Catherine Dulac, Lee and Ezpeleta Professor of Arts and Sciences and Higgins Professor of Molecular and Cellular Biology, has been awarded a 2021 Breakthrough Prize in Life Sciences for her pioneering work identifying the neural circuitry that regulates parenting behavior in both males and females.
“One of the beauties of science is teamwork,” said Dulac, who described being “shocked” upon receiving the news. “All of this work was thought through and performed in very close collaboration with grad students, undergraduates, and postdocs. You never think alone.”
Now in its ninth year, the Breakthrough Prize was created to celebrate consequential work of the world’s top scientists and to inspire future researchers. The $3 million awards are among the field’s top recognition in mathematics and fundamental physics, as well as the life sciences.
Dulac, who is also a Howard Hughes Medical Investigator, joined the Harvard faculty in 1996. She has long been driven by a deep fascination with the interplay between social interactions and the human brain. In animals, social responses are typically distinct in males and females. Female mice, for example, spontaneously build a nest and start caring for infants, even if they are from another female. Male mice, by contrast, tend to attack infants. Her winning research identified the specific brain cells and neuronal circuits that control these behaviors and questioned the long-held belief that different neuronal circuits develop in male and female brains.
When she joined Harvard as a junior faculty member, Dulac set to work investigating and identifying families of pheromone receptors, the molecules expressed in a specialized sensory tissue of the mouse that detects social cues, called the vomeronasal organ (VNO). By genetically modifying the function of VNO neurons, she discovered that sex-specific social behaviors can be altered. About 10 years ago, these experiments led her to study the hypothalamus, the main brain area downstream of the VNO system that controls sex-specific behaviors.
“It’s not that the circuitry is different; it’s the regulation of that circuitry that’s different,” she said. “The male brain has the same circuitry for parenting behavior that is present in females, and females have circuitry for infanticide that males have. If we kill these neurons in the female brain, they are no longer parental. If we activate them in males, they become parental.”
Dulac, who served as chair of MCB from 2007 to 2013, called the prize gratifying because when she started her research, some discounted the work and considered her approach inferior.
“Social behavior used to live in either the realm of psychology or ethology [the study of animal behavior, usually with a focus on natural conditions]. Most neuroscientists typically work on the cortex while we looked at hypothalamus, the area of the brain that organizes social behaviors. They viewed it as less,” she said. “[But] humans are very arrogant. Evolutionary speaking, we are still animals, eating, sleeping, mating, parenting — these are things we have to do. These behaviors do not live in the cortex. They all come from the hypothalamus, and the corresponding circuitry tends to be very conserved across animal species.”
FAS Dean of Science Christopher Stubbs called Dulac’s award “well-deserved.”
“I’m thrilled to see Professor Dulac’s outstanding contributions be recognized with the prestigious Breakthrough Prize,” he said. “Her ability to bring diverse techniques to bear on important problems that link neurons to behavior is truly remarkable. We celebrate this well-deserved recognition of her skill, her insight, and her scientific depth.”
Dulac said this “new frontier” in neuroscience is one that might have enormous impact on medicine.
“For example, I was stunned to discover in the literature that 10 to 20 percent of women in the U.S. suffer from postpartum depression. I do not know of any mental illness that affects so many people. It’s very serious and our work, which provides an unmechanistic understanding of how parental behavior is controlled in the brain, will hopefully inspire more clinically oriented research to identify how and when this neural circuit misfunctions, and what to do about it,” she said.
Dulac’s passion for research is equaled only by the enthusiasm she brings to her classroom and to the younger generation of scientists who work in her lab.
“What is fascinating to me is this confrontation of ideas. Everybody brings something to the table. Some ideas are better; some are worse. But as a whole they form something that makes us move ahead,” she said. “Science in the U.S. tends to be very informal, which is different from France, where I was raised. There we were taught to respectfully defer to your professor’s ideas. This always seemed wrong to me, which put me in a lot of trouble when I was a student. You have to be able to contradict your mentor to keep the discussion going, to see if the idea floats or not. The best thing that can happen in my lab is when someone proves me wrong, because it means that there are very smart people in my group. Sometimes I am right; sometimes I am wrong; and sometimes everyone is wrong, which means that, collectively, we have not thought about a problem hard enough. The results of our experiments will always be there to tell us that.”
Dulac, who has pivoted during the pandemic to work on the social effects of isolation on the brain, is a member of the American Academy of Arts and Sciences, the French Academy of Sciences, and the American Philosophical Society. She is the recipient of the 2019 Ralph W. Gerard Prize in Neuroscience, the 2017 Scolnick Prize, and the National Academy of Science’s 2015 Pradel Research Award. When given her endowed professorship at Harvard in 2018, she used the stipend to fund a fellowship for an undergraduate in her lab. That student, Melonie Vaughn, now a graduate student, is one of dozens who keep in touch regularly.
“A lot of people come through my lab, and I need to be supportive,” she said. “Melonie just sent me an email about how excited she is of just joining a lab and applying for her first NSF grant. It warms my heart to think about that.”
This year’s other Breakthrough winners in Life Sciences are David Baker (University of Washington), Yuk Ming Dennis Lo (The Chinese University of Hong Kong), and Richard J. Youle (National Institutes of Health). Martin Hairer (Imperial College London) won the prize in Mathematics, and Eric Adelberger, Jens H. Gundlach, and Blayne Heckel (University of Washington) won the prize in Fundamental Physics.