Rethinking the way we think about thinking: A Q&A with Dan Feldman

January 4, 2024

by Alexander Rony

Photo of Dan Feldman

Neuroscience is in a historic era of major discovery, according to Dan Feldman, a professor of neurobiology at UC Berkeley.

For years, neuroscience has steadily grown as a major strength at Berkeley. Now, to cement Berkeley's place at the forefront of innovation, Feldman is leading the effort to form a cohesive Department of Neuroscience, the first new department within the Division of Biological Sciences in more than three decades. Soon, faculty who study the brain from diverse perspectives, from neurobiology and psychology to engineering and vision science, will be able to unite under one banner.

Feldman talked with UC Berkeley writer Alexander Rony about how the field of neuroscience is changing society for the better, the advances that Berkeley researchers have contributed, and where neuroscience will lead us in the future.

Alexander Rony: What first attracted you to the field of neuroscience?

Dan Feldman: I've long been fascinated with how learning works in the brain. How is it that you remember someone you met when you were 10 years old up until you're 80? That's a remarkable feat for a biological system to perform and indicates that memory traces somehow exist in the physical structure of the brain. But before understanding learning, you need to understand how nervous systems process information in the first place.

My lab studies this question by asking how we sense the physical world around us. We take measurements in mice to assess how the brain constructs the internal stream of images, sounds, and feelings of the sensory world. This is a construct of your brain based on the electrical impulses that your brain receives from your fingertips, your eyes, and your ears.

What are some significant ways in which neuroscience has already impacted society?

There are so many ways! Let's start with the redefinition of addiction as a disease rather than a moral failure. And the understanding that the brain takes many years to develop has helped change how the justice system views the legal responsibility for acts by children and teenagers. Likewise, neuroscience has shown that brain activity bears signatures of a person's educational level and childhood experiences, and this has informed the debate about equity.

Another example would be neurodiversity. Brains are individually distinct, and people have different communication, perception, and thinking styles. These are not deviations from a norm; they represent the natural range of ways people are built.

How has Berkeley been at the cutting edge of neuroscience research?

Many technologies driving neuroscience discovery forward were invented, optimized, or applied at Berkeley. One of the most powerful technologies in studying how the brain works at the circuit level is called optogenetics, in which genetic tools are used to make neurons sensitive to light. Flashing a light can then turn brain cells on or off. One of the earliest optogenetic constructs was developed here at Berkeley, as were later methods that study how neurons communicate at synapses. Recently, optogenetics has been applied at Berkeley to restore vision in animals with retinal degenerative disease.

Another example is fMRI, which is a type of brain imaging that can see functional activation of the brain. Some of the founding physical principles of fMRI scanners were worked out at Berkeley. Even more exciting, the world's most spatially precise fMRI machine has just built on the Berkeley campus. It will give a much better view of what's "going on under the hood" as a person thinks, feels, sees, and remembers.

Berkeley is also engaged in the Brain Initiative's cell census. Can you talk about the importance of that project?

One of neuroscience's biggest goals and challenges has been to develop a complete wiring diagram of the brain. If you think about it as a gigantic circuit, you need to understand what the components are. Those would be the cell types in the brain. Defining a cell type is a surprisingly complicated and nuanced task. Berkeley is one of the early sites that developed the computational methods used to analyze genetic signatures that define discrete cell types within the brain. John Ngai, who was a faculty member in neuroscience at Berkeley for many years, left to become the head of the Brain Initiative at the National Institutes of Health.

Our field is well on the way to that wiring diagram — the connectome of the brain. It's going to be coming in the next couple of decades. We'll essentially have a computational resource — a lookup tool — that we can use to figure out how different regions of the brain might be performing their functions. That will be the equivalent of the human genome for understanding the nature of brain computations.

You've been deeply involved in the effort to build a new neuroscience department at UC Berkeley. How would a unified department benefit education and research?

Berkeley has done well in building its neuroscience effort. We now have around 70 faculty on campus doing some form of neuroscience who are part of this great collective effort. But, like most universities, we've put those faculty into many distinct departments like biology, chemistry, physics, and psychology. This siloing of faculty gets in the way of major research advances in neuroscience, which happen at the intersections between these traditional disciplines.

That's not the way to have the strongest research advances or provide the best education in a vertically integrated field like neuroscience. You want truly interdisciplinary training to take place within the same department — by sharing ideas, tools, and resources through tremendous interaction.

On the undergraduate level, we've been offering only fragments of a neuroscience education for many years. Students in the Molecular & Cell Biology Department's neurobiology emphasis don't learn about cognitive neuroscience or computation. Students in psychology — a popular major that is the number one program in the country — can't specialize in neuroscience and typically only take one or two neuro courses during their major. The new Neuroscience Department will offer an integrated neuroscience major that spans those different levels.

On the graduate level, the Helen Wills Neuroscience Institute runs the existing neuroscience Ph.D. program. The program is very successful; it's in the top eight or so in the country. We're going to adopt and expand it, and both the department and the Helen Wills Neuroscience Institute will serve the Ph.D. program. That will give students a tremendous choice of faculty and research opportunities.

What is needed to expand the undergraduate and graduate programs?

In order to ensure that we can continue to compete against our main competitors — who are generally private elite institutions double the size of ours — we need a way of increasing the number of graduate students. The mechanism has to be through graduate fellowships. We already have the faculty at Berkeley to nucleate a great department, which will be one of the strongest in the country.

There will be some need to hire additional faculty in certain key areas. Computational neuroscience is one of them, as is cellular neuroscience related to disease. In addition, the department is interested in expanding into the broader area of neuroscience and society — from education to law to health. How do we inform decisions that judges have to make or that state legislatures make when they pass laws? How do we inform educational policy or social policy about equity?

Do Berkeley's neuroscientists have any promising medical partnerships?

Absolutely, we have many collaborations with UCSF and other institutions. Even at Berkeley itself, about a third — or maybe even half — of the neuroscience labs have some disease-related question they're pursuing. We have many groups working on neurodegeneration and neurodevelopmental disorders, as well as on addiction, depression, and epilepsy.

There are a lot of interesting developments here. An example is blindness. There are several forms of blindness that involve the degeneration of neurons in the retina of the eye. Once those neurons have degenerated, unfortunately, there's no way to get them back. Several research groups here at Berkeley have developed promising optogenetic strategies to allow the remaining cells of the retina to directly sense light and, therefore, be able to see again.

What advice would you give to a new undergraduate student majoring in neuroscience?

A decade ago, I would have said that the choice to study neuroscience was a route into a pre-health or basic research career. There weren't many other options because there wasn't a neuro-related set of industries in the U.S. That has really changed.

Now, neuroscience is a great preparation for biotech and neurotech startups; for artificial intelligence, computation, and data science; and for traditional pharmaceutical and health-related industries. The technical and conceptual skills you gain are incredibly valuable for this wide variety of careers. In that sense, I would say to a student, "You've chosen the right major because you're at a time when you can use that major to do many different things, which are not only interesting, rewarding careers but are also growth industries."

If we look back 10 years from now, how would you determine that our neuroscience department has been successful and a valuable contributor to society?

Our educational mission is critical — our students' successes and impact in their own fields and careers will be an important outcome that will make us proud.

At the research level, it would be the pace of discovery. Neuroscience is clearly in its era of major discovery. It's happening now. There's been talk for decades that neuroscience is about to explode. We're about to understand how the brain works, and we're about to solve various diseases. We're finally ready to do it as a field — in fact, it's already happening.

I think we're going to look back 20 or 30 years from now and say that the 2020s and probably the 2030s were the time that neuroscience moved from its phase of trying to iron out what theories of the brain might look like to actually discovering how the brain really works. Berkeley is already part of this wave of discoveries, and forming a department will allow us to reach the next level.

Neuroscience is clearly in its era of major discovery. It's happening now.

Professor Dan Feldman