Neuroscientist BJ Casey takes a decidedly maternal approach to mentoring the students and postdoctoral fellows in her lab, so watching them rotate through her lab is bittersweet. In the case of one mentee, Assistant Professor Conor Liston, Casey hasn’t had to say goodbye: Liston chose Weill Cornell for his M.D.-Ph.D. studies more than a dozen years ago and returned as faculty this past year.

Their relationship, chronicled in Episode Two of the online video series Inside Medicine at Weill Cornell, has enriched each other’s research into brain development and function. For Casey, mentoring Liston has allowed her to nurture a junior investigator into a colleague. And for Liston, Casey’s mentorship has shaped everything from his approach to scientific experimentation into mood disorders to how he guides the up-and-coming researchers in his own lab today.

While Casey jokes that their shared Irish heritage accounts for their lucky connection, she says the two instantly recognized in each other not only a mutual interest in the use of noninvasive imaging to study child brain development, but a similar passion for scientific inquiry. “Conor is one of the most exceptional thinkers I’ve had the opportunity to meet. He thrives when there is a roadblock to him understanding a scientific question,” says Casey, director of the Sackler Institute for Developmental Psychobiology at Weill Cornell.

“I think that you recognize your colleagues and individuals who are really in science because they love the science and they really have a passion for scientific discovery,” she adds. “And that creates an almost manic discussion about their work. It’s easy for you to connect with people like that, because we thrive on each other’s enthusiasm. I feel very lucky to be able to work with him.”

Casey likes to act as a “sounding board” for her mentees, providing the support they need to help them achieve their own goals. It’s a sensibility she patterns after that of her mother, who let her children know that she believed they would make decisions that were best for them.

“The one thing you want to make sure you don’t do is to get in another scientist’s way,” says Casey, who has mentored more than two dozen M.D.-Ph.D. and Ph.D. students and postdoctoral fellows since she arrived at Weill Cornell in 1999. She also interacts with the nearly 20 young investigators who rotate through the institute each summer. “When you see them activated, you want to do everything that you can possibly do to facilitate that, and to keep that creativity and that productivity going.”

Her open-minded approach was especially useful to Liston, a neuroscientist and biological psychiatrist, when he was developing his doctoral thesis on the effects of chronic stress on a brain network that regulates attention. While much of Casey’s work focuses on children, Liston wanted to focus on young adults. “She afforded me the flexibility to study what I wanted to study,” he says. “Many ideas originated with both of us, but none could have happened without her guidance and support.”

Perhaps not surprisingly, Liston now is a mentor himself, treating his mentees as peers and instilling in them the confidence to take chances and ask the questions that drive their passion for science. He advises half a dozen students, postdocs and research technicians not just on his lab’s work on depression, anxiety and autism, but their own interests in those areas. It’s something that makes Casey “smile a whole lot.”

“The critical elements of good scientific thinking, which I learned early on from BJ, are all about coming up with hypotheses but being open to the possibility that they won’t be correct,” Liston says. “If you set out to prove an idea, you’re not likely to run the experiment well or analyze the data well, and you won’t be open to the possibility of being wrong and are likely to come up with answers that are incomplete approximations of the truth. When a hypothesis turns out to be wrong, it forces us to rethink the way we approach problems and forces us to come up with better, more accurate theories.”

Jordan Lite is senior editor for Weill Cornell Medical College.