they're brilliant learners. >> rose: the fifth episode of the charlie rose brain series, underwritten by the simons foundation coming up. captioning sponsored by rose communications from our studios in new york city, this is charlie rose. >> rose: tonight we continue our exploration of what many consider the most fascinating topic in science. the human brain. in previous episodes, we examined how the brain controls vision, movement, and social interaction. tonight,we will look at how the brain actually acquires its amazing abilities. our subject is the developing brain. every newborn is introduced to a world that is entirely foreign and unknown. however, the adaptive ability of the infant brain is nothing short of miraculous. within days of birth, a newborn starts building the foundation for a lifetime of knowledge. he or she learn to respond to colors, to recognize objects, and to discern the properties of the physical world. tonight we'll look at how this learning takes place. what cognitive tools do infants use to understand the world around them? how do they acquire language? are these skills learned spontaneously,or do they require outside instruction? and perhaps most importantly, what kinds of abilities are innate and what kinds of abilities must children get on their own? findings show that newborns possess much greater cognitive capacity than previously thought. skills such as object recognition, facial recognition, and even basic number recognition can be inborn. one thing is certain: babies are much more than empty vessels waiting to be filled with knowledge. they are primed from birth to gather information on their own. this evening, we'll also learn about the anatomical changes that occur in the brain as a person grows from a fetus to an adult. just like every other part of the human body, the brain begins as a single sheet of cells. unfortunately, aspects of the growth process occasionally go awry. tonight, we'll also focus on a handful of diseases known as the developmental disorders, rett syndrome, fragile x syndrome, and fox p.t. syndrome all arise from defects in single genes each interrupts a different stage of brain development with devastating consequences. joining me tonight, a remarkable group of sciences. they are elizabeth spelke, her work as shown that infants are born with much greater cognitive abilities than ever before imagined. she is a cognitive psychologist at harvard university, where she is director of the laboratory for developmental studies. patricia kuhl-- she's one of the world's leading authorities on speech development. she is a professor at the university of washington where she is director of the center for brain and learning sciences. she's also the author of "the scientist in the crib." huda zoghbi-- she studies the genetic origin of developmental disorders such as rett syndrome. she is the director of the january and dan duncan research institute, and a howard hughes medical investigator. stephen warren-- his work focuses on the understanding of the causes of mental retardation. he's a professor of emory university in atlanta. and once again my co-host is dr. eric kandel. as you know, he is a nobel laureate, a professor at columbia university, and also a howard hughes medical investigator. he has been our companion, he has been our guide, he has been our guy on understanding the brain. good to see you again. >> pleasure to be here. >> so we begin with the question what do we mean by the developing brain? >> we are exploring together one of the great miracles, as you indicated, in the natural world: the emergence of the human mind. this is an extraordinary adventure. an infant comes into the world with an enormous curiosity to learn and acquires these systematically. not only to recognize faces and abstract things. they learn how to acquire language, they learn how to acquire numerical systems. they don't do this instantaneously. they don't do it simultaneously. they do in the stages. >> rose: this name, who is famous for understanding the developmental stages. >> jean piaget. he's a giant in understanding the steps whereby kids learn about the natural world. and he came across in this in an interesting way. he found it isn't just kids getting more intelligent with time, becoming more like adults in acquiring information, but found that their qualitative thinking changes. they are capable of handling certain kinds of information only at certain stages in development. so that at early stages, they cannot understand certain processes that are certain to understand. he did most of his work in switzerland, but spent some time in france. and there he translated the i.q. test into french and he gave this test to lots of young kids very bright kids. and he saw at certain ages invariably they got certain answers wrong that seemed very obvious to him. and a few years later, they would be able to do very well. let me give you an example. so you have two small beakers with an equal amount of fluid. if you take one of these beakers and pour it into the larger one, you will see that you now empty this one beaker and you fill the other. let me try this as an experiment with you, charlie, to see whether or not you can manage to do this. two blue beakers-- if we now pour this into that... and i ask a very simple question. which beaker has more fluid? this or that? >> rose: (laughs) they're the same. >> brilliant! you pass! kids don't realize that the volume stays the same irrespective of the shape of the vessel. >> rose: because? >> because they think if it's tall, they think it must be bigger. and at some time two or three years later, when they're seven years old, they all of a sudden boom get this perfectly well. >> rose: you know what amazes me eric. here's one more, john paiget, born in 1889, somewhere right before the turn of the century. here we are talking about one aspect of since that is right at the cutting edge where there's such unknown but we're learning so fast. yet it's one more example, as i've seen in our exploration of the brain, where there were these giants without the without the modern technology able to make amazing ground-breaking analysis. i like to compare it to freud. he focused only one period of life. freud focused only on... all aspects of the life cycle. he focused only on infancy. but he differed from freud in another way. he carried out experiments. this is an experiment that he did. so he introduced experimental science into developmental psychology. which was extremely important, and he came up with some wonderful notions about this. he pointed out that not only these stages, but these stages have characteristic features. one is they're social. that is, in order to acquire certain aspects of knowledge, and patricia kuhn made fantastic contributions of this-- you need social interactions. so if you want to learn a language, you learn it from another human being. you cannot learn it from a television set. moreover, these stages in cognitive development are paralleled by stages in brain development. and we can see that, as kids mature, the brain grows, it adds nerve cells, it forms new connections, and these connections strengthen in certain areas, they weaken in certain areas. you can see the brain mature with time. and this parallels intellectual development. >> rose: from birth until maturity, it doubles in size. >> that's right. absolutely. and as is the case with all areas of medicine, there are tragic events that occur. in a rare number of cases, genetic mutations interfere with these developments and they can lead to rett syndrome, the fragile x syndrome. we'll have a chance to discuss this. so we see the whole range from psychology to biological basis of behavior in this discussion today. also one of the fascinating things that we will see is the importance of interactions between genes and environment. >> rose: for all that we will say, parents will ask "what can i do to make my child... to maximize their intelligence? their ability to learn? can i have an impact?" >> parents are born to have an impact, just as children are born to take advantage of that impact. social interaction is absolutely critical for the intellectual development of the child, number one. number two, as children go through these various developmental stages, their brain is particularly susceptible to acquiring new kinds of information. so exposing children widely to numbers games, to language if you want a child to learn a second language, it's critical that they begin this very early on. that you should be perfectly comfortable having the child be bilingual. in fact, they'll acquire a second language much, much more readily early in life than later on. and enjoying the children and seeing... having the child see how pleasurable the child's activity is for the parents. so i think interaction is key for assuring healthy outcome of it. >> rose: all right. our developing brain, that is our subject this evening. we have assembled for you a remarkable group of people, as i said, and we begin our conversation understanding the development of the brain. erybody, i think, understands this one big idea that somehow it's easier for children to understand languages than adults. >> yes. that's the case. infants go about language using both innate skills and an incredibly powerful learning mechanisms that we're just beginning to understand. and whether they're born in singapore or paris or seattle or new york, they'll all follow a set of universal stages, as eric alluded to. at three months they'll koo, at seven months they're babble, at a year, a single word, at 18 months two-word combinations and at the age of three full sentences, they will talk your leg off. and so what is it about that magic that they can put to work? and it exhibit what is the biologists have always called a critical period in development. so if you look at your age and assess your skill in acquiring a second language, you see a very dramatic learning curve that's the reverse of what we typically expect. adults with superior cognitive skills typically get better, surpass children at learning things. but in the area of language, from birth to seven years of age, the kids are masters. whether they hear a single language or two or three, they will acquire them effortlessly. but beginning at the age of seven, that begins to decline. age ten, 11 to 15, 17 to 39, past puberty-- which is everyone at this table-- we really don't have the same machinery. the brain is not working in the same way. and we don't learn second languages as well. >> it's actually a very interesting point because it doesn't simply apply to language. >> right. >> musical skills, athletic ability. unless you start early, you can never reach the levels... >> rose: that's the worst news i've heard. (laughter) >> it's terrible! >> rose: i'm leaving. >> but we're beginning to understand that many aspect of development have these critical periods and, in fact, this one, the critical period for language has embedded in it many critical periods for learning of the sounds of the language, the wording of the language, the grammar of the language. >> rose: what is it about the brain that enables it to learn language? >> well, that's the question, charlie. so no one debates this curve. but everyone is debating what's the cause of that function. why does it work in that way? why does the baby brain work in a way that the adult brain doesn't? so the classic debates-- they've gone on for centuries. so currently, noam chomsky from m.i.t. and the late b.f. skinner from harvard debated very different tasks, very different takes on this debate. chomsky arguing the structure is built in the brain, and skinner saying "we're born a blank slate." so what's new, what's happened? well, what's happened is that the scientists got into the picture and started to actually study the brains and minds of children look at their skills. and that's produced an entirely new view that isn't either of those canonical opposites. and i can illustrate it by taking one aspect of language. the development of the sound processing of language. i'll show you how that works. so when we think about the sounds of language, each language uses a different set. so in japanese, "r" and "l" are not distinct. to a japanese speaker and listener, "rice" and "lice" are the same thing. but in english, the kids have to learn that "r" and "l" are distinct. how do they come about doing this? we have gone all over the world testing babies, and i want to show you a film clip that illustrates the test. we're looking at what sound contrast the babies at six months can hear in all these countries of the world. we've been in nine countries testing with the sounds of ten languages. and the answer is the same. the videotape will show babies sitting on a mother's lap. there's a person sitting with a box of toys and distracting the baby. the baby's got to learn that when the sound being produced in the background-- ah, ah, ah-- changes to anything else, the baby has a three-second opportunity to turn towards the sound source and see a black box with a dancing bear or something fetching in it. >> can a baby as young as six months old hear the difference between two vowels? this baby is trained to look for the toy when the sound changes. she's being distracted so she'll turn only when she hears the difference in sounds. the key question, will she turn before the toy lights up? (sound changes) >> so that baby knows what she's doing. she knows she's done it right. so the key of the... the key answer to our tests demonstrates that the baby babies at birth and until six months what are we like to call citizens of the world. they can discriminate the sounds of all the languages that we put in front of them. there isn't a single one they fail at that. contrasts with you and i who hears the sound contrast used in their particular language but not the others. we simply can't hear those distinctions anymore. there are two critical pieces that babies are putting to work between eight and ten months. you say, "what is the magic they're putting to work that you and i can't put to work?" there are two very different answers. one is they're doing something we like to call computation. because they're picking up statistical properties of the language that we produce for them. they're, in essence, taking into account the frequency, relative frequency, of the sounds they hear. and they're also taking account of the transitional probabilities between syllables. it's an amazing computational skill. we call it statistical learning. but what we've also demonstrated is that this statistical learning capacity, which comes online at about that time, seems to be under the control of the social brain. now, i know you've talked about the social brain on this program. so you know all about the machinery that is interested in bodily movement and eye tracking. >> rose: right. >> well, we've done experiments where we bring babies into the laboratory for the first time at nine months, right in the critical period for sound perception learning, and we expose them a language they've never heard before. in this case we're going to see a clip of exposure to mandarin. 12 sessions between nine months and ten months the babies play on the floor with my native mandarin-speaking graduate students and post-docs, and we want to know what is it doing to their brains to get this new language. can they take the statistics on a brand new language? then we contrast that learning with learning done on a television set. same schedule of... same dosage, same material. what happens in the learning? the dramatic finding is that only babies in the social condition learn, and they learn so well if they're exposed to mandarin their sound perception becomes as good as the babies in taiwan who have been listening for ten months. >> rose: wow. >> so the right information the brain at the right time in development and learning is incredible. >> i, e, e, r. >> rose: amazing. >> the babies stare at the television set, and for all the world you think something's going on in their brains, but when you take the measures after these 12 sessions, i don't know, live other or television, the kids in the television condition have learned nothing. >> rose: beyond language. what other skills? >> well, one of the things that i think is so fascinating about these years from birth to age five or so is that while the child is engaged in this huge task that pat's describing of learning their language, they can't just focus on that, because they also have to be learning everything else about the world. they have to go from an infant to can't even reach out and get their hand on to an object to grab it effectively, to a five-year-old who actually saw in one of your earlier programs can outperform any robot in motor skills. they have to be able to come to recognize all the objects around them and figure out what they're for and what kind of actions you do with them and where you put them away, we hope they'll learn. and they also have to be able to learn basic things about how the world works as the piaget experiment that eric demonstrated showed us. and i think that raises the question, what makes kids so amazing at this task? now, the two features that pat already focused on in the case of language, i think also apply to learning in these other domains. it's also true when children are learning about objects, when they're learning new motor skills that they're terrifically good at focusing on other people and getting information from what other people are doing, and they're also really good at getting statistical structure, as you were saying, out of the world. but i think there are two other pieces of this puzzle, at least, that we need to add into the mix in order to account for these incredible feats that we see kids engaging in. the first of them is that children come into the world prepared to construe it in the same basic fundamental kinds of ways that we do, and that's going to be crucial because if i'm going to learn things from you, from what you do, i better be able to understand your actions and and the things that you act on in the same general kinds of ways. let me give you just one example of this. like eric, i brought a demonstration in. >> rose: a learning tool. >> a very simple event. i'm going to take this cracker, put it into a cup, take out again, put it in again. you've now seen it go in and out three times. and over here, i'm going to take a cracker, put it into the cup, take out my empty hand, and now take a cracker and put it in to the cup. now, you saw more motion over here than you saw over here, but you'll immediately be able to say there is one object here eye have to remind myself. ( laughter ) i could immediately say-- over here and two over here. and what that ability shows is that we can take the surface appearances of things, the momentitary entrance of an object, and we understand them as manifestations of a set of bodies that exist, whether we're looking at them or not, that behave in accord with basic laws so we can predict what's going to happen next. we know put something in a cup it will stay there, unless you take it out. and this general ability, piaget called it object permanence when he rightly pointed out this is fundamental. to our understanding of the world. well we now know that very young infants, really as young as we can test them, within the first couple months of life, have the same ability. my favorite study was actually on somewhat older infants. i think they are about ten months old. just old enough to appreciate the virtues of crackers like this. so investigators at johns hopkins university presented children with these events and asked them what's going to be a bigger draw? it will be the cup that had more cracker motion, more stuff they saw, or the cup with more crackers? and the babies very clearly went for the crackers, not for the cracker motion. but more sensitive methods with much younger infants, infants who don't yet know about crackers and about cups show that already within the first months of life babies are construing the world in terms of enduring objects. objects that they take to exist whether they can see them or not and that ability allows infants to follow things over time, to make good predictions about what they're going to do next so they can begin the task of acquiring the specific knowledge about the cups and the crackers, what's edible what's not, what we do with different kinds of objects. so i think a piece of the puzzle of why we're such good learners is that we start from a terrific starting point. >> rose: what's going on inside the womb? what's going on in that brain before birth? >> the brain starting developing quite early during pregnancy. as early as three weeks of the pregnancy, things will start happening. by four weeks, almost the first structure that will make the brain is formed, and that structure will undergo a lot of cell divisions, many neurons will be born. they'll take their places so by 17 weeks of pregnancy the the shape of the brain as we brain's already starting to take the shape of the brain as we know it. and with time now, from 17 weeks on, that brain will keep on adding more and more cells and imagine this brain being confined within a very small space, the skull. so to pack up more neurons, the brain starts contortions and gyrations will start forming so that by the time the baby's born it has packed about 100 billion nerve cells. >> can you show us a visual of that? >> if we look at the pictures, you'll see what the brain looks like at 17 weeks of age, notice how smooth it is. all the cells have made it in and with time we're gradually adding more and tacking more so that by 40 weeks of pregnancy when the baby is born it has quite a few cells. now this process is impacted by both external factors and internal factors. the internal actors are the genes, many molecules that are telling cells where to go, how to find the right place and there are external factors, what the mother will eat during the pregnancy, what drug she is might use, why viruses she might be exposed to. >> rose: right. >> all of these factors come to play so that we have the brain as you see it. so this is what you see at the outside. if you look at that gyration, that's the cerebral cortex, where our perception of the world around us happens. now let's look on the inside what happens inside the brain. and this is really beautiful, because it's almost like choreography. we start off very early in the pregnancy, a few cells are born and they have to migrate and find a place within that cortex. so the first layer of cells will be migrating. the next group of cells will divide and migrate; they'll go past the old ones and take a new position. and this process will continue until you have six layers. all these layers have very specialized neurons for the brain to function properly. think of a thousand dancers at the opening of the olympic ceremony. imagine them having to make the color of the olympic flag and to have to perform a coordinated dance. if any of them takes the wrong spot, the dance will be ruined. and that's exactly the situation with the brain. we talked about intrinsic factors, genes. if we were to study animal models, we've learned quite a bit about which genes tell neurons to go to which spot within these layers. and if we look at an image from the cortex of a mouse model, you're going to notice nice layers of brain cells or neurons, they're different colors. you see the pink ones, the green ones, and the blue ones. you take away one gene and you can imagine how this animal might be like. the animal will have seizures, many other complications because the brain cells have not taken their exact position. so everything has to be done precisely. now what happens after these brain cells take a position? they have to communicate. and brain communications continues after... the development of the pathway for self communicates with each other will happen after birth. so if we go back and look at the picture of the newborn baby, we're going to see the size of the newborn brain and next to it we'll see the adult brain. you see how much growth has happened. >> rose: about twice the size. >> almost, yes. and part of the reason we have such difference in size is because, after birth, brain development continues. it continues in many forms. first, many of these brain cells have to make different branches. they have to extend processes to communicate with each other. and if we would look at the next picture, we're going to see these type of processes. the cell on the left is sending a long process-- that's the axon down which the information will be transmitted to the next neuron. the point of contact is the synapse. the synapse is where two neurons will communicate with each other, and that is the key factor for why we're able to learn, why we can retain part of the conversation tonight. we have to have healthy synapses. in a newborn, the synapses will start developing but between two years and two months of age, that's when baby will have the largest number of synapses. the babies in the brain will have a lot more synapses than they will end up with as an adult. if you look, you'll find that the brain is actually sculpturing itself during this period. it will make so much more synapses, and with time and experience-- based on the baby's experience or the child's experience-- some of these synapses will be eliminated and some of them would be strengthened. and it's really tantalizing that this critical period, when we see the largest number of synapses formed in the children it sort of overlaps with this critical period when language acquisition is at its best. >> in fact, one way one can think about this-- one doesn't really know yet-- to explain the phenomenon that pat was talking about, how one loses the distinction between certain words in a language that one doesn't use is one loses certain connections and strengthens others. so the kind of things that huda's talking about probably participate in this phenomenon. >> yes. that's the dream, to put these two pieces of information together-- the physiology, to understand how that brain is sculpting itself, and when it does that very exciting sculpting; and how that maps on the learning curves for various skills that we're very interested in, like language. >> we can see not only in the language domain, but in other domains as well, two things. one is that a supportive social environment makes a big difference for children. but the other is that children have extraordinary intrinsic capacities to learn at about the age of two. children have two different kinds of numerical abilities that they've had since infancy. the first one i already told you about-- they can represent exact numbers... small numbers exactly. the difference between one cookie and two, or even two cookies and three. children at age two also can represent large numbers approximately. so you show them an array of eight dots and an array of 16 dots, they can readily tell you that there are more dots in the array of 16, even when you adjust the sizes and spacing and things so that they have to focus on number. but there are two interesting limits to young children's numerical abilities. the first is, we think of the numbers one and two and eight and 16 as all the same kind of thing. but there's good evidence that in infants and young children these are actually captured by separate systems that work in different ways, both in behavioral tasks and also in some tasks using functional brain imaging. they engender different patterns of activity. but second, this capacity to deal with any numbers larger than three is radically imprecise. so a two-year-old child can tell you that eight is less than 16 and even that eight is less than 12, but can't even begin to tell you that eight is less than nine or to think the thought "there's an exact number of things on this card." and what i'd love to do is show you a clip of a child who visited my lab two weeks ago who's two and a half years old, and is just grappling with this problem of figuring out "what are the people around me talking about now?" >> rose: why are they doing this? >> can you count them again for he? >> one, two, three, four five... >> can you put one fish in the pond? >> yup. i put one. >> is there one fish in the pond? >> yes. >> thank you! natalie, can you put two fish in the pond? >> yup. are there two fish in the pond? >> yup. >> yes. thank you. >> i'd like to point out she's doing three things that are brilliant. the first, which is another example of learning from other people, is she's figured out a lot of what goes into this counting routine. she's got the first three words at least in order, she's pointing to objects at the right time and so forth. second of all, she's figured out that when she's asked for one, she should put her small exact number system to work and produce exactly one object. she's also learned that when she's asked for another one of those words that you use when you're counting, she should put her large approximate number system to work and produce a bunch of things. what she hasn't figured out yet is how does she integrate what she knows about large numbers and what she knows about small numbers in a systematic rule- bound way to yield the natural number concepts that she'll need in school, and that we are using... that seem to come so naturally to us. and the fascinating story is this is a hard task for children, but they figure it out on their own. >> rose: one of the great things we're talking about is how to... what's natural and what instinctively happened versus what is learned. >> this is a beautiful example of how the two interact. in other words, the social environment but also the genes and how important they can be for the development of the brain. >> well, so as huda beautifully described, the developing brain is the product of the genes. so you're born with this incredible machine and now can absorb the environment and absorb experiences and mold itself. just as pat said, it doesn't matter what continent you're born on, you have the ability to learn language and it doesn't matter particularly what that language is. we know genes play an important role because we see families that have a tragic consequence of having a particular disorder move throughout the family in a simple fashion. so we can look at family structures, pedigrees, where we represent males as squares, females as circles. >> rose: right. >> and show that, for example, a phenotype, which is some recognizable characteristic or disorder, moves from parent to child and so on down through the pedigree. and this gives us a very powerful ability, then, to identify the genes responsible. these are rare disorders, but they give us a window into what's going on. >> rose: what triggers these genes? >> well, there's a cascade of events that happen. some genes control other genes, there's a timing event during development, how cells interact when those... as huda was describing when the neurons move about in the developing brain, they kind of form a local environment that then communicates to their neighbors and turns on genes, turns off genes. so the repertoire of the genome is a complex orchestra of how it is turning genes on and off in... on cues that are sometimes environmental, sometimes driven by other genes. >> rose: what do we know about the impact of what some people call toxic elements in terms of brain development? >> environmental factor? >> rose: yes. alcoholism, that kind of thing. >> correct. so some of these things we talked about extrinsic can factor that can affect brain development. for example, alcohol can affect brain development, can cause trouble even with the baby's development, defect in the headline. some environmental toxins can affect things much earlier, actually, than just in the womb. they can affect the sperm or the egg, creating genetic defects that then will give rise an abnormal child. so there are really a variety of factors. viruses can cause developmental brain abnormalities. drugs can affect it. so there are a variety of things. and partly, the reason, because these element cans affect gene expression. that's how they actually work. we don't think about it, but a toxin can affect when a gene is turned on or off, either in the sperm or in utero, and that's part of the problem of these toxic elements. >> one of the really important things we need to understand is to bridge the biology that huda and steve is talking about to the cognitive psychology that the two of you are talking about. what kinds of headway can we begin to make in that? is there any beginning in that? >> i think there is a beginning. i think we're looking at developmental disorders in a way that says we know there's a genetic tendency-- for example, in autism. we know some of the pieces that have to come together to bring about changes in these twin deficits that children with autism show in language and social cognition. so the interesting interplay in the next decade i think will be to understand the genetic predispositions that we're all walking around with, and then to what degree can we push them around, push around the outcomes, by rearranging situations, interventions early in development when the brain is so plastic, when it's being... it's carving its synaptic growth and pruning and alter the course of development in a way change the outcome. >> rose: this is the question that eric and i have had many conversations about. how much dialogue is going on between people representing the different aspects of the psychological as well as the molecular? >> well, i mean, both of these people are doing experiments in which using imaging or... >> rose: imaging, exactly. >> e.e.g. equipment. and perhaps you could discuss that. >> so there are a couple of things to look forward to. one is that early measures... say at six months, we can now measure the baby's brain's ability using event-related potential to hear to distinctions, the brain's reaction to the distinctions between sounds. that measure at six months of age predicts language at three... and quality of language at three and reading readiness at five. now, that's quite extraordinary. so that says if someone... if a baby is really not hitting the milestones... >> these are like biological markers. >> these are markers, these are biomarkers. so this is one thing that's happening in all of the laboratories now where people are using the brain measures to take a precise measure of a precursor that we know is going to be very important, that this milestone be passed before you get to a more complex one. and then on the horizon are brand new metrics that allow whole brain imaging. and i've got a video of that. m.e.g., it's whole brain imaging that non-invasive can be used for newborns to aging adults and it's picking up the magnetic field changes as the brain does its work. so we've now been testing babies at six months and 12 months while they're engaged in a cognitive task, and because it's so safe and we've got g.p.s. tracking on their little heads so we know exactly where the brain structures are, we can test them in tasks that involve math or learning mandarin from a real person as opposed to a television set, and seeing how these areas of the brain communicate with one another. how does that long distance communication happen between the language areas and the social areas so that social understanding can gate the learning mechanisms for language or other tasks. >> in all areas of medicine, we learn an amazing amount from tragic cases in which the brain development is disturbed as a result of genetic disorders. we've learned a great deal from rett syndrome, fragile x. >> what about rett syndrome? how does that work? >> rett syndrome is fascinating. it's named after an austrian pediatrician, andreas rett, he saw these patients in his clinic and now we've seen many of these patients around the world. and what happens is they're born normal, they can learn how the do everything a one-year-old will typically do, some of them will actually learn how to speak a few words, so willl even learn how to say nursery rhymes. they'll be able to use their hands, feed themselves, play with toys, socially interact. and then something happens, and it happens during that critical period that we've talked about. somehow, this part of the regular post-natal developmental program gets interrupted and these girls all of a sudden stop using their hands, instead just constantly wring their hands. they'll use the social skills, they'll lose coordination, they'll lose any language, they'll lose balance and they'll have motor difficulty and with time will develop spasticity, they'll have seizures, anxiety and a variety of other medical and neurological problem. it really affects all parts of their brain. so it's quite an unusual disorder, but what it taught us that this critical post-natal developmental period is really important. if we look at the video, we'll show a video clip of a girl who started life as normal. you see her picking a toy and she's picking the toy with her hands, she can run around, she's functioning just as a perfect one-year-old would normally function. here she is at a couple years of age going through the book, she's using her hands well, she can use the book. and she's still doing quite well. now you'll notice she's not quite steady on her feet. she can't anymore use her hands and instead what she'll do is hold her hands together and constantly wring them. doesn't have as much social interaction, she'll have seizures and a variety of neurological problems. this happens time and time again to all these girls and the question what happens? and the way we were able to start to learn a little of what goes on in the child's brain when they have rett syndrome is first by finding the gene, and then when you find the gene you can genetically engineer animal models to study what happens. you can replicate the mutation that's in the human, engineer it in the mouse and see whether the mouse reproduce the features of rett syndrome. having a mouse model you can look at what's happening in the brain before the symptoms develop, during, and through the course. and what was really surprising-- would you think a mouse will wring its hands if you gave rett syndrome mutation? and that's the case. so we'll look at a video clip of a normal mouse, and you'll see how a normal mouse will keep its paws apart. and then... this is a healthy normal mouse keeping its paws apart, and if you hold the rett syndrome mouse model... >> amazing. >> look at that. >> you'll see how it will be wringing its paws together. >> wow. >> rose: and this mouse will have all the features that we see. it has learning problems, it has balance problems, it will have seizures, all the problems we see in the human. and it turns out that the protein that's lost in rett syndrome is really critical for those synapses we talked about. so if we look at a healthy brain after all the sculpting and the pruning happens, you have to have just the right number of synapses between two communicated neurons, and this is what we would expect in a healthy brain. in the case of the rett syndrome what happens when the protein is lost, we have fewer synapses. so having fewer synapses is not sufficient for normal brain function. we're learning about the thousands of proteins of the synapse where the neurons communicate with each other. we know that losing one copy of a gene for any one of those proteins or having an extra copy of that same gene can give us cognitive disabilities, autism spectrum disorders, a variety of neuropsychiatric syndromes. so the brain is really finely tuned, as you've heard, and having too little or too much is really... >> you see this also in fragile x. >> absolutely. the synapse when they're forming there's tiny machines in there that use proteins, the proteins are made-- and this is wonderful experiments that professor kandel conducted-- proteins locally right by the synapse in order for them to function. they will strengthen or weak than synapse. well, a protein in fragile x syndrome helps balance that. so you have signals coming into the surface of the synapse that stimulate this is protein to be produced. the fragile x protein sort of balances that out. so, again, it's a situation br where you need to have a finally tuned amount of proteins. too much is not good, too little is not good. and in fragile x syndrome, when you lose this one protein that's sort of the brake on this system, you now over-express too many of these proteins. and that causes, then, these synapses just to be too weak. >> i think this is a beautiful example of how brain scientists come together. we're going hear from discussion of cognitive disorders in kids, normal kids, we're seeing how these various stages evolve, we've seen how they can go awry with genetic defects or environmental defects. we can begin to study them in animal models, and one of the many functions of animal models is we can begin to define them as targets for developing drugs. and these are terrible disorders. if we could begin to reverse them, it would have a major impact on public health policy. >> i'll show a clip of some mice that have been treated with one of these. you see four mice, and they're all engineered like huda talked about, so they have fragile x syndrome. but one of the odd things that the mice do with fragile x syndrome is they have what's called audiogenic seizures, so if you play an obnoxious tone to them, they jump around all over the cage and can't handle it. a normal mouse doesn't quite respond that way. so we're going to show a clip of four mice and they're identical mice-- all of them have the fragile x mutation. but the two mice on the left are untreated. the two mice on the right are treated with one of these compounds, and then you turn a tone on and this is what you'll see. >> rose: that's amazing. >> it's really amazing. >> that's a long way from this to the human but this is the way you begin. >> rose: for all the... either parents or potential parents watching this, what do you want them to take away from this? >> they should remind themselves that they're the child's first and best teachers, and what they tend to do naturally-- which is to interact socially, to speak in motherese and to play games and allow them to explore the kitchen, the pots and pans and spoons and plates are playthings that will beat the d.v.d.s and special programs any day. >> well, maybe i'll elaborate on this and discuss, of course, prenatally we know that many environmental factors affect the health of the brain so be as healthy as you can be with nutrition, physically avoid drugs, alcohol, et cetera. but i think one things that's really important to remember and this is more to the parents of children with developmental disabilities, we're now learning that many of these disabilities can... symptoms of them can be reversed. so the brain is really much more plastic than we thought. so i think we should hold some hope that with research and some of these animal model studies that maybe we can do something. especially for those diseases that don't occur until one or two or three years-- autism being one, perhaps rett syndrome and other disorders. so that's another thing. >> take the time to enjoy your child. do it not only for your child, because i fully agree with everything that pat said. you are the best environment for your child to be growing up in. but do it for yourself. this is an absolutely fascinating time in life, and a time when things are changing so fast that, from one day to the next, from one week to the next, you're dealing with a different creatures, with new abilities. take the time to enjoy them. >> rose: let me then ask finally. what is... what do you most want to know within your field? what's the biggest question you would like to see answered? >> to answer that honestly, i'm going to have to turn away from questions about parents and children, and say that the question i'd most like to have the answer to is how is it possible for a human brain to think an abstract thought? you've learned on this program, you've talked about how the brain only gets input from its perceptual systems and it only affects the world through its action systems. but there are limits to what we can see and there are limits to what we can do. but we can close our eyes and we can imagine a line that's infinitely long, a point that's infinitely small, a series of numbers that goes on forever, and our ability to imagine those things forms the basis of everything from formal mathematics to science to technology to everything that we are. i don't think we understand how the brain does that. i think for all the advances that have been made in genetics and neurobiology, we don't know where abstract ideas come from. but my hope is if we could figure out how little kids get to have them, we might start making some progress. >> rose: great. >> actually, it's very similar to you. i think that, you know, if we could figure out how genes influence, say, schizophrenia. how do you generate a hallucination because you have a mutation in some genes? i mean, that's a profound progress from a simple gene and a protein in a synapse to a circuit that's somehow recreating experience that was... that occurred earlier. so i think someday to explain these psychiatric disorders that are very complex but they have genetic underpinnings, so must have variation in the genome is fascinating. >> i'm very interesting in understanding gene environment interactions better and co- opting that to help patients. so we know that, for many of the disorders, it's really about gene/environment interaction. we're born with our genes-- we can't do much about them. but we can do something about our environment. so finding ways to actually modify the function of genes through understanding these external environmental factors, and we know this could help many brain disorders would be fascinating. just like the toxic chemicals; there has got to be good chemicals or good environmental factors. i'd like to know them. >> i think from discussions such as this, one can see that, in a reasonable period of time, we go to get an insight into what we can do with our children in order to bring out the best in them. but in addition, we can go one step further. we've really not used science to improve the educational process. it would be nice if we could have an impact in pedagogy on how to really optimize the experience of pre-school children and children in school in order to have them assimilate knowledge better. they have this enormous capability that they're born with, and often school takes it out of them. and we need to create an environment in which kids can use this. >> rose: absolutely. >> the brain and mind are the new frontiers. we're just on the cusp of understanding how abilities like language-- which have been debated for centuries: what are the origins of language-- how does that come together in an individual child? i'm looking forward to gleaning from all of the scientists that are now coming together to talk in detail about how it works on the ground. and imagining that in our lifetimes, we will be able to do what all parents feel like they want to do when they look in the eyes of their child and that's to understand what's going on up there. we'll discuss age-related memory loss, we'll discuss alzehimer's disease and we'll see what we know about these disorders and how can one possibly try to prevent them in the future. >> rose: i look forward to it. episode six, charlie rose brain series with dr. eric kandel. see you then. captioning sponsored by rose communications captioned by media access group at wgbh access.wgbh.org tavis: