Ben Barres (1954-2017)

Almost two years after being diagnosed with pancreatic cancer, Ben Barres, Professor of Neurobiology at Stanford University, passed away on December 27th 2017. Ben will be fondly remembered as a pioneer in neuroscience, a great mentor, and a strong and eloquent advocate for equality in science. Through his highly original work both as a postdoc and independent scientist, Ben transformed our understanding of glial cells. Together with his colleagues and trainees, he showed that glial cells are not simply ‘support cells’ of the nervous system, as they had been referred to for decades, but play an active part in neural circuit development, maintenance, and function in health and disease. His scientific discoveries are now part of major textbooks and will influence the work of many generations of scientists to come.

But Ben also passionately contributed to help make science a career possibility for everyone. As a transgender individual who transitioned from female to male in his forties, he experienced what it is to be a scientist of both sexes. He did not hesitate to use his personal experiences to sensitize others about gender discrimination and to promote equal opportunities for all, including LGBT and other minority groups. Perhaps one of the most touching stories he told was that, upon changing sex, he was finally able to complete a full sentence without being interrupted by a man. This was a powerful message that opened the eyes of many to the difficulties faced by women in science. Ben fought hard against implicit bias, including a brilliant and famous letter he wrote to Nature (Barres, 2006) following the Larry Summers incident (Summers, then President of Harvard, suggested in a speech that the paucity of elite female scientists might be due to intrinsic differences in aptitude).

It would be easy to focus this piece on Ben's advocacy activities or his outstanding scientific accomplishments, but this has been done very well in several obituaries that were written by my colleagues in recent weeks (Huberman, 2018; Raff, 2018; Tessier-Lavigne, 2018). Instead, I thought one of the best ways to pay tribute to Ben was to talk about an aspect of his career that he valued the most: training and mentoring. Many of Ben's unique mentoring activities, such as the infamously intense but highly rewarding lab meetings, have been nicely discussed by two of his former trainees (Allen and Daneman, 2018). To avoid repeating what has already been said, I have therefore chosen to write about my personal experience as a trainee in the Barres lab. Considering my unique situation in the lab, I think this story illustrates quite well the kind of mentor and person that Ben was.

I first met Ben when he visited my poster at the Society for Neuroscience meeting in Fall 2000. I was then a postdoctoral fellow with Ben's own former advisor, Martin Raff. My poster had nothing to do with glia; it was about asymmetric cell division and neurogenesis in the retina. Despite this, Ben was very interested and had lots of questions: I still consider that discussion one of the most stimulating and engaging I have ever had at one of my posters. Not surprisingly, then, when it was time the following year to decide what to do when Martin would retire, I thought about Ben and contacted him to see if there was a possibility to pursue my training in his lab.

On September 10th 2001, I spent the day in Ben's lab, giving a talk and discussing with everyone. At the end of the day, I had a long discussion with Ben that I recall very well. He asked me why I wanted to do another postdoc and suggested that I should look for an independent position. I explained to him that I did not feel ready to make this move and that I really wanted to finish a project that I had started in Martin's lab. I also told him that I was not prepared to commit to staying in his lab for more than two years. Thinking back, these were rather unreasonable requests to make. But Ben did not flinch. He said I would be most welcome in his lab, but at the same time he warned me that I would be the only one working on neurogenesis. It was fine with me. I had the possibility to work with a brilliant scientist in an outstanding and highly supportive training environment.

When I went to the airport the next morning to fly back to London, I was excited about the opportunity coming up. But when my flight was cancelled due to the September 11th attacks, I didn't really know what to do, so I called Ben, who was the only person I knew in town. Without hesitation, he offered that I could stay at his house while I waited to be rebooked. During this time, we played tennis, talked about hockey, and of course had many scientific discussions. This allowed me to get to know Ben better and confirmed that I had made the right decision. Ben was a great scientist, but also a caring person.

In retrospect, Ben's generosity did not stop when he offered me a place to stay; it was further exemplified by his welcoming me in his lab. Not many would have hired a postdoc to work on a topic outside the lab's main interest and for a shorter than average period of time. But Ben offered me space and funding to carry out my projects, which led me to an independent position two years later. Anyone who knows Ben will know why he did that. He was genuinely interested in the science: he did not care so much what the questions were, as long as they were interesting. He was passionate and always happy to offer insights and guidance. I have great memories of the many stimulating discussions at lab meetings or improvised in the corridor, where we would sometimes chat for more than an hour.

During my time in the lab, I witnessed Ben's remarkable qualities as a mentor. One that struck me the most was his dedication to promoting the careers of the people in his lab. He did not hesitate to step aside and leave the spotlight to his trainees. When he received invitations to speak at meetings, Ben would often suggest that a postdoc or a student takes his place, convincing the organizers that they would do a better job anyway. This allowed many of his trainees to be placed at the forefront of the field very quickly, leading to unique career opportunities. And when he gave talks, he made sure that everyone in the audience knew who did the work and how great they were. This was very important to him, and shows how much he cared about people in his lab – who he affectionately called his family. It is therefore not surprising that Ben has trained an impressive number of people who went on to have their own independent research careers in academia or the private sector.

With the passing of Ben Barres, the world of science has lost a monumental figure. But one thing that comforted him towards the end of his life, and that he was most proud of, is that he leaves behind a large number of ‘scientific children’. It is now their turn to be great scientists and mentors, and to advocate for equality in science, such that Ben's legacy remains.