Wednesday, July 25, 2007

Joseph LeDoux's heavy mental

The neuroscientist explains how music, emotion and memory shape our identities -- and why he has donned a Stratocaster to keep the brain rollin' all night long.
By Jonathan Cott and Karen Rester
Jul. 25, 2007

In May at Madison Square Garden, an unknown, unsigned rock band began to play. It was only its fourth show since forming in the fall of 2006. Granted, its last show had sold out, but that was in the basement of the Cornelia Street Cafe in New York, which holds about 30 people. The Amygdaloids were staring at a crowd of 10,000, a big leap for a band that had yet to release, well, anything. Then something phenomenal happened. In the midst of its signature song, "All in a Nut," an inspired kid in the audience began leaping out of his seat, igniting a wave that went around the entire 200,000-square-foot arena. The band members were stunned; they had never seen anything like it.
All right, the occasion wasn't a concert but a graduation ceremony for 10,000 students in the New York University College of Arts and Science. Still, this was no ordinary club band hired to entertain the students. The Amygdaloids are made up of four scientists from NYU whose chief singer and songwriter is Joseph LeDoux. Earlier in the evening, LeDeoux had given the faculty address. Although one must ask what kind of neuroscience professor invokes Tennessee Williams and surrealist filmmaker Luis Buñuel to send a graduating class out into the world, then picks up his white Stratocaster and launches into a rock ballad about the amygdala, that almond-shaped "nut" in the brain that processes primitive emotions like fear, love, hate and anger: "Why do we feel so afraid/ Don't have to look very far/ Don't get stuck in a rut/ Don't have to look very hard/ It's all in a nut, in your brain."
A much-lauded pioneer in his field, the 58-year-old LeDoux, who is the Henry and Lucy Moses Professor of Science at NYU's Center for Neural Science as well as director of the Center for the Neuroscience of Fear and Anxiety, is perhaps used to being greeted by scientists, students and brain buffs alike with, as the New York Times put it, "enthusiasm usually reserved for rock stars."
Back in the '70s, when neuroscientists considered emotion too subjective for serious research, LeDoux made it the focus of his work, tracing the pathway in a rat's brain that leads to the fear response. The implications of this finding launched his career. His two highly praised books, "The Emotional Brain" and "Synaptic Self," look to the amygdala and to the brain's synapses, respectively, to understand how neural processes shape who we are, what we think, feel and remember. More specifically, LeDoux asks how the brain creates and remembers emotion, whether synaptic changes determine mental illness and how traumatic memories can be controlled and even erased.
Which prompts the question: What is LeDoux doing with a Stratocaster, anyway? Salon recently sat down with LeDoux in his NYU office, where he spoke to us as enthusiastically about the Amygdaloids and his love of music as he did about the amygdala itself and the extraordinary ways memory and emotion shape our identities.
What got you into using music to convey your ideas about the brain?
To be perfectly honest, I just love music, and when we wrote our first song, "Mind Body Problem," last November, I thought this could be our genre, especially after Newsday dubbed us "heavy mental." I think using music to teach students about the brain has a lot of potential. But right now we're just having a lot of fun playing.
How did all of you scientists find time to leave your labs and start jamming together?
Tyler Volk and I met because we both wrote science books for lay readers. Over dinner we discovered we both played guitar, so we started jamming together, mostly playing '60s classic rock and rock blues. We'd get together every month or so at one of our places for a couple of hours of guitar and then go to dinner, where the discussion often drifted into fantasies about having a band between discussions of the self and consciousness. When the holidays came around in 2005, we played some of our favorites at my lab party, like "Crossroads," "All Along the Watchtower" and "It's All Over Now, Baby Blue." After the party, Daniela Schiller, a postdoc who works with me, came up and said she plays drums and would love to jam with us. In the summer of 2006, I got an invitation to speak at a science event at a bar in Brooklyn [the Secret Science Club]. They said there would some entertainment afterward and I volunteered the three of us. At that point we felt we needed a bass player. It turned out that Daniela's research assistant, Nina Curely, had been taking bass lessons, so we invited her to join us. We practiced a few times and on November 1st the Amygdaloids had their first show. We're excited that our first CD will be released in the fall of 2007. [Listen to four songs here.]
What's the earliest rock 'n' roll song that you remember?
In my faculty address for NYU, I said I often think about the past in terms of the songs I was listening to at the time; it's how I categorize my life episodes. The earliest song I remember is "Love Me Tender."
How old were you at the time?
I was probably 7. There was a little diner a block from my parents' butcher store. I was in love with the waitress and she was in love with this tough guy who wore a leather jacket and rode a motorcycle in our town. And she used to sing "Love Me Tender" all the time. I went there every day and ordered a Coke and sort of stared at her.
After college you had a brief stint in a group called Cerebellum and the Medullas. What made you choose such a brainy name?
I liked the name. I remembered it from high school biology.
You weren't studying neuroscience at the time?
No, I was doing marketing. I didn't know anything about the brain. That was just out of the blue.
Daniel Levitin, who runs the Laboratory for Music Perception, Cognition and Expertise at McGill University, and who is the author of the book "This Is Your Brain on Music," has a rock group called the Diminished Faculties, composed entirely of professors and students at McGill. What is it with you neuroscientists and rock 'n' roll?
I don't know; they're coming out of the woodworks. We accidentally received an e-mail from someone in that group. It was after an article about us appeared in the New York Times. The e-mail said something like, "All right, we gotta get going. Look at what these guys are doing! We need to invite them up here and show them who's boss."
Most memories degrade and distort with time; why are music memories so sharply encoded?
I know from my own experience that it's a very powerful way to remember things. I've found that in the short time we've been playing music we can convey the gist of a concept with a three-minute song that we'd need a chapter for in a book and many, many hours of painstaking work to get across. Then people read it and they forget everything. But you can just sing the line, "An emotional brain is a hard thing to tame," which captures the essence of the concept, and people remember it.
It's very hard to erase memories of a piece of music, isn't it, unless a person suffers something like retrograde memory loss. Then I suspect the person wouldn't remember the songs from the period he or she has lost.
It would be interesting to hook that person up to some kind of physiological machine and see if they had autonomic responses to those songs even though they don't consciously remember them. There's a chance that they're in your brain implicitly but you just can't access them.
Neuroscientist Steven Pinker called music "auditory cheesecake," meaning music is pleasurable but of no evolutionary importance. If music isn't necessary for human survival, why has it appeared in every culture we know about?
There's a lot of important rhythmic activity in nature, whether it's the circadian rhythm of the daily cycle, the seasonal rhythm, the monthly rhythms. Just look at the human body. I mean, so much of what a body does is based on rhythm. Take the heart rhythms, the brain rhythms. Music is one expression of biological rhythm. That's why pleasing music has a kind of symmetry and rhythm to it that discordant music doesn't. I'm not sure he's right about music not having evolutionary importance.
Maybe the secret to music's power -- its ability to trigger memory and emotion in the listener -- is the fact that emotion and memory are what inspire it.
Yes, absolutely. Love songs, hate songs, blues. It's all about those big experiences in life. When words matter it's because the listener can relate to either the pain or the joy with the singer. So I think that's true. A lot of what inspires music is emotion and your memory of those emotions and your anticipation about future emotions.
Could there be something like mirror neurons at play, which fire both when a person observes an action and when they perform the action themselves.
That's an interesting idea. I think that's probably true, especially at a concert. You're watching the musician on stage and your brain is locking in with what he or she is doing, and so I think there is probably a lot of mirroring going on.
So if a musician's neural pattern is transferred to the listener's brain, perhaps the reason it's so strongly encoded is that by listening to it repeatedly the pathway becomes stronger and stronger, just as with a memory that you recall repeatedly.
I think it's more than repetition. I can imagine at a concert where you've got the musician up onstage, and there's a lot of intensity and the music is loud and driving and the crowd is swaying and the guy is dancing around onstage. There's a lot of stuff going on. Emotional upheaval like that is very good at storing memories. There's a very famous study from Columbia in the '60s, where they took people and gave them a shot of adrenaline, which revved them up, and then put them into a room of sad people, happy people or neutral people. If you had the injection you came out feeling the mood of the room you were in. Revving you up like that and putting you into a particular context creates emotions that are appropriate to that context. Your memories will automatically be stored more strongly because of the emotional arousal.
Researchers from the Montreal Neurological Institute took PET scans of musicians' brains while they listened to pieces of music that "turned them on." Music activated similar neural systems of reward and emotion as those stimulated by sex, food and addictive drugs. It's amazing that all of these things press the same button -- drugs, sex, music.
But it has to be music that you like; it's a reward. There are certain things in the world that are rewarding, like food and sex, and then there are things we attach to those rewards through experiences that can become rewards in themselves -- what we call conditioned or learned rewards. If you have a positive experience and a song is playing, then that positive experience attaches to that song and the song itself becomes a reward.
You write about how our brain synapses change through experience, what is called synaptic plasticity. And, indeed, research continues to demonstrate how amazingly plastic the brain is. Even as our cognitive abilities like memory degenerate over time, we can strengthen them through brain exercises. What do you envision happening in the future as scientists learn how to more expertly manipulate this plasticity?
We manipulate plasticity all the time. Each time you go to a nice restaurant for dinner to celebrate a special occasion, a birthday or anniversary, you are creating a situation in which the memory of the event will not be ordinary and fleeting. Much of psychotherapy is about plasticity -- getting patients to learn new ways to cope with challenges. But then there's also drugs. Lots of companies are working on memory enhancers, mainly to be used to help people with memory disorders. But drugs already exist that can enhance memory formation, and these are being used to help people with phobias learn fear reduction through exposure to fear-arousing stimuli. There are much-publicized debates about this coming out of the new field of neuroethics, about drugs that enhance learning and memory, since obviously such drugs might also be used to improve "normal" memory.
Speaking of memory, what did you think of "Eternal Sunshine of the Spotless Mind"?
I've said they ripped off our research.
I didn't really mean that in a negative way. We published a study in 2000 on this exact topic, which started this whole memory-erasure field. The film, which came out in 2004, described exactly what we were doing. We would activate a memory and then zap it. We were zapping it with a chemical, a shot of anisomycin; they zapped it with a machine.
Did they ever contact you?
Someone ran into Michel Gondry [the film's director] and asked him whether he was aware of the similarity to our study and he said that it had influenced him. I mean, our work is out there, it's in the world.
You pointed out one way of reconciling science and faith in "Synaptic Self," writing that "a spiritual view of the self doesn't have to be completely incompatible with a biological one," because even the nonmaterial soul depends on brain functions. Can you elaborate on this? What are the implications of this for you personally?
The idea that a spiritual view is not incompatible with a synaptic view of the self was important to me when I wrote "Synaptic Self" because I wanted to reassure anyone who got to that point in the book, who might be having reservations for reasons of faith, that they should read on. That is, I wasn't using brain research to try to dismantle faith. I had something more inclusive in mind. Personally, I'm somewhere between an atheist and an agnostic, so it wasn't about a deep internal struggle. But do I really know this? Probably not. Many of our motivations are unconscious. Given that I was quite religious as a young boy, maybe I do have some deeply internalized struggle going on.
You've said the implicit or unconscious aspects of the self play an essential role in shaping who we are and explaining why we do what we do. You've also said, "An understanding of the mystery of personality crucially depends on figuring out the unconscious functions of the brain." How is personality shaped at the unconscious level? What's something that really surprised you about this process?
I've long believed that much of who we are is due to unconscious processes. This goes back to my Ph.D. thesis work in spilt-brain patients, done with my advisor, Mike Gazzaniga. In these patients, the two sides of the brain are separated to control epilepsy. From the point of view of each side, behaviors produced by the other side are behaviors that are unconsciously produced. So we did lots of work trying to understand how the left hemisphere, which has language and can be communicated with, dealt with behaviors produced by the right hemisphere. The surprising thing was how seamlessly the left hemisphere adopted these behaviors as its own, as if it had produced them.
This led Gazzaniga and me to propose that much of human behavior is like this -- produced by unconscious systems. Consciousness then makes sense of it all by telling a story. Gazzaniga went on to pursue the nature of interpreter functions of consciousness and turned to trying to understand the unconscious control of emotional behavior. That's how I got interested in the unconscious aspects of mind. If you think about it, the enduring features of mind and behavior that define our personality are not things we consciously control. We are simply that way, and it can be hard to change those things because they are unconsciously controlled.
You've said the big question that brain research should be asking is: What makes us who we are? As biologists turn up evidence that animals can exhibit emotions and patterns of cognition that were once considered to be strictly human, Descartes' dictum, "I think, therefore I am," loses its force. Do you agree? If so, how does this affect your approach to "the big brain question"?
I don't buy this. Sure, animals have emotional behavior and can solve problems using cognitive capacities. However, a key thing about human cognition is the way language shapes it. Language allows us to classify and categorize the world instantaneously on the basis of words. A single word can imply so much -- think of how much information is carried by the contrast between the words America and Islam. And syntax allows us to rapidly conceptualize who is doing what to whom and to convey this to others. Also, the areas of the brain most involved in human cognition are in the prefrontal cortex, which has areas that are more elaborate in humans than other primates and nonexistent in other mammals. I do agree that much of the human brain can be understood in terms of animal brains -- very basic emotions like fear are a good example. But when it comes to higher cognition I believe the human brain stands out.
You and others have indicated that solving the origin of the self is a binding problem. You explain that there are a number of brain systems running in parallel and these systems bind together to give rise to what we perceive as the self, as a "coherent personality." How does this binding happen? And is the self really just an unexpected byproduct of synaptic plasticity? In other words, are the things humans value most in the world -- thought, creativity, beliefs, love, happiness, family -- are these just the happy accidents of an evolving brain?
The fact is that there are many different systems in the brain -- perceptual, emotional, motivational, cognitive and so on. And within each of these broad categories there are lots of divisions. All of these run in parallel. Neuroscience has learned a tremendous amount about how systems and brain areas work. But our self, our personality, is not just the sum total of our brain systems. Our self can be thought of as a particular configuration of functional activity occurring in many systems at once. These configurations are determined by our genetically based wiring and by the experiences we have as we go through life. When it comes to mental life and behavior, nature and nurture are not two different things but two ways of doing the same thing: wiring our synapses.
For example, each emotional experience you have will subtly change the wiring in many systems. If you have lots of fearful, stressful experiences, synapses in these various systems will be wired with a fear bias. Lots of positive experiences will have different biasing effects. These biases may be especially important in early life when the brain's wiring is up for grabs. Once developed, the biases will make one susceptive to certain kinds of thoughts or feelings, or make one seek out certain kinds of experiences. It is well known that people with phobias are especially sensitive to environmental stimuli that are related to their fears, and depressed people seize on negative information.
I don't think that the things we cherish are accidents of an evolving brain, as you put it in the question, but instead are a consequence of the way genes and experiences wire our brains. The good news is that each experience rewires the brain. We have the capacity to change, but the more we change earlier, the easier it may be to shift the bias. The subtitle of "Synaptic Self" is: "How Our Brains Become Who We Are." This was meant as a way of emphasizing the importance of learning, since there has been a big emphasis lately in neuroscience on genes. The world will be a better place if we adhere to the idea that change is possible. I wish "The Sopranos" hadn't ended so fatalistically.
In "Synaptic Self" you've come up with some interesting ways of thinking about consciousness. What do you think are the key brain mechanisms that underlie consciousness? And how close are we to the final answer?
Consciousness is important and immensely interesting. Lots of progress has been made conceptually and empirically. My own view, which is shared by many, is that it has something to do with the unique human capacity for language and also with the newly evolved prefrontal cortex and its capacity for working memory. These ideas are described in my books, so I won't go into detail here. The key thing for me is that even if we solved the problem of consciousness we wouldn't understand how our brains make us who we are. We wouldn't know why people develop mental disorders or start wars. We wouldn't know about the fundamental motives that drive human behavior. Even very complex motives like the desire to succeed or to obtain power are not simple reflections of consciousness. Dick Cheney probably thinks he's a good guy.
Where is your work headed?
One big question is how the brain controls not just emotional reactions but actions. For instance, with the fear response you can't stay frozen in fear. Eventually you have to take action -- fight back, run away. This transition from reaction to action is a key to the brain mechanisms, underlying something that therapists have known for a while -- that active coping strategies are more beneficial than passive coping. I'm also very intrigued with the problem of emotional development, with the idea that we build up emotional biases through experience and that early life is especially important. If true, it would mean that we should be teaching kids ways to control stress at an early age, maybe even as part of their educational training. Because of my belief in the importance of early emotions, I've made emotional development the main focus of the new Emotional Brain Institute I've started.
What will the institute be dealing with?
Together with Harold Koplewicz, a professor of child and adolescent psychiatry at NYU, and the support of NYU's administration, this institute will be dedicated to the study of emotions, especially fear and anxiety, in young brains -- in both animals and children. We want to start teaching kids how to regulate their emotions. I also want to make emotion a university-wide integrative topic at NYU that can unify the arts and humanities (literature, history, visual and performing arts) and the applied disciplines (business, law) with the sciences. These are big goals for the Emotional Brain Institute, but I think we can do it.
-- By Jonathan Cott and Karen Rester