>> rose: welcome to the broadcast. tonight, a charlie rose special edition. if the seventh episode of our brain series, we look at the emotional brain. >> we're talking, as you outlined so well, about emotions. these subjective experiences, states of preparedness in response to specific people, situations as we are gathered together two great anticipation of pleasure. >> rose: right. >> for this round table that we're going to have tonight. and emotions are designed to enhance our capability for pleasure and decrease our exposure to pain. >> rose: the seventh episode of the charlie rose brain series underwritten by the simons foundation coming up.

captioning sponsored by rose communications this is charlie rose. >> rose: tonight we continue our exploration of the most complex object in the known universe: the human brain. this evening, the first of two conversations on the science of emotions. everyone is familiar with such feelings as joy, anger, excitement, and envy. but science is just beginning to understand where these emotions come from and how they control

our behavior. this evening, we will focus on how the brain regulates pleasure and reward. the pleasure and reward system involves several different brain regions that communicate using chemical signals called neurotransmitters. the circuit helps to repeat the behaviors that make us happy while avoiding those that make us miserable. but as any adult knows, pleasure is not always good for you. tonight, we'll also explore a particularly dangerous form of pleasure seeking, addiction. long considered to be a moral weakness air, diction is now understood to be a biological disease. finally, we will explore the role that emotions play in decision making and social interaction. next month, in part two of the emotional brain, we will turn our focus to negative emotions such as fear and anxiety. joining us tonight, a group of scientists who have devoted their lives to understanding the emotional brain. daniel salzman, he studies how

the brains assigns an emotional value to the information it receives from the five senses. he is an assistant professor of psychiatry and neuroscience at columbia university. wolfram schultz, he studies how the brain's reward systems affect decision making and learning. he is a professor of neuroscience at cambridge university and a fellow of the royal society. nora volkow. her research into addiction helps us understand drug abuse as a disease rather than a moral weakness. she is a director of the national institute of drug abuse in washington, d.c. eric nestler. through research on mice, his work has illuminated the molecular basis of drug addiction. he is chairman of the department of neuroscience and director of the brain institute at mount sinai medical center here in new york. and once again, my co-host is dr. eric kandel. he is a nobel laureate, as you know by now, also a professor at

columbia university and a howard hughes medical investigator and, as you also know, a great friend of this series and the man who has helped us understand this miraculousar gan. welcome. >> mesh pleasure to be here, as ways. >> rose: so as we go through this. as we have gone from understanding visual perception and understanding the developing brain and the aging brain. and now we come to emotion. tell me what we mean and how does the brain connect to emotion? >> well,s always, you outlined it extremely well. emotions are a family of subjective experiences, states of readiness that we all experience in response to significant people and situations in our lives and emotion are designed to enhance our opportunity for happiness and decrease our exposure to misery. it turns out that the first

person to really consider the biology of emotion is, in fact, our friend charles darwin. the greatest biologist of all time. in the course of his classic work on evolution, he realized that emotion is an extremely important subjective state that is universal. it's shared by people in all cultures and it's shared by all animals. and this made him focus on the fact that emotions are part of a basic approach avoidance system that is designed, as you indicated, to enhance our opportunity for feeling good and decrease our opportunity for feeling miserable. >> rose: and here is the book "charles darwin, the expression of the emotions in man and animal," published in 1872. >> a remarkable book. and in this book, he points out that in addition to emotions being of personal value that

enriches our mental life, emotions also have a social function. they convey emotion from one person to another. for example, they're important in mate selection. darwin pointed out that the social aspect of emotion communicated through facial expression. this book came out in 1872. two years earlier a modification in printing occurred that allowed you to reproduce photographs inexpensively in print. and this book is one of the first books that is literally filled with photographs of various kinds of people in various emotional states. and darwin was particularly interested in children. he studied his own children very carefully, was curious about their behavior. and it struck him that children express emotions in a particularly pure and powerful form. and here we see happiness and

sadness in a child. and this, of course, raises the question how do we classify emotion? and darwin implied-- and we now have very good reason to believe-- that we classify them along two dimensions. valance and intensity. here we have valance. so there are anywhere from six to seven emotions that range from happiness that his approach sprays, disgust, contempt, anger fare and sadness. for each of these there are degrees of intensity. so you can be happy slightly or deliriously happy. and this is true for each of the emotions. today we're considering positive emotion and there are four structures that are important here. the amygdala, which orchestrates emotion. the try yay tum that gets recrueted for habit and also

drug addiction. striatum. there is cognitive control of emotion, whether it's appropriate to particular a particular emotional response in this context versus another that is mediated by a high level structure called the pre-frontal cortex and controls these two other structures, the amygdala and striatum. all of them are influenced by a pleasure system in the brain. now one of the striking things about this circuit for emotion and particularly the dopamine pathway is it is involved in a number of diseases states. so it's disturbed in schizophrenia, in parkinson's disease, and it also cooperative in addictive disorders. so drug use such as cocaine and heroine hijack the system.

and one of the great insights that you'll hear is exactly how this occurs. these drugs simulate the activation of this system. they take it over. >> are there stages of addiction? >> there are several well-defined stages of addiction too begin with, there's the addictive process itself whereby as you outlined people begin to experience of an addictive drug, get the pleasure of addiction as the system hijack it is system and they focus on getting the drug and on all other aspects of their lives. they neglect their families and health. knowing they're destroying themselves they continue to use the drug. number two, as they continue to use it think become tolerant.

so the doses they initially use to give them a high is no longer effective they need to go to higher doseage. and the striatum, which gets recreted but something like cocaine no longer responds once the person has used cocaine for some time. and one of the most tragic aspects of addiction is the third face phase, always the possibility of relapse. so even if the person gives up drugs for weeks, months, even years, exposure to the site of the drug, the smell of the drug, walking a street in which they used to buy the drug or bumping into people that use the drug brings a tremendous urge to use the drug back to them. as a result of this, very, very easy for people to relapse and using these drugs again. this is why we realize that

addiction is a life long disease it can never be cured, people can be helped with it but they have to be monitored throughout their whole life. and you would think a process like this is extremely difficult to study. the fact is, we've made quite good progress in understanding it through two quite different avenues. first of all, we can study it in people using imaging techniques. and nora volkow has pioneered this. we can study it in mice and flies. so there are a number of approaches to studying addiction. >> rose: why are we devoting emotion into two parts? it's a nice neat division between pleasure and reward and fear and anxiety but why this

division? >> it's a very rich subject and there are different diseases associated with positive and negative emotion. we spoke about the positive emotion. addiction is the prototip i can example that cooperate it is positive emotion. we now have a large number of veterans coming from iraq that suffer from excessive negative emotion. a memory of seeing a friend get killed in battle right next to them. of seeing wounded people. of having shelves shells explode around them. these people come back with post-traumatic stress disorder which is a remembrance of a frightening episode. in the next program we'll discuss the role of the amygdala in both of negative and positive emotions. and the fact that we can now treat post-traumatic stress disorder in an effective way and

we can discuss the treatment of the disorder. >> rose: all right, here is our first of two hours on emotion in which we look at pleasure and reward with our panel. tell me about emotions and the variety of emotions. >> this is the challenge. when you move on to mental processes and study mental processes that can vary in many dementions, an emotion is a process of that. the question then becomes for neuroscientists is how do you take different emotions such as disgust, anger, joy, happiness and how do you map them into brain circuits. so that's the starting point. all of rur psychologists at the beginning in order to understand how to map these linguistic terms into processes that might actually be represented in the brain. there's at least two components in emotion that are critical for

understanding in that regard and one is that everyone knows what an emotional experience is like but if you think about it for a minute has both a conscious component and an unconscious component. what does it mean? it means there are certain aspects of our emotional responses that are automatic. that are happening without us thinking about it and there have to be brain systems operating below the level of our consciousness that execute those processes. at the same time we have conscious feelings of emotion and awareness of the emotions and we have to come up with ways of understanding how the brain could be then modulating emotion in a way that would influence our consciousness awareness. our conscious awareness of them. so that's one aspect of trying to understand emotions, to be able to understand the divide between conscious and unconscious processing in the brain. >> that's really a very interesting example, because maybe you can give a specific example of that. if you have a lion all of a sudden coming into this room, we would be prepared to run away before we specifically perceived that it's a lion.

so we have a physical response to it knowing we're in a dangerous situation before we even see what the specific nature of the threat is. >> it's not just that we want to flee, there's other responses. we'll start sweating a bit. so there's aspects of the response mediated by our nervous system that are automatic, happening below the level of consciousness and part of our emotional experience. for decades scientists have debated in a chicken-and-egg fashion which comes first, those physiological responses and response to stimuli or the consciousness... conscious awareness of that. so this is a big issue in terms of defining emotion bus there's another aspect of emotion that eric touched on a little bit earlier which is that debate our very rich language for describing emotions, you can actually map many aspects of these emotions on two two to axes. one has to do with how good or bad something is. the say are lens of the emotion. and the other has to do with the

intensity. so you can get excited in a fearful state or a happy state. so the valence is different but the intense city similar. so you can map map most emotions on to those two axes in both ways. you can reduce the emotional experience to those two axes in a useful way in terms of looking at brain systems. >> maybe you can take us through amatny of the emotional system. >> so we were talking about different aspects of emotion that need to be coordinated in the brain and the first slide is giving you a window on some of these key structures. this is a lateral view of the human brain. so you're... your cover of the brain is the veer ral cortex, you've seen that before in prior subjects and you've talked about the hippocampus buried in the medial temporal lobe. it's involved in learning and memory. eric mentioned earlier that the key coordinator of the emotion is the amygdala which sits just

anterior to the hippocampus there. the amygdala is thought to be a key coordinator of emotion because it sends projections both the subcortical structures, subcortical structures that modulate some of the different physiological responses we are discussing such as heart rate and how sweaty you are when you're nervous and things like that that are part of the automatic or unconscious aspect of emotional experience. at the same time, the amygdala also sends projections up to the cerebral cortex including a prominent projection up to the thinking part of the brain, the pre-frontal cortex which may well mediate exactly how emotion can influence different aspects of cognition. now, some of the other structures that have been mentioned already were dopamine neurons as well as the striatum which is another target of dopamine neurons and we'll be discussing all four of those structures throughout the show. now, emotion, of course, needs to be regulated and in the regulation of emotion, that's thought to happen in part by

communication that comes from the pre-frontal cortex back down to the amygdala as shown here. so these are the structures that we're going to be talking ant. and dopamine actually broadcasts its signal broadly throughout the cerebral cortex. so you can see here dopamine neurons which have very prominent projections up to the pre-frontal cortex, up to the striatum and nicely to the amygdala as well. so it's in a position to broadcast some kind of information and in particular we'll focus on the information related to rewards and reward prediction today to wide parts of the... wide aspects of the brain. >> rose: how do rewards come into this? >> well, i think rewards are a basic come needn't will lead in one way or another to emotions. so the standard view, of course, is rewards make you happy but in neuroscience we have a little bit wider view. so we think that rewards are basically all objects that make us produce approach behavior.

that we approach thabs we want to spend energy on. rewards make us learn things. then how did rewards enter neurobuy sglolg it's obviously a very general concept and even if you tried to scale it down a little bit with these examples, in the 1950s, there was a very famous experiment in a series of experiments in which they put small wires into the brains of little rats and the rats would push a lever to produce a current to their brain the current is so weak you wouldn't sense it as a tickle on your skin. and the rats would press the lever over and over and over again to just a v that stimulus inside their brain. not just anywhere, it was in particular parts of the brain where you have to do that. and then the rats... it was so strong this kind of approach behavior and this generating

power... behavior generating power, they would stop eating, they would stop drinking, they would stop having sex. they would basically die. actually, they would die if you would let them go on and stimulate. they wouldn't eat. >> rose: the pleasure was so great they would sacrifice everything. >> more pleasurable than anything else. remarkable set of experiments. >> amazing. absolutely amazing. that's it. >> just as an aside, peter millner who together with olds discovered this is is the husband of brenda miller. >> rose: brenda was here last time >> it may go beyond pleasure, though. it's not just pleasure, there's something about the stimulus that prompts you to repeat it again. >> rose: what would that be, snow >> i think that remains unknown. that's something that >> i think this is the reward predicted stimulus. the question was what brain systems are these. you can look at your electrode

and it was in the brain stem where it is quite... or in the midbrain where it's quite complicated to finding individual brain structures. and then came the revolution in neurotransmission, in chemical neurotransmitters in the '50s, '60s, '70s, a number of neurotransmitters were identified including one called dopamine. so dopamine is a chemical that serves a neurotransmitter and is released from neurons that have identified the anatomic positions in the brain. so the dopamine neurons projected to the preparental cortex, the amygdala and a few other brain structures, these the most important ones. it turned out that the manipulation of the dopamine neurotransmission by giving dopamine antagonists and other substances would modify reward-seeking behavior. and in particular it was found out like by people like roy wise and associates and other people

that the electrical stimulation for brain reward was partly related to the dopamine neurons. in fact stimulating the dopamine neurons meant the animal would repeat that electrical stimulation. it was like getting a reward. >> rose: tell us about addiction. >> at the essence, of course, of addiction is why do people take drugs? and they take drugs because they want to feel good. and drugs make you feel good. and they make you feel good because they hijack these reward systems. all of the drugs of abuse that we know that can make people... that increase dopamine in the pleasure centers of the brain and that is believed to actually be crucial for producing the rewarding effects and to ultimately lead to the changes that we saw in addiction. now, with imaging technologyings we can actually now go inside the brain of the people... of a person addicted to drugs and see what areas of the brain may be disrupted that could explain why is it that a person that's addicted to drugs can not

control the urge to take the drug even though they actually can tell you sometimes they are no longer even pleasurable anymore they were pleasurable initially but as they repeat the taking of the drugs, that pleasure becomes less and less and they start to take it not to get high but just to feel normal. so with imaging, for example, we can look inside the humane brain and see there you have a diagram that shows the same dopamine cells, normally you cannot look at them, you require an imaging technology that relies on activity and the way that you're going to be looking at how drugs increase dopamine in the following way. normally you have dopamine cells releases dopamine when you take a drug, for example. and dopamine sends this message by binding to the receptor. you take a rook active compound that binds to the same receptor as dopamine but can only bind when the receptor are not occupied by dopamine.

so that allows you to taken a image and then you bring the subject back and you test them when they are taking a drug like cocaine. cocaine interferes with dopamine removal from the space and those dopamine occupies all of the receptors in such a way that when you give them radioactive compounds the receptors are okay paid and it can no longer bind. so you see that decreasing activity which is really a function of the fact that the drugs are increasing dopamine. so you can now use exactly these technologies to go inside the brain of a person that's addicted and a person that's not addicted and to compare the brains when you give them a drug. and this is what you see there. for example, to the left is a placebo, a saline solution. and you see a lot of radioactivity in the center which is the striatum, which is where one of the main reward areas of the brain is. then you see the drug and you see the decreasing activity because dopamine went up. to the surprise of everybody, including us, when we gave it to

people that are addicted, we saw almost no signal. and this is antithet cal because if the drug is not so effect i have in increasing dopamine and we take drugs to feel good and that relates to increasing dopamine, then what is the lodge snick and what we found, actually, was very intriguing and very telling, but very malignant with the process of addiction. and it's something that wolf ham described many years ago which is once the brain learns that a certain stimulant produces reward it stops increasing dopamine with that stimulant and instead increases dopamine when there is a stimulant associated with it that predicts you're going to get reward. that's what we call conditioning and what pavlov described with his dog. the sound predicted to the animals... >> rose: the sound of the bell. >> exactly, yes. well, the same thing is happening in addiction. the people that are addicted to drugs are increasing dopamine when they see the needle, when

they see the person that they had drugs before, in the neighborhood where they actually have been. so look at the images in the next slide which actually show in the left people just looking at a nature video, a nature scene, and to the right these are cocaine abusers, the same cocaine abusers but now they are not looking to nature scenes, they are looking to a video that shows people taking cocaine. you see the radioactivity has gone down because dopamine goes up. so you see that stimulate increasing dopamine in the striatum and that is subjectively associated by these individuals with a tremendous desire to take the drug. and you can then start to understand why it's so very difficult to a person that is trying to stop drugs to go back to their environment. because everything reminds them of the drugs. everything is condition. so this is an automatic behavior that's going to resolve in the one thing of more drug. the wanting of more drug. >> it came up a few years ago when billboards were around

showing lines of white powder and a razor blade as a way to get people to stop doing cocaine. and we found that that stimulus provided an incredibly strong cue to remind people of these memories. >> rose: so when they saw the images... >> it induced cravings. >> rose: it induced craving. >> a very interesting study that was, i guess, about ten or 15 years ago with the veterans from vietnam who had gotten hooked on very effective heroin. very high-quality heroin. and the amazing thing was, they got addicted in vietnam but they could give up the addiction when think came to the united states because the clues that they had that encouraged them to use the drug were gone. >> rose: no longer a part of their life. >> here the averaged a detective walks out and sees the same... this is the guy that sold it to me, this is the drugstore nearby where i met him and he's reminded of the things that

trigger this response. >> so obviously we're learning a lot about imaging. can we learn anything from animal models about this? >> yes, absolutely. most advances in modern medicine have come about through the use of animal models where aspects of a human disease are recreated in a laboratory animal like a rat or mouse. a major obstacle in sky tri has been the unique difficulty in generating animal model since so many psychiatric symptoms are inaccessible in animals. hallucinations, guilt, suicidality. >> rose: you can't find them. >> right. in this context, addiction has particular promise because it's far easier to model in an animal than other psychiatric conditions. so under the right circumstances a rat or mouse will choose to self-administer and addict itself to the same range of drugs that people self-administer and addict themselves to. >> rose: >> this is very interesting, because this is also true for

fearful conditions. anxiety states can also be modeled and this is essentially what darwin said. these emotions are conserved and so one can study these emotional disorders very effectively in animals. >> absolutely. and the self-administration behavior in animals-- like in humans-- is determined roughly half by an individual's genetic constitution and half by environment. so we know, for example, that chronic stress will increase an animal's vulnerability to self-administer of a drug of abuse just as we see in humans. going back to a point that wolfram made earlier, if a subset of animals is given unlimited access to a very potent drub like cocaine or heroin, they'll actually overdose and kill themselves. >> rose: where is conscious control in all this? >> well, i think this is a complex interplay between conscious and subconscious processes as dan mentioned.

it initially starts with a conscious decision to obtain drugs. for the rat it means pressing a lever. but what we've been talking about is then that drug stimulus activates the subcortical signals like the dopamine-containing nerve cells that are subconscious and overtime can take over. >> rose: tell me about cognition and emotion. >> well, i think they're asking because cognition has been traditionally situated in the pre-frontal cortex. but we've also come to realize that that function of the pre-frontal cortex and with repeated drug use the frontal cortex loses its ability to cognitively control your desires and emotion. each one of us on any one given day has to make decisions of whether we do something we want to do or we restrain. that i want very much but i'm not going to do it because... i don't want that chocolate but i don't because i don't want to gain weight. sometimes i can control and

sometimes i cannot. most of the time i can. in people that are addicted chronically to drugs, that control becomes very difficult. and it's almost for them like... i like to sort of use the metaphor of the brakes of the brain, the ones that are exerting cognitive control. the person that is addicted to drugs does not want to take the drug. it cost them their jobs, they may end up in prison, their spouse. and yet they cannot stop it. so it's like you want to stop but if you don't have brakes, you won't be able to do it. and that's the prefrontal cortex. >> rose: peter showed me a passage from john cheever talking about drinking. and he looked at his notes and he knew that drinking was not good for him and how many times did he say "i've got to stop." and yet he said the next day at lunchtime i find myself taking a bottle of whiskey out. >> it's a powerful habit.

>> it's the same neurocircuits we've been talking about but it becomes hijacked and mediates a formation of habits that are maladaptive. so this is now meant to represent in part some of the key structures and their connections in relation to habit formation. and so as wolfram has described earlier, dopamine neurons are providing information about reward. and in particular about when a reward or stimulus is better than expected, right? and if you think about a good habit, a habit that is adaptive, we all want to form habits when they're adaptive for us and they help us survive because we can basically perform those behaviors automatically without thinking about it and it's very helpful. it's more efficient. right? so that can be driven in part by the output from a dopamine neuron because when something happens that's better than expected you want to keep repeating that kind of behavior. and so it's dopamine input into structures like the striatum and pre-frontal cortex that mediate the normal formation of adaptive habits. at the same time, when these

become hijacked during drug-seeking behaviors, what happens is that a particular cue can illicit drug craving which then in turn will illicit drug-seeking behavior. and this is mediated probably by circuitry that involves both dopamine neurons but the convergence of dopamine input and input from the amygdala into the striatum. >> rose: is this where we talk about free will? >> one of your specialties. >> well, it has come up already in this discussion that this drug addiction kind of takes you over. so, of course, you give up a part of your free will when you become addicted. whether that's conscious decision... >> rose: you've lost your free will? >> well, a certain part of your free will. but before we get to that stage of addiction, i can't live without having that water. actually, not one, but some water every so many hours. so i, mean the reswrardz a power

effect of attracting your behavior and this is already a constraint on your free will. the simple fact that we need liquids in the environment that we need to reproduce makes us lose part of our free will. we still have the choice between different alternatives but we're going in one direction and that is towards getting the reward and avoiding negative consequences. that's very clear. and the other thing we found is dopamine not only signals the reward whenever it is better than what you have received before, it also signals the risk. so risk also influences your free will behavior. and the other thing that risk does is off problem understanding the world. if the world is risky, it could either be because you don't know it enough or because there is an inherent risk, like the weather forecast. we think the weather is basically random but we understand now that better

meteorologist makes us predict the weather better. so we have reduced the risk by knowledge, by science, by experience. so if you don't have that, if you don't have the science, we are getting superstitious. we say well, if i go three times around that tree it won't rain tomorrow and i can bring in my harvest. things like this. the more we know about the world the better we understand risk and the less we will get superstitious about how certain things will happen and so this is something where we would say education and science is there to reduce superstitions and make us behave in a more rational manner. >> the question of free will is a difficult one because we all believe individuals must be responsible for their decisions. >> rose: that's where i was going. >> and the bottom line is that drug addicts make bad decisions. the difficulty comes in with the

fact that the drugs are targeting parts of the brain that control our ability to make those decisions so we have to balance. and i think nora would agree. we have to balance between looking at an addict from the concept of free will responsibility yet they do have a drug-induced responsibility in their brain. >> these are not bad people, these are sick people. people are addicts. can we do anything about this? are there any treatment approaches that are effective? >> absolutely. one of the vital challenges of today is to translate the increasing knowledge we've gain of brain-reward circuit. the reason of the brain dan mentioned earlier. and the increasing understanding of the way drugs change the brain at a molecular level into better treatment. the best treatments today are behavioral. things like step-12 programs like alcoholics anonymous. but recidivism is high. a large majority of addicts return to using drugs even after a few months of completing the best available programs.

our view is that the goal of medication treatments would be to help counteract these powerful biological forces that drive an addiction and thereby make rehabilitation and psycho social efforts that much more effective. >> rose: wouldn't you say the behavioral treatments are really changing the brain? >> yes. both... >> rose: so the 12-step program is, in fact, changing the brain. >> yes. even though we think often times about behavioral therapies and medication therapies as different, they both work through biological processes. in other words, they would both produce positive changes in the brain. >> rose: in the end there's biological behavior at both ends. >> like you're praning the pre-frontal cortex to be able to regulate these habits, basically. >> and i wanted... the point that i want to speak of when we talk about addiction as a treatment of the brain, it's a chronic disease. so we need to consider it as a chronic model of disease. and i want to emphasize because it's very frustrating for me when we're trying to get insurances to pay for treatments

of substance abuse and they say "treatment does not work." and it does not work because 70% of patients relapse. well, they relapse because you discontinue treatment. we have the magical thinking that we're going to cure addiction. currently we do not cure addiction. we treat it like so many other chronic diseases. hypertension, asthma, cancer. and you have to maintain treatment otherwise the patient relapses. so the concept of high relapse rates is part of the concept of the long-lasting changes. brains affect... drugs affect the brain for a period that's much locker after you stop taking it. and therefore the importance of maintaining treatment. and we do have some good medications. for example, in the case of heroine we have methadone. for the case of nicotine we have several. >> rose: what do they do, all of those, as a category? whether it's nicotine or whether it's methadone? >> for methadone and for nicotine replacement you have

drugs that are acting in the same molecular targets in the brain as the drugs themselves. but they do in the a different way. temporarily a much lower level of still... >> a heroin addict, for example, would spend most of his or her day trying to get heroin and taking it. then the drug wears off and the process starts all over again. methadone binds to the same receptor that's being activated by heroin only it stays on the receptor for a very long period of time. so a person's life can garage gradually get back to normal. >> rose: but do you then have methadone addiction or not? >> you do. but it's not as disruptive and it allows normal life to begin to... >> one of the things that emerges from this discussion is how discriminated the addictive person is. for example, drug companies spent practically no effort trying to develop effective drugs against addiction. >> and that is correct. and it's actually... as a result of that it has been very

difficult. all of the signs that eric was telling us about has translated in some very potentially promising targets for medication but to bring them from the laboratory into the clinic is very costly. and for most of the diseases that we know about those casts are carried by the pharmaceutical industry. in the cases of addiction, the pharmaceutical industry has not been very much involved with the treatments for addiction. >> rose: why is that? >> one of them is the stigma that eric was speaking about and another one is the perception that the person that is addicted to drugs is not going to be able to provide for the cost, the economic cost. >> they think most people who are addicted-- which is not true-- are people on the street. but you also have people who are addicted in major executive positions. >> rose: universities, everywhere else. are we at a point in which most people believe that addiction is a disease? >> yes, yes. >> rose: and not similar play weakness of kharker?

>> i think nora is one of the people who have been making this clear to the general public. >> rose: but have you won the battle? >> that's where it comes. you're asking me and i say yes. but when i ask that to physician that are the most knowledgeable about it i ask them and they say yes, but. and that is where you have have they accepted it. they intellectually have accepted it but it has not changed their behavior which is the health care system for the most part has really removed itself from the screening and the treatment of the substance user. and the reason that it is the boss is because it is believed to be a behavior of choice. a choice of the individual when they start taking drugs. and that has been used to stigmatize the problem of drug addiction. but it's not fair. if you look at the numbers in the united states of kids that get exposed to drugs, 40% of kids 18 to 19 years of age have been exposed once in their lifetime to marijuana. 75 or more have been exposed to

alcohol. and yet some of them will become addicted and others will not. approximately 10%. and that is not something you choose, that's genetically determined. >> rose: what comes under the umbrella of addiction? drugs, everything from what to heroin, cocaine. alcohol? >> alcohol. >> rose: food? >> there is a lot of interest right now in terms of considering certain compulsive behaviors as addictions. like compulsive eating, compulsive gambling, compulsive sexual behaviors. >> rose: they are addiction in the same way? do you think there may be... >> behaviorally it's very similar. and we have been doing stories comparing the brains of people that are addicted and comparing them with people that are obese to try to understand whether the same stray yayal dopamine circuit is involved and it shouldn't be surprising but it was surprising to us at the

beginning how similar the changes are in these two conditions. and it's not surprising because drugs are hijacking a circuit in the brain that evolved to ensure that we had behaviors that would allow us to survive. what are those? reproduction, food. drugs basically take... >> one of the great hopes that emerges out of this is society is more willing to accept obesity as a disease than it is drug addiction. and getting insight into how to prevent obesity-- which is an addictive behavior in a certain level-- might spread and give us insight to the development of drugs for other kinds of addictive diseases. >> before we say that the addiction involves the same brain centers for these different forms of addiction like food and drugs and money, we can at least say here already at the completely unaddicted

state that this same part in the brain called the striatum shows responses activated by all kinds of different rewards. like money, beautiful faces as opposed to standard faces, sports cars as opposeed to standard cars. pleasant music as opposed to background music. humorous comic strips as opposed to informative comic strips and also romantic love. this is the... people see pictures of a partner with whom they have fallen in love within the last half year and that activate it is try quay tum more than compared to seeing a picture that they have gotten to know since half a year. so all these different rewards seem to activate the striatum. now you understand that addiction is an exaggerated form of brain response and behavioral response to rewards and you can imagine if this is already the same part of the brain activated with awards, addiction could

have certain similar anatomical components. >> that's the hijacking idea. >> so it's no surprise that the food reward and maybe the drug reward or something have certain similar components. >> there also are some hopeful things. for example, there's reason to believe there are stages in drug abuse. that certain drugs are more likely to lead to other drugs. smoking, for example, is a power. first step. and as one discouragings people from smoking-- and that's beginning to happen-- it quite likely will have an effect on other addictive processes as well. >> and actually eric's wife has been instrumental in her work with looking at the epidemiological studies to slow that kids that were engaging in illicit substances have started by taking nicotine. so is it because that was the first drug that are available or is it because those kids who are going to take illicit substances

are taking nicotine or is it because nicotine is doing something in your brain that could make you more vulnerable as you grow into an adult to other substances and addiction. and there is evidence from stories in laboratory animals that, indeed, early exposure to nicotine modify it is function of the dopamine cells, making them less sensitive to reward. and so, yes, nicotine exposure early on can have longer lasting effects, certainly in laboratory animals, that will affect the way that you're going to be responding to drugs. >> rose: it's on everybody's mind because of all the stuff that's gone on in the last four or five months ago tiger woods. the idea of sex addiction. what do we know about that. >> the coolidge effect. that a male exposed to female will after a while tire of cop lating with that female, but the you show him another female, that same male who appears exhausted will all of sudden be

capable of sexual activity. >> rose: why is that? what happens in the brain to make that true? >> there is some habituation going on. familiarity which is no longer forcing... it's very much like addiction. >> expected reward over time. >> but it made me also smile because it's the same thing with food. with food you can actually... they put you a piece of meat you can tire of it. then they bring dessert, even though you're full, you'll bring that dessert. anything that is novel will be salient and activate the dopamine system. >> rose: say that again. everything gets tired at some point and activates... >> becomes tolerant. so a stimulant that's pleasurable, a natural stimulant, will activate t dopamine cells. but as you become sated, as you repeat it... >> it becomes less effective. >> not with drugs, and that's one of... >> rose: why is drugs different? >> you do not become satiated. >> rose: is it possible that part of the addiction is to risk? >> that's exactly right.

and i think that's one thing that characterizes the behavior of people that take enormous risk in having, say, multiple sexual partners, right? it's not just the sexual satisfaction, the risk and enjoyment they get from doing in the dangerous situations, right (and wolfram has spoken about that. so this danger may k make accentuate the sense of pleasure they get from these types of activities. >> the interesting thing is some of these same reward neurons are also activated by risk. the other brain structure that responds to stimuli is over the frontal cortex. it's the same area. so they're very close by. >> there's another interesting feature. eric has shown an experimental animals that as you become addicted there are an tom mall changes that you say. so the chances of doing it again

are increased and this is probably the case with risk as well. we don't have the data there but probably as you engage in this and you're successful with it, you're encouraged to try again and again. >> rose: in every episode that we have done we've devoted a portion of it to genes. is it less... is there less evidence here of the genetic connection? >> addiction is half genetic which is an astounding figure based on how the role of psychosocial factors contribute to addiction as well. yet it's 50% genetic. that's as heritable as high blood pressure, high cholesterol. >> rose: and they can identify the genes. >> no. that's what nora has been mentioning. we are just now getting the techniques in molecular biology that would enable us to find these genes. >> but in animals you can do something that's very neat. which is modify one gene and that dramatically modifys the vulnerability of that animal to take the drug and to compulsively ingest it.

so with one gene you can dramatically clang the vulnerability of an animal. just illustrating how important these genes are determining the way that we're going respond drugs. and again this is not surprising when you go out with your friends and go to dinner and have a glass of wine you can rapidly see how differently we all respond to the same drug. and that... the reason why we're responding differently is because of your biology, your genetics. >> rose: (laughs) yes, it is. indeed, true. let me go to what you do at the national institute of drug abuse. what are you doing there? what's the goal and what's the support you have from the government? >> well, the institute that funds researchers in order to advance the knowledge of... in drug abuse and addictions such that we can prevent and treat the drug addiction in this problem. i always say my simple, simple task is to get people that are very, very bright to be able to get them the resources that they can use their brains and

actually come up with solutions to the problem. so we focus in two major areas. how can knowledge help us prevent. how can knowledge help us through science? and that involves, of course, very basic science like work that you're hearing today. but also it involves a better understanding about what practices are going to be more effective which we currently have for which there is knowledge. there is knowledge and yet we're not applying them. so what practices are more likely to prevent and treat people such that we can decrease the significant burden of drug abuse in this country. >> rose: all right. let me conclude with this, which everyone knows i like to do. in research, in the study that you do, what is the one question you would like to see answered. >> how can we cure addiction? >> free will.

>> rose: free will? >> identifying specific genes that control vulnerability or resistance to addiction. learning how the pre-frontal cortex can regulate our emotions. >> i'm interested in learning and memory and addiction is, in fact, a learning process. we've recently begun to explore a moll yule that is involved in per pec situation of memory storage and it would be interesting to know whether it's involved in the per pec situation of addictive process. why people relapse so easily. they can be off drugs for months but they walk out on the street, they see a sign, boom, it's like a condition stimulus they go back and get addicted again. i would like to see what this kind of a molecule is involved in that as well. >> rose: what do you think we'll be talking about ten years from now if we convene the same group to talk about the emotion in the brain. >> emotion is an area that we knew very little about in biological terms 20 years ago. we've made remarkable progress. so i think this is an area in

which the progress would be disproportionately large. i think we'll have a much better understanding of the reinforcing systems of addiction. we may have initial insights into how to combat addiction and we'll see how obesity and drug addiction relate to each other. so many of the themes that we outlined here will make progress. having said that, i should tell you in biological terms ten years is a very short period of time. >> and i think we would also have a bert knowledge about conscious and unconscious emotions because so much of our behavior is controlled by unconscious processes, including unconscious emotions. >> this is what freud said. (laughter) >> nobody... right. >> rose: so there is our panel waying in on part one of our two-part look at emotion and the brain. part two is? >> negative emotion. we're going to discuss fear and disorders related to fear. we're going to focus in

particular on post-traumatic stress disorder and there is good news about this disorder. there are now a number of rather effective treatments, both behavioral treatments and psychofarm logical treatments that are extremely effective in helping people with post-traumatic stress disorder. >> rose: so there is a biological basis for post-traumatic stress disorder? >> that's right. that's right. >> rose: thank you for joining us for this. we look forward to seeing you next time. emotion part two: fear and sang sighty. see you then. captioning sponsored by rose communications captioned by media access group at wgbh access.wgbh.org