in the University of London, Jessell sat in on a series of lectures by the neuropharmacologist John Bevan. “He introduced me to the world of drug actions on the nervous system,” Jessell recalls. “And I became fascinated with the organization and function of the nervous system from that point on.”
Jessell received an undergraduate degree in pharmacology from the University of London in 1973, and then a PhD in neurochemical pharmacology from Cambridge University in 1977. He spent a short period in Tokyo, investigating the role performed by neuropeptides in transmitting pain and other messages within the central nervous system (CNS). In 1978, Jessell took a post-doctoral position in the neuroscience lab of Gerald Fischbach at Harvard University, where he focused on the development of synaptic connections between neurons and muscle cells. In 1981, he became an assistant professor of neurobiology at Harvard and launched his own research lab.
“Around that time the impact of the molecular biology revolution was becoming ever more apparent, and it became clear that to intervene in complex aspects of circuitry and behavior one was going to have to absorb molecular insights,” Jessell recalls. Columbia University had recently launched a highly innovative center for such molecular approaches, so, in 1985, Jessell decided to move to New York. He has remained at Columbia University ever since, and is now its Claire Tow professor in the departments of Neuroscience and Biochemistry & Molecular Biophysics. He also currently serves as co-director of the university’s Mortimer B. Zuckerman Mind Brain Behavior Institute.
While at Columbia, Jessell has focused his research on the neural circuits that control movement, becoming one of the world’s leaders in the fields of developmental neuroscience and motor control. Through a groundbreaking series of studies, he has identified many of the key cellular, molecular, and genetic mechanisms that control the neural development and organization of the spinal cord. He was the first to show, for example, that the Sonic hedgehog (Shh) protein is a morphogen, or signaling molecule, and determines the “fate” of motor neurons—their subtype identify and their role in movement—early in embryonic development. He has also been a pioneer in demonstrating how the Shh and other signaling pathways can be manipulated to direct the process by which stem cells mature into motor neurons—research that has provided new insights into how stem cells might be used to treat degenerative spinal cord diseases, including amyotrophic lateral sclerosis (ALS).
The implications of Jessell’s discoveries extend beyond the spinal cord, however. By establishing the spinal cord as a model system for studying neural development, he has helped scientists achieve a better understanding of the neural circuitry of other, more complex areas of the CNS. Indeed, the ability to convert stem cells into specific subtypes of neurons has widespread potential for applications in clinical neuroscience.
Jessell has received numerous honors and awards during his career, including memberships in the Institute of Medicine and the National Academy of Sciences in the United States and in The Royal Society and the Academy of Medical Sciences in his native Great Britain. He has also mentored and trained many graduate and postdoctoral students who are now recognized leaders in neural developmental research at academic institutions around the world. In addition, Jessell is the co-author of one of the field’s classic textbooks, “Principles of Neural Science,” which is now in its fifth printing.
Jessell lives in New York City which, he says, has been wonderful for nurturing not just his scientific pursuits, but also his ever-present affinity for art. “I need the escape from science that is provided by immersion into the world of art,” he says. “And I get inspiration by venturing into galleries in Chelsea or, as recently, going to the Metropolitan Museum of Art for an afternoon to absorb Marville’s photographs of Paris.”