David van Essen, Alumni Professor of Neuroscience at Washington University St Louis School of Medicine, has been a pivotal figure in non-human and human neuroimaging. David is the principal investigator on the Human Connectome Project, and has made substantial contributions to brain parcellation methods, functional neuroimaging, and data sharing initiatives. Here, we find out about his early work in cortical cartography and his early experiences with OHBM.
Nils Muhlert (NM): I'm joined here today with Professor David van Essen for the OHBM Oral History Initiative, celebrating 25 years of OHBM. Thank you, David, for joining us. First, can you tell us about your background and how you became interested in neuroimaging?
David van Essen (DvE): I started as a vision neuroscientist. I got interested in the visual cortex because I was working with professors Hubel and Wiesel, who received the Nobel Prize for their studies on vision. That hooked me on that general area for many years.
When I did postdoctoral work in University College London, I started working on the visual cortex of macaque monkeys. That got me into making maps of the cerebral cortical surface. It was an important transition because the tradition of those early days was to draw results on slices of the brain. But I realized that the same way that Earth maps help us navigate the earth, flat maps of a monkey brain would help us navigate that terrain. So that became a driving theme. I became a cortical cartographer, as it were.
I continued as a cortical cartographer for many years while on the faculty at Caltech. I realized that the maps I was making of monkey brains could be extended beyond the visual cortex to the entire cerebral cortex. In principle, they could be extended to the human cerebral cortex. I wanted to get my feet wet in human neuroimaging, but Caltech at that time had no opportunities.
I moved to Washington University in St. Louis, and connected with Mark Raichle, Steve Peterson, and other colleagues there. That got me rooted in that community and I started not doing neuroimaging myself, but analyzing results that others had generated in the context of cortical maps that I was familiar with. A very important event right after I arrived at Wash U was meeting Peter Fox, who had been a collaborator and colleague of Raichle. He had moved to San Antonio and started organizing the winter Brain Map events. We had conversations about having a different annual meeting that would be open rather than closed in invitation.
It was one of those meetings in December of 1994 that the commitment was made. Bernard Mazoyer stuck his neck out to commit to organizing the meeting in Paris. At that time, I was still working mainly on monkeys, not doing neuroimaging myself, not sure whether I would attend. Fortunately, I was invited to give a lecture. Per Roland came up to me at the Paris meeting and said: "We need some animal models. The title is human brain mapping but it should be broader than that." I was more than happy to join in.
In Paris, I participated in the excitement of the very first HBM meeting, where no one knew what to expect. It turned out to be spectacularly successful - even though the one vivid minor memory I have is that the poster boards were extremely hard to attach pins to. I had a tremendous struggle just doing that! Later, at the town hall meeting, there was a general enthusiasm for making this an annual event. But also a gradual realization that to make that happen, somebody's got to get their act together. It turned out that Peter Fox's San Antonio meeting was a focal point for a number of us, all volunteering to spontaneously, in an ad hoc way, become a working group or committee that would draft a plan.
Alan Evans, Peter Fox, Steve Peterson, and a number of others put our heads together and drafted a plan for what would be discussed at the Boston meeting. We set out the boundary conditions, what it would be called and how it would operate. That led to the vigorous, now entertaining, but hotly debated at the time, discussion of whether this should be the Organization for Human Brain Mapping or what became known as the SHABOOM, the Society for Human Brain Mapping. It's been noted that, in retrospect, that probably wasn't as important an issue as it seemed at the time. In any event, it helped frame the project. It helped constructively engage the community to think hard about what it was they wanted, and to listen to the discussion and debate that was held in Boston.
The meeting in Boston is where Alan Evans pulled out his helmet for mock protection against the angry mob. That took the heat out of the situation and the net result was a resounding enthusiasm for establishing an entity and, on balance, an organization. Another part of that discussion was setting out the mechanics for a more stable entity. At this year’s annual meeting David Kennedy brought out several pages of paper that had been passed around for people to vote on: what they wanted, who the board of directors would be - and who would later become the OHBM Council. I was fortunate enough to be one of those who were voted in. Then, lo and behold, I was asked to become chair of that committee. During the following year, we set up proper bylaws, not just name who's running the show, but the process, who would be the officers, etc.
These standard operating procedures are not too complicated but important to get right. That was put forward to the membership at the Copenhagen meeting and resoundingly approved. As they say, the rest is history. Once the Copenhagen meeting occurred, all the ducks were lined up in a row to make the organization run smoothly and evolve. It's been great fun to see that evolution, both in terms of growth of the community, growth of the field and transitions. The organization certainly now feels more like a society.
NM: And from those early beginnings, what do you see happening with neuroimaging now, particularly in the US?
DvE: It's fascinating to see the explosion, not just in terms of the number of investigators, but in the richness of the portfolio of tools and approaches that start at the front end with data acquisition. That's still a hot issue, because we need to take out as much high quality data as possible from MRI and other methods to give us the best shot at exploring how the brain works and functions.
But it certainly doesn't stop there. The way I frame it is the field as a whole needs to move towards a coordinated effort. Project by project, whether small or large, to get the best possible data to preprocess it as carefully as possible, to analyze it as thoroughly as possible, to interpret it as rigorously as possible, including being aware of over-interpretation or false positives and false negatives. These are hot button issues to this day. Another important part of it is the neuroinformatics side, the data storage and management, and data sharing.
Data sharing has been one of my passions for more than two decades now. In the early days, Peter Fox was another of those who were pounding the drum for data sharing. But there was, to some degree, a sense that we were voices in the wilderness, because there wasn't a whole lot of attraction from the majority of neuroimaging investigators who felt more like hoarding the data that is being mined. And that's now changed dramatically and that's wonderful to see.
NM: And so you've touched on some of the areas that you've been involved in, but what contributions would you say you're most proud of in your career?
DvE: I'll admit to being proud of a number of things, and part of it is just being a cortical cartographer broadly read who's interested in structure, function, development and evolution of the brain and particularly the cerebral cortex. As one example, cortical development is not what I spent most of my working hours on, but I developed a theory of tension based morphogenesis that can account for how the cortex gets its folds. I first presented that at OHBM and got very warm, enthusiastic reception and that helped me appreciate the opportunity to bring that to an audience and get some focus on issues of development. In another sense, the opportunity to work on a very broad framework came up in a very significant way for me when the Human Connectome Project came on the radar screen. I led a consortium along with me a little gerbil to drive that effort. And that has been very rewarding to carry out the process and very gratifying to see. Even today, many talks and many posters are taking advantage of the Human Connectome Project with freely shared data sets and use it for analyses of structure, function, and even development and, obviously, connectivity as well.
NM: And, and so, going back to which OHBM, what memories would you say particularly stand out from the annual meetings that you've attended?
DvE: The early days do stand out: the Paris meeting, the Boston meeting. The excitement of being part of an enterprise that was just getting its feet on the ground. And then I remember the main meetings in Sendai, in Beijing, and Vancouver. Just a wonderful collection.
NM: And so walking around the auditorium here in Rome, how do you find that it's changed in terms of the makeup of people or the types of events that are on offer?
DvE: It's great to see the diversity in terms of age and international composition, although that has been a strength of the OHBM from the early days. I don't know that it's changed so much but the fact that it's very broad. It's great seeing lots of women present and on the stage, front and center; that's been a definite notable feature, particularly at this meeting.
One of the things I attend to when I go around posters is how many capitalize on the use of surface based representations, going back to what I was mentioning earlier. As a cortical cartographer, the best way to make maps from my view, is to make surface models rather than volumetric slices. And it was, frankly, painful in the early years to again be feeling somewhat of a voice in the Wilderness in those early days and only a smattering of posters would make use of surface models. Today, almost half of the posters in some sections are doing that. To me, that's an extremely important transition to capitalize on making best use of the data in neuroimaging studies.
NM: Related to that, how was your kind of anatomical training, were you involved in teaching neuroanatomy in the early days? Or has this been something that's developed over the years?
DvE: When I came to Wash U, I agreed to be a course master for the first year medical neuroscience course. So I've taught hardcore neuroanatomy medical students style for well over two decades and learned a lot in the process myself. Fundamentally, even before that, I was rooted in the tradition that anatomy and function are intimately interlinked and you can't make sense of one without the other. Thus, I have a very strong anatomical grounding,even when I'm thinking about other aspects of functional organization.
NM: Great! And what do you see as the future of neuroimaging?
DvE: I think it is generally fairly bright. The challenges remain daunting. I think the optimism of the early years that we're on the verge of identifying biomarkers for brain disorders has been sobering to realize how hard a problem that is. That's for reasons that we're now getting a better appreciation for why it's so hard. I think we have to take the long view and realize that the past two major successes are in better understanding and diagnosing brain disorders. But to me, we're still in the infancy stage because we desperately need progress on that front. To achieve that progress, I think the best way to make headway on major scientific achievements is to do the best possible analysis, collect the best possible data, analyze it in the most thorough way possible, and then freely and openly share that data so that the community can dive in and help further analyze and interpret it. If that mindset continues to thrive in the OHBM environment, I think it will continue to do a major service to the field.
NM: Professor van Essen, thank you very much for joining us.
DvE: My pleasure.