One of the world’s leading experts in the neurobiology of emotion, Dr. LeDoux has garnered many accolades for his basic research into how the brain processes fear. Using clever conditioning experiments, he and his colleagues have been able to show that a small almond sized brain structure called the amygdala is responsible for processing fear in the brain. His research has also shown that other areas of the brain associated with higher reasoning and cognition inhibit emotional responses such as fear. I recently spoke with Dr. LeDoux about his research and his perspectives on emotion.
“Many of the anxiety disorders are fear related, panic, Post Traumatic Stress Disorder, phobia and so forth. I think we are studying an emotion that has an important significance for human life.”
BC: How did you come to study emotion?
JL: This could take up the whole interview. I have two degrees in business, and I wasn’t really interested in what I was doing. I just kept getting degrees because I didn’t know what else to do. I took a course on motivation and learning that a professor was giving at the time and I fell in love with brain research. I decided that’s what I wanted to do. So I went to graduate school in neuroscience and psychology studying the interface between the two. I got involved in some work involving split-brain patients, left right hemispheres and all that stuff. One of the experiments we did as part of that work was looking at what happens to the side of the brain that can speak, when you put information into the other hemisphere. We would put emotional information into the hemisphere that couldn’t talk and then we’d ask the talking side how it felt about it. Even though the talking side could not tell us what the stimulus was, because it didn’t see it, it got the emotional information. So it had a feeling or some sense of what was on the other side of the brain whether it was good or bad, but not what was over there. That seemed pretty interesting to me and I decided I wanted to try and figure out how emotions and stimuli are processed and their emotional significance so I started doing work on that.
BC: How did you make the transition from clinical studies on humans to basic research on animals?
JL: At the time, which was the late 70’s, there weren’t techniques for studying the human brain with much precision, so I decided the only way to pin down exactly how the brain was processing emotional information was to pursue this in an animal model.
BC: Which guides your basic research more, the desire to know the answer or the ability to acquire the answer to a scientific question?
JL: I think that it’s always a combination. There are some things that people do because they are taught how to do a technique, which is sometimes the case if you are trained in a more biological area where you can map out a transmitter in the brain or record some neuron. The ability to do that may drive the research, but if you are interested in more global functions of the brain, then hopefully you are pursuing the question of how those functions operate, rather than pursuing some technique. At the same time, the only way you can ask questions about things like how emotions work is to have a behavioral technique. There may be things we would like to know about emotion that we cannot ask because we don’t have a good behavioral model for it. I’m often asked why do I study fear instead of love or joy or something nice. The answer is that life is short. You can do one thing in detail or you can do a lot of things superficially. The other part of the answer is that the techniques for studying fear are simply better than the techniques for studying just about any other emotion.
“We are still studying emotional behavior but we are trying to understand the plasticity of the circuits that underlie that behavior.”
BC: In terms of positive emotions, do you think we will find anything as localized as what we’ve discovered about fear in the amygdala?
JL: The trick is really to have a task that allows you to ask the question with fear conditioning. You have a stimulus and a response, and you can see how they connect up in the brain. For other kinds of behaviors, it’s sometimes not clear what the stimulus is, or the response is more variable. It’s been less convenient to study those. I’m not sure if other systems will be less localized or if it will just be harder to figure out what the localization is.
BC: What do you fear the most?
JL: Snakes have always been my biggest fear. I grew up in a small town in Louisiana where there were lots of snakes, and I never cottoned up to them.
BC: Do you have a desire to study the other emotions?
JL: Not for the sake of simply studying another emotion. I think there is still a lot that needs to be done in the area that we are working on. There are many different versions of what we do, so I could probably, and often do, wear the hat of someone who studies memory as well as someone who studies emotion. As we fuse these two areas we try to understand in more detail how at the level of cells and synapses emotional memory is formed. We are getting into the molecular mechanisms of plasticity in the fear circuit,so I think there is no end to what we can do within this system. There is plenty of work to keep me occupied for many years to come. Maybe at some point I’ll get tired of always working on fear, but I think it’s a good emotion to work on because it has such important clinical significance. Many of the anxiety disorders are fear related — panic, Post Traumatic Stress Disorder, phobia and so forth. I think we are studying an emotion that has an important significance for human life.
BC: What ideas are you most enthusiastic about right now in your studies?
JL: I think the work in the areas of learning and memory right now. We are still studying emotional behavior but we are trying to understand the plasticity of the circuits that underlie that behavior. We are working on trying to identify what kinds of changes take place molecularly in terms of protein synthesis and perhaps even gene induction but we don’t have any real findings there yet. It’s just the direction we are going in.
“We can’t just deal with the cognitive brain; we have to deal with the emotional brain as well.”
BC: Do you ever speculate on the consequences of figuring those mechanisms out?
JL: Well one implication is that it might become easier to develop drugs that could be easily targeted to specific brain systems involved in specific emotions. For example, if we could develop some drug that could target the amygdala because of some gene that is found only in the amygdala. When you take the drug the gene makes a protein that would interact with the drug to turn it from an inactive to an active state and since that gene is only present in the amygdala, only the amygdala would respond to the drug and you would eliminate all the side effects. But that’s science fiction.
BC: What about the increased interest in Emotional Intelligence and the re-working of our existing theories of education to included emotional responses?
JL: Well I think that it is almost self evident now that it is out there. People like Howard Gardner have been saying this sort of thing for a long time and Dan Goldman’s book sort of struck a chord in the public’s mind as well. We can’t just deal with the cognitive brain; we have to deal with the emotional brain as well. I think it’s certainly true. How far you can take it beyond that in terms of applying what we know about brain mechanisms of emotion to the classroom is still up in the air. A lot of the attempts to relate brain mechanism to classroom education are really superficial. We simply don’t know enough about how the brain develops and what develops when and how it all works in order to take a flying stab at something as important as education. There’s a chance you might be wrong.
I don’t mean we should ignore the brain, but I don’t think we have the information we need for policy making. We don’t know enough. For example, we know a lot about how fear works, but should we then generalize from fear to the broader concept of emotion? And apply that to the classroom? I’m not sure. We certainly don’t know much at all about how the amygdala develops in infancy. There has been very little developmental work on the amygdala at all in any animal, and probably almost nothing is known in the human brain. So to say that on the basis of knowing anything about synapses in any part of the brain and how that relates to education, I think that is still a leap. We don’t know whether synapses are even the critical measure that needs to be addressed. You can measure brain development in terms of metabolism, number of synapses, myelination of nerves, cell density, on and on. You get different answers dependent upon what you measure and that’s a complication. Because if you use number of synapses you will come up with a later maturational date than if you use number of neurons. Neurons are there before synapses.
BC: How much do you think scientists need to be better at promoting science? Do people need to be better at understanding science or do the scientists need to get better at translating?
JL: There seem to be an awful lot of scientists now getting into the business of making science available. A tremendous number of books come out each year now by scientists. I guess you could say there is variable quality in the ability to communicate, but people are making an effort. The public seems to be buying the books, so I think it’s a symbiotic relationship that’s moving foreword.
BC: What books are you reading both scientific and otherwise?
JL: Right now I’m reading the Alienist. Its about turn of the century New York. Psychiatry was not a very popular field then in fact it probably didn’t even exist, and there’s a guy who is a practicing physician and pathologist who has gotten involved in a mass murder. So they are trying to solve the murder on the basis of criminal psychology. There is a lot of historical information about New York at the turn of the century and a bit about psychology, William James and other things. So it is sort of interestin