The World and Ourselves:
A Conversation with Torsten Wiesel

Trained as a physician in Sweden, Dr. Wiesel arrived in the United States in the 1950s, when the field of neuroscience was just beginning to take shape. There he met the neurophysiologist David Hubel, MD, who became his lifelong “scientific brother.” And by focusing on the study of vision, the two of them figured out exactly how it is that the brain constructs reality as we all experience it.

Dr. Wiesel and Dr. Hubel discovered that visual information is processed by neurons that respond to very specific kinds of stimuli—some to edges, some to motion, some to certain orientations in space, and so on. These responses are the building blocks of everything that you see.

They later identified critical periods in development during which this visual circuitry takes shape, showing that the world we see is never a given, but a direct product of how we interact with it. Their Nobel Prize in Physiology or Medicine, in 1981, recognized the impact of this work not only for neuroscience, but also for our ability to understand ourselves—literally—as part of the reality we inhabit every day.

That impact extended into Dr. Wiesel’s intellectual leadership. As President of The Rockefeller University, from 1991 to 1998, he oversaw the creation of several major research centers, including the Zachary and Elizabeth M. Fisher Center for Research on Alzheimer’s Disease—championing a fundamental vision of science driven by humanistic purpose.

In this conversation, Dr. Wiesel reflects on the roots of that vision, sharing his hopes for the future of neuroscience as a force for insight and responsibility.

You were the President of The Rockefeller University when the Fisher Center Laboratory was established in 1995. Can you take us back to those early discussions?

The Fisher Center Laboratory was established through a visionary philanthropic partnership between Mr. Zachary Fisher and Mr. David Rockefeller. The Center was conceived as a unifying force for The Rockefeller University’s wide-ranging efforts to understand the causes of Alzheimer’s disease and to develop effective therapies.

From its inception, the Fisher Center Laboratory has pursued this mission by integrating fundamental laboratory research with clinical studies involving patients. This combined approach has enabled discoveries at the most basic levels of biology to inform translational and clinical advances, accelerating progress toward meaningful treatments for Alzheimer’s disease.

In a letter to Mr. Fisher in 1994, I wrote that “one of the highest objectives of my administration has been to create a center dedicated to finding a cure for Alzheimer’s disease. Thanks to your generosity, my dreams can now be realized.”

You also worked with the Laboratory’s first director, Paul Greengard, for many years. How did you envision the Fisher Center Lab as part of Rockefeller’s broader research agenda?

Part of what made this vision possible was the partnership between the Foundation and Rockefeller University professor Paul Greengard, PhD. Dr. Greengard was a pioneering neuroscientist whose discoveries transformed our understanding of how nerve cells communicate. Awarded the 2000 Nobel Prize in Physiology or Medicine, his work revealed the fundamental role of protein phosphorylation in signal transduction in the nervous system, providing a molecular framework that continues to shape modern neuroscience.

Under his leadership, the Fisher Center rapidly grew in stature, becoming a hub for innovative research at Rockefeller University and earning international recognition within the scientific community. Greengard’s insistence on rigorous, curiosity-driven science helped attract exceptional investigators and fostered a collaborative culture that remains a hallmark of the Center today.

That crucial work continues more than thirty years later. The Fisher Center has become a cornerstone of Rockefeller University’s academic and clinical research environment, supporting one of the largest concentrations of scientists dedicated to neurodegeneration and Alzheimer’s disease anywhere in the world. Today, researchers are harnessing cutting-edge technologies—from advanced imaging and molecular tools to powerful computational and data-driven approaches—to tackle the complexity of these diseases. While much remains to be uncovered, Rockefeller scientists continue to meet that challenge with the same ambition, creativity, and resolve that defined the Center’s founding.

You originally trained as a physician. In what ways do you think your medical background shaped your path as a researcher?

From a very young age I was interested in understanding why some individuals were patients in the large mental hospital where I grew up and where my father was the director and chief psychiatrist. Our family lived in a large fenced-in area, making it possible for me to interact and become friends with patients in the parks as we played soccer and other games. In retrospect, it is no surprise that I decided later to enter medical school and to follow my father’s path to become a psychiatrist.

Another important factor was that my older brother became schizophrenic, and I had a strong desire to better understand the basis of his disease. Once fully trained and a certified medical doctor, I was struck by the lack of adequate treatment of mental illnesses and returned to the university to do basic research.  Thus, my drive to understand the brain has always been driven by my medical background and to help those in trouble.

You have spoken about the value of collaboration in scientific research. What made your partnership with David Hubel so effective, for example? How did you cultivate things like creativity and curiosity in the context of your lab work?

I met David at Johns Hopkins University, where we were both postdoctoral fellows. Although we were trained physicians—David earned his medical degree in Montreal, and I at the Karolinska Institute in Stockholm—neither of us had followed a traditional graduate path or earned a PhD. Nonetheless, we complemented each other well enough to design and execute original research which led to a fruitful and successful long-term scientific collaboration.

I often refer to David as my “scientific brother” because in our often night-long experiments we learned to know and appreciate each other. Our research unfolded over two decades of close collaboration, marked by moments of excitement and inevitable frustration, all driven by a shared desire to understand the brain circuits that make visual perception possible.

Our regular schedule was to carry out two experiments per week, on Tuesday and Thursday, while meeting on Wednesdays to analyze data and plan the next experiment. In addition to teaching the medical students about the wonders of the brain, we occasionally demonstrated the actual responses to visual stimuli from single neurons in the visual cortex.

Looking back at your research trajectory today, what do you think was the biggest conceptual leap in your experiments on the visual cortex and beyond—the part that was most difficult for others, and perhaps even for you, to understand at the time?

We learned that major breakthroughs in research require more than careful planning and rigorous execution. There is often an element of luck—and, just as importantly, the ability to recognize when luck appears. For us, that moment came with the realization that visual perception is built on a surprisingly simple code: neurons in the visual cortex respond selectively to lines and contours with specific orientations.

This discovery revealed a fundamental strategy the brain uses to make sense of our complex visual world. By breaking down complex images into basic elements early in processing, the brain creates a foundation upon which higher brain regions can recognize and identify objects—faces, familiar scenes, and objects—we encounter every day. What began as a chance insight ultimately reshaped our understanding of how the brain transforms raw visual input into meaningful experience.

What areas of brain research most excite you now?

Some of the most exciting work underway today comes from Rockefeller faculty member Priya Rajasethupathy, MD, PhD, whose research sits at the intersection of memory, neural circuits, and neurodegenerative disease. Her lab is uncovering how memories are formed, stabilized, and, critically, how they begin to unravel. By asking what happens when neural circuits are disrupted—and whether those circuits can be protected or restored—her work speaks directly to the central challenges of Alzheimer’s disease. 

Dr. Rajasethupathy combines cutting-edge molecular biology with circuit-level neuroscience to explore how experiences are encoded in the brain over time. While we know that memories are supported by distinct short-term and long-term systems, her research probes what differentiates these forms of storage at the cellular and molecular level, and how long-lasting memories persist despite the constant turnover of the brain’s components. By identifying the mechanisms that allow memories to endure—or that cause them to fail—her work opens new possibilities for slowing memory loss and developing more effective treatments for neurodegenerative disease.

If you were starting out your career today, what scientific problem would you most want to solve?

If I were beginning my career today, I would be drawn to studying how the auditory system analyzes the world of sound as we speak, listen to music, and experience other meaningful events in our auditory environment.

Such an interest would naturally extend to understanding how auditory brain circuits integrate with other sensory systems, making possible the rich experiences we enjoy at the opera, in the concert hall, and in other settings where sound and vision contribute to the full enjoyment of being alive.

Much remains to be discovered about how the brain’s circuits achieve this remarkable integration of sound and vision.

After a lifetime in the field, what still surprises you about the brain?

In addition to new concepts and ideas, the development of new technology has always been critical in advancing our scientific understanding of the world and ourselves. We are now entering a particularly interesting period with the emergence of artificial intelligence, which is already providing new ways to analyze complex data and to think about the brain and its functions.

It is still too early to judge the full significance of artificial intelligence, and caution is warranted. In neuroscience, however, it clearly opens many new avenues for research on both the normal and diseased brain. AI offers powerful approaches for uncovering patterns that would otherwise remain hidden.

It is also noteworthy that the influence runs in both directions: I have been told by researchers in artificial intelligence that studies of neural circuits have, in turn, inspired some of the concepts underlying modern AI systems.