Eric Kandel was attracted to the science of the human brain due to his interest in psychotherapy. Where, he wondered, are the Freudian id, ego, and superego located? He soon discovered that even the simplest mental processes were mysteries at the time. So he scaled back his ambitions and began studying the Aplysia, a species of sea slug with the largest neurons of any living thing. After years of careful research, he documented the neurological mechanisms by which our memories are stored. His efforts won him a Nobel Prize. Kandel’s book “In Search of Memory: The Emergence of a New Science of Mind” is a poignant personal journey through the science and subjective experience of memory. It was recently made into a prize-winning documentary of the same name.
Brain World: How did you feel when you first saw the film?
Eric Kandel: Extremely uncomfortable. One doesn’t recognize oneself. I’m a fairly happy guy, but the idea that I’m always laughing this loud, braying laugh! Or that I’m so brazen as to barge into people’s apartments. But [filmmaker] Petra Singer is an artist too, and she picks up the details she needs to tell the story she wants to be told.
BW: “In Search of Memory” is successful, both as a book and a film, in part because of your personality. Were you aware, when you wrote the book, that weaving the narrative of your life in with the science research would work so well?
EK: I think the success of the first book was keeping it stitched together. When I heard that I’d won the Nobel Prize, they asked for two things — a speech and an autobiographical essay. I hadn’t discussed my background much before that, but I dug into it and I found it very rewarding.
BW: When you first began researching the brain, what surprised you most?
EK: How easy it is to produce changes in the strength of synaptic connections. When I began to work with the nervous system, the ease with which I could produce changes was astonishing. The idea that the brain has plasticity as one of its identifying characteristics was completely new. And two other things: That long-term memory altered the expression of genes amazed me, and how easy it is to turn genes on through learning, triggering the growth of new synaptic connections, which the film displays very nicely. That was a breathtaking finding for me.
BW: How does long-term memory affect genes?
EK: Well, the signals that step up long-term memory within the neuron move into the nucleus, and there they activate genes that give rise to the growth of new synaptic connections. When I was working on this, the general thought was that genes control behavior: You have one mutation, you get schizophrenia; you have another, you get depression. The fact that the genes were also the servants of the environment — that they responded to external stimuli — was not known. When I first showed it, people were confused by what it meant. I mean, learning does not produce a mutation. You can alter the level at which a gene functions without altering its structure.
BW: What, if anything, is surprising you now?
EK: Well, I’m interested in the mechanisms whereby which memory is perpetuated, and how one remembers something for the rest of one’s life. We’ve identified a regulator of protein synthesis of the synapse that is responsible in maintaining memory over very long periods of time; in principle, over a lifetime.
BW: So how has your neurobiological understanding of the brain affected how you live your life?
EK: Oh, it hasn’t affected the way I live my life. It’s affected the way I think about the world. I think of psychotherapy in a different way, and education in a different way. What’s interesting is, we think of the brain research as being relevant to brain processes — schizophrenia, obsessive-compulsiveness, aging, development — but many people see it as a font of new knowledge about things like decision-making: why people prefer a short-term gain that is more likely, over a much greater long-term gain that is less likely. Animals have the same thing, and we’re beginning to figure out what’s going on in the brain under those circumstances. Art is another example: how our insight into perception, emotion, and empathy gives us new insight into art — or philosophy. All these disciplines that used to be independent of brain science are likely to be influenced by it over the next 30 years. I think that is a remarkable change in our lifetime.
BW: The film shows you swimming, which I know you try to do daily. Neuroscience has documented the advantages of exercise in facilitating learning and staving off dementia and Alzheimer’s. Have you always exercised, or do you exercise for the cognitive benefits?
EK: Well, I was captain of the high school track team. I find swimming psychotherapeutic, and even if I do it for only a short period of time, I feel better. Obviously, now I realize it’s good for me, but I do it because I like it. I now recommend to other people that they do it, because I know it’s beneficial.
BW: Do you think the neuroscientific community should exert more influence in public policy?
EK: I certainly think so. The Society for Neuroscience is doing that. I mean, this is not unique to neuroscience. We live in a technologically sophisticated universe, and in a democratic society people have to make policy decisions, sometimes requiring knowledge that they don’t have. One of the nice things that come out of the book and the film is that people learn something.