Q. The map published by the Human Connectome Project in 2016 is a milestone. It detailed 180 regions of the brain, 97 of which hadn’t been known. But you started mapping the brain with pencil and tracing paper. How has your idea of an image — or a map — changed?
A. A useful analogy is to think of the maps of the Earth. Some show mountains and rivers and other geographical features. Others show countries, states and other political subdivisions. Each serves a different purpose. When we make maps of the folded cerebral cortex, these are analogous to geographical earth maps. Our maps of brain function are akin to maps of political subdivisions.
Early Earth maps were quaint and amusingly inaccurate, but now we enjoy the extraordinary precision of Google Maps. Brain maps have dramatically improved as well, though not to the same degree. In both domains, map-makers share similar fundamental objectives, but the tools continue to evolve.
Q. You found your field of study when you came across a book on the brain after your sophomore year at California Institute of Technology. What advice would you give to students who are interested in science, but haven’t found a field that really grips them?
A. I was interested in science from early childhood. In high school, I was fascinated by math and physics. In college, I realized my brain wasn’t really "wired" to become a theoretical physicist. I became a chemistry major instead, but chemistry didn’t ignite the kind of passion that sustains a career. By good fortune, I chanced across a book about the brain and immediately became hooked.
One lesson is that success in science requires intense work but also a fierce passion for your area of study.
Q. Some scientists have expressed confidence that we’ll come to understand consciousness just as we have come to understand the human genome. You’ve expressed doubt. What do you think might be beyond our reach?
A. Again, I’ll use an analogy. We have made great progress in characterizing the human genome. This includes incredibly accurate mapping, or sequencing, of all three billion "base pairs" (the genome’s alphabet) in the genomes of each of many thousands of people. Yet there are still vast mysteries about how genes are turned on and off to orchestrate the development of healthy cells, organs, and people or what goes wrong in most genetic disorders.
In the brain, there are 80 billion nerve cells and trillions of connections, or synapses. Accurately mapping all those cells and their connections — what we call the connectome — is currently impossible for the human brain, though it may become feasible for laboratory animals such as fruit flies and even mice. Nonetheless, there are countless exciting discoveries about the human brain still on the horizon.
A. What should the public understand about this research?
A. There are two reasons to pursue basic research on the brain. The first is human curiosity. How do our brains work? What makes us think, sing, and feel love or hate? Such questions fascinate the lay public as well as neuroscientists. Second, we must pursue this basic research in order to better diagnose, treat, and prevent brain disorders and diseases. All of us have had the experience of seeing someone with a debilitating brain disorder. We need to sustain our efforts to identify cures and provide better treatments.