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GRAY MATTERS: The Developing Brain - Final Script
(Public Radio International/Audio Logo) Announcer: THE FOLLOWING PROGRAM, "GRAY MATTERS: THE DEVELOPING BRAIN," WAS PRODUCED IN ASSOCIATION WITH THE DANA ALLIANCE FOR BRAIN INITIATIVES. (Sounds of new baby's first cries...Music in) WHEN A CHILD IS BORN... WE COUNT FINGERS AND TOES TO MAKE SURE THAT THE BABY IS NORMAL. WE LOOK FOR A STRONG, WRIGGLING BODY... AND LISTEN FOR A HEALTHY CRY. YET, THINK HOW MUCH MORE WE WOULD LEARN IF WE COULD LOOK INSIDE THE BABY'S BRAIN. WE WOULD FIND A ONE-POUND, WALNUT-SHAPED COLLECTION OF NERVE CELLS THAT, IN ALL ITS VARIATION, WOULD GIVE SOME CLUES ABOUT THE KIND OF PERSON THIS GURGLING, LAUGHING INFANT WILL SOME DAY BECOME. (Sounds of a laughing baby...) HELLO. I'M JUDY WOODRUFF. THE DEVELOPING BRAIN OF A CHILD ORCHESTRATES A FEVERISH LEVEL OF EXPLORATION AND DISCOVERY. IN A PROCESS THAT BEGINS BEFORE BIRTH, CHILDREN DEVELOP THE WIRING OF NERVES AND CONNECTIONS THAT WILL ALLOW THEM TO MAKE SENSE OF THE WORLD. DURING THE NEXT HOUR, WE'LL EXAMINE HOW THAT NEEDY INFANT BLOSSOMS INTO A READING, WRITING, AND ROLLERBLADING 10-YEAR OLD. (Ambience of older kids at play/Music resolves) Shatz: I always think it's an incredible miracle that most of us walk around and we're actually, we do ok everyday. DR. CARLA SHATZ IS PROFESSOR OF NEUROBIOLOGY AT THE UNIVERSITY OF CALIFORNIA, BERKELEY -- AND PRESIDENT OF THE SOCIETY FOR NEUROSCIENCE. Shatz continues: If you think about the number of connections that have to be made, and in fact, just think about it for a minute - there are something like, well, there are probably over 100 billion neurons in the brain. And if each one of these neurons make about 100 connections with other neurons, which is a reasonable thing to think, then there are almost literally billions and billions of connections that have to be formed in order for us to function normally. To me, it's just a miracle that most of us walk around on this planet and go about our daily business and do just fine... (New music in) THE MIRACLE BEGINS WITH A SINGLE CELL, CREATED WHEN SPERM AND EGG COMBINE. THE GENES ARE JUST A BLUEPRINT, AND EVEN AT BIRTH, A BABY'S BRAIN IS ONLY PARTIALLY WIRED. MILLIONS OF DETAILS ARE FILLED IN THROUGH THE CHILD'S EXPERIENCE. Shatz: One of the things that I think is so incredible about brain development and that I think one generally doesn't realize is that initially all the various parts of the brain aren't even connected. It's like you know, a whole series of cities growing up on their own, and then after a while, the roadways get put down and all the connections form between them. And it's really like that. BUT EVEN THE NEWBORN BABY HAS SOME IMPORTANT SURVIVAL TOOLS. HE CAN BREATHE. HE CAN EAT. HE CAN CERTAINLY CRY. DR. SUSAN CURTISS OF UCLA... Curtiss: At birth children are essentially helpless. And we need to take care of them. And one of the ways they can get us to take care of them and in fact struggle through and keep taking care of them despite the fact that they're giving us practically no sleep, and exhausting us emotionally and physically, is because they are very cute. That's just part of the biological plan.
(Music in) BUT TO THINK OF A BABY AS POORLY PREPARED IS PERHAPS TO MISS THE POINT. CHILDREN ARE BORN INTO A BEWILDERING VARIETY OF ENVIRONMENTS, FROM THE TERROR OF A WAR ZONE TO THE COMFORT OF A PARK AVENUE PENTHOUSE. WILL A CHILD HEAR MACHINE GUN FIRE OR MOZART? WILL HE NEED TO SPEAK ENGLISH OR URDU. WILL SHE BE EXPOSED TO A LARGE EXTENDED FAMILY OR A SINGLE MOTHER? THEIR BRAINS MUST BE READY TO ADJUST TO WHATEVER ENVIRONMENT THEY CONFRONT. FOR YEARS, DR. PATRICIA KUHL, A SPEECH SCIENTIST AT THE UNIVERSITY OF WASHINGTON, HAS BEEN LISTENING TO INFANTS MORE CAREFULLY THAN EVEN THE MOST DEVOTED MOTHER. (Clip/Kuhl infant vocalizations) Kuhl: When we test infants at birth regarding the sounds of language, and you test them with African sounds and American English sounds, and Japanese sounds and sounds borrowed from all languages. You see that no matter where the baby is being reared, the baby distinguishes these very fine differences in, you know, temporal cues and spectral cues and duration cues. They're really sensitized to the sounds of language and they're universally so. So we like to say that babies are born citizens of the world. KUHL HAS FOUND THAT THESE "CITIZENS OF THE WORLD" ARE READY TO LEARN ANY LANGUAGE THEY HEAR. BUT AS EARLY AS SIX MONTHS OLD, THEY START TO SPECIALIZE. AS A TEST, KUHL MOVED HER ENTIRE LABORATORY TO STOCKHOLM TO SEE WHAT SOUNDS BABIES AT SIX MONTHS COULD DISTINGUISH. Kuhl: So what we saw in the babies in Sweden and in the babies in America was this ability to ignore the minor variations, and attend to the central categories of sound, uniquely for their native language. So the Swedish babies would perceive the category of the vowel "oooo," which is a rounded front vowel that doesn't occur in American English. And the Swedish babies would perceive that as a category of sound. And the American babies were doing the same thing for the vowel "e," as the word Pete. And so we think that this is a first step. It sounds like a small one, but from the standpoint of a baby, the formation of these categories around their native language sound is exactly what they need to do to move to the next stage of development which is to the stage at which you perceive words. (Sound of a 1-year-old, vocalizing with American mom) THIS FORMER CITIZEN OF THE WORLD IS WELL ON HER WAY TO BECOMING AN AMERICAN. (Music bridge) THE CHILD'S BRAIN IS DEEPLY AFFECTED BY EXPERIENCE. A MOTHER'S TOUCH, HER SOOTHING VOICE, A BARKING DOG, A SQUEAKING TOY...ALL OF THIS SENSORY STIMULATION SHAPES THE CHILD'S BRAIN. WHEN A CHILD IS EXPOSED TO A RICH ENVIRONMENT, THE BRAIN ALMOST GLOWS FROM THE MILLIONS OF ELECTRICAL CONNECTIONS THAT ARE FORMED IN RESPONSE. NEUROLOGISTS SAY THAT A CHILD'S BRAIN IS PLASTIC. THE PLASTICITY SHOWS UP EVERYWHERE -- SHAPING A CHILD'S PRIMAL ABILITY TO SEE AND HEAR -- TO THINK, AND SPEAK, AND REMEMBER. AGAIN, DR. CARLA SHATZ. Shatz: The child's brain is not just a miniature version of the adult brain. It's a very dynamic, changing structure that is slowly evolving into an adult brain. Perhaps one of the best known examples of brain plasticity in human development is in the visual system. And a wonderful set of experiments that were done many years ago now by David Hubel and Tortsen Wiesel, who received the Nobel Prize in Physiology and Medicine in 1981 for their work was to show that in the visual system there is a critical period during which normal visual experience is essential for normal brain wiring. And in fact, they were very interested in the question of why children who have a congenital cataract are unable to recover the vision in their eye. If your grandmother has a cataract in adulthood, you can correct the cataract, and she's perfectly able to see again. So what's different between the child's brain and the grandmother's brain? And what they discovered by using animal models..to make essentially a model of cataract, was that in the child's brain the connections are still forming between the eye and the brain. And if the eye has a cataract, and the cataract isn't removed right away, the connections aren't used from that eye, and they actually wither away. And actually, the connections from the other eye, if anything, get stronger than normal. On the other hand, in the grandmother's brain, when a cataract has formed in adulthood, those connections are essentially hard wired and they don't change. THE PLASTICITY OF THE YOUNG BRAIN IS SHOWN MOST DRAMATICALLY IN A NEW TREATMENT FOR EPILEPTIC CHILDREN. A NEW BRAIN IMAGING TECHNIQUE CALLED THE PET SCANNER (FOR POSITRON EMISSION TOMOGRAPHY) HAS SHOWN THAT IN EXTREME CASES, THE BRAIN DYSFUNCTION THAT CAUSES SEIZURES EXTENDS THROUGHOUT AN ENTIRE HEMISPHERE OF THE BRAIN. FOR THESE CHILDREN (WHO CAN HAVE UP TO HUNDREDS OF SEIZURES A DAY), EPILEPSY IS A DEVASTATING, DEGENERATIVE DISEASE. PEDIATRIC SURGEONS LIKE DR. HARRY CHUGANI AT CHILDREN'S HOSPITAL OF MICHIGAN HAVE DEVELOPED A RADICAL TREATMENT: REMOVING UP TO HALF OF THE CHILD'S BRAIN, A PROCEDURE CALLED A HEMISPHERECTOMY. AND AMAZINGLY, THE YOUNG BRAIN IS SO PLASTIC THAT MOST OF THESE CHILDREN RECOVER, SEIZURE-FREE AND ARE ABLE TO PERFORM MOST ACTIVITIES NORMALLY. DR. MICHAEL PHELPS IS CHAIRMAN OF THE DEPARTMENT OF MOLECULAR AND MEDICAL PHARMACOLOGY OF THE UCLA SCHOOL OF MEDICINE. Phelps: When we would perform the surgery, and remove the seizures and the abnormalities from the brain, they would now reverse that trend. They would go from degeneration to regeneration. They would be born again, as one mother put it. And they would now start back in their life of developing with their language, their cognitive skills, their motor skills....and be able to perform in a single hemisphere what the two hemispheres had been doing before.
(Music) (First or second grader begins reading a story...) WHEN IT COMES TO LANGUAGE, MOST CHILDREN ARE LEARNING MACHINES. FOR 25 YEARS, DR. SUSAN CURTISS, PROFESSOR OF LINGUISTICS AT UCLA, HAS BEEN STUDYING THE WAY CHILDREN LEARN LANGUAGE. Curtiss: One thing that children do is they overregulate plurals and they will say things like "foots" and "mouses." We think that this is very cute and it is very cute, but it also is very revealing because it tells us that they know a very complicated rule. WE THINK OF THE ENGLISH LANGUAGE PLURAL AS A SIMPLE THING -- JUST ADD AN "S." BUT, IF YOU'RE THREE YEARS OLD, AND YOU DON'T KNOW WHAT AN "S" IS, IT'S REALLY QUITE COMPLICATED. YOU CAN ADD AN "S" TO DOG, OR CAT, OR HOUSE, BUT LISTEN TO HOW DIFFERENT THE "S" SOUNDS AT THE ENDS OF THESE WORDS: "DOGS," "CATS,"' HOUSES" YOUNG CHILDREN SOMEHOW MANAGE TO LEARN IT ALL. Curtiss: The fact that they say "foots" and "mouses" tells us they have a plural rule. Mouse, if it were a regular word like house, we say houses, so mouse should be mouses. And by the same token if we say boot, boots, why don't we say foot, foots. So it is cute that they say foots and that they say mouses. But it's very telling that they do so. Because they're telling us that they actually know a very complicated rule of grammar that they weren't taught. Parents don't even know they know this rule themselves, so the parents can't possibly be teaching it to them. But they are giving them the rule just by speaking to them. And children's brains are finely tuned to do this incredibly complicated thing that we call language development. THIS REMARKABLE ABILITY TO LEARN PLURALS IS A SMALL EXAMPLE OF THE CAPABILITY OF THE YOUNG BRAIN. Curtiss: The developing mind is extremely powerful, and a child can learn any language, the grammar of any language, and comes equipped, comes equipped to do so. And does so within a remarkably short amount of time given how complicated every individual human grammar is. I mean linguists have worked arduously at determining the properties of English for example, probably more than any other language. And yet we still don't have a full description of the grammar of English. So not even one human language yet has a full description and yet children seemingly effortlessly learn within their young childhood, before they get to school predominantly. And the grammar almost fully, so this is a really remarkable feat. IN FACT, WE KNOW NOW THAT WHEN IT COMES TO LEARNING LANGUAGE, AN IMMATURE BRAIN OFFERS A HUGE ADVANTAGE. Curtiss: Even in late childhood, like at the age of nine or ten, one cannot learn a first language fully or naturally or normally. So we can see that there's actually a developmental window, a very special time, sometimes referred to as the sensitive period or a critical period. And what seems to be happening is that during the course of childhood the brain is becoming slowly less plastic, and by the time the child reaches puberty, the brain has become significantly less plastic and is not able to restructure itself. And consequently, the mind as well as the brain in essence becomes rigid and cannot develop richly and normally any real cognitive system, including language. (Music) THE YOUNG BRAIN OBEYS A RUTHLESS COMMAND: "USE IT OR LOSE IT." DEVELOP A SKILL DURING THE CRITICAL PERIOD WHEN THE BRAIN IS READY, AND YOU MAY REMEMBER IT FOR LIFE. FAIL TO LEARN THAT SKILL WHILE THE WINDOW IS OPEN, AND YOU WILL NEVER HAVE ANOTHER CHANCE TO LEARN IT AS WELL. AT THE AGE OF TWO, A CHILD HAS TWICE AS MANY CONNECTIONS, OR SYNAPSES, IN HIS BRAIN AS THE AVERAGE ADULT. WHEN CHILDREN ARE BORN, THEY HAVE MILLIONS OF CONNECTIONS JUST WAITING FOR A SPECIFIC ASSIGNMENT. AS THE WORLD MAKES DEMANDS, MANY OF THE CONNECTIONS ARE DEPLOYED FOR A SPECIFIC JOB -- SEEING, HEARING, REMEMBERING, THROWING A BALL. THE CONNECTIONS THAT AREN'T USED AND MAINTAINED ARE WEEDED OUT -- "PRUNED" AS THE BRAIN SCIENTISTS SAY.
AGAIN, DR. MICHAEL PHELPS. DR. BRUCE MCEWEN OF ROCKEFELLER UNIVERSITY EXPLAINS THE UNDERLYING ACTIVITY. McEwen: Connections between nerve cells are formed often in greater abundance then selectively eliminated or caused to re-form as the pattern of stimulation and experience goes on. And generally there's an evolution of greater complexity even though the brain is at birth largely formed in terms of its basic components. A FOUR OR FIVE-YEAR OLD LEARNING A SECOND LANGUAGE IS A PERFECT MODEL FOR THE IDEA OF THE CRITICAL PERIOD. AGAIN, LINGUIST DR. SUSAN CURTISS. Curtiss: Children are completely capable. I mean the power to learn language is so great in the young child that it doesn't seem to matter how many languages you seem to throw their way. They can learn sign language and spoken language at the same time. They can learn as many spoken languages as you can allow them to hear systematically and regularly at the same time. Children just have this capacity. Their brain is just ripe to do this and they are able to do this and there doesn't seem to be any detriment to knowing you know and having the opportunity to develop several languages at the same time. That just seems to be a gift that can only expand them. BUT IF A CHILD WAITS UNTIL HIGH SCHOOL TO START STUDYING A FOREIGN LANGUAGE, HE'LL FIND THE JOB MUCH HARDER. Curtiss: Now we're talking about learning. Now we're talking about reading books and listening to the teachers and trying to learn a skill like what the rules of this other language are. Translating from our language to this other language and trying to figure out as many good strategies as we can, problem solving strategies for learning language. MANY OF THESE LATE STARTERS LEARN BARELY ENOUGH TO ASK FOR DIRECTIONS OR ORDER A MEAL IN ANOTHER LANGUAGE. (Music) BRAIN SCIENCE TELLS US WHY THAT HAPPENS. IT'S NOT THAT THE TEACHER IS MISGUIDED OR THE LANGUAGE TOO HARD OR EVEN THAT WE SHOULD STUDY MORE. THE BASIC PROBLEM IS THAT WE START TOO LATE. THAT TENTH GRADER STUMBLING OVER "BUENOS DIAS" AND "COMO ESTAS" HAS ALREADY MISSED THE CRITICAL PERIOD FOR LEARNING ANOTHER LANGUAGE. HIS BRAIN HAS PRUNED AWAY THE NEURONS THAT WOULD HAVE LET HIM MASTER SPANISH EASILY. SO IF YOU'RE LOOKING FOR A MORE PROMISING LANGUAGE STUDENT, FORGET HIS HIGH SCHOOL CLASSMATES; TRY HIS FOUR-YEAR OLD SISTER INSTEAD. Sounds of young girl laughing -- playing/ambience continues under. TO UNDERSTAND BETTER HOW CHILDREN LEARN LANGUAGE, RESEARCHERS LIKE DR. ALLISON DOUPE, AT THE UNIVERSITY OF CALIFORNIA, SAN FRANCISCO LISTEN CLOSELY TO BIRDS... (Birdsong ambience)
Doupe: Bird brains are not the same thing as human brains and this is always
true for all animal research, but they are composed of very similar cells and
they, these bird brains, have specialized areas that are just for song
learning and production, just like we have specialized areas for vocal
learning and production that we don't share with other primates. AS WITH CHILDREN, BIRDS MUST HEAR THEIR SONGS AT A CRUCIAL TIME OF DEVELOPMENT. IF THEY DON'T THEY PRODUCE SONGS LIKE THESE... (isolate song sample) THIS IS THE SONG OF A BIRD RAISED IN COMPLETE ABSENCE OF AUDITORY EXPERIENCE...CALLED AN "ISOLATE." IT SOUNDS LIKE A SIMPLIFIED VERSION OF THE SONG OF NORMAL BIRDS OF THE SAME SPECIES... (Isolate sample continues) Doupe: It's not that they don't sing at all. There's something genetic that's predisposing them to make a certain type of sound, but without the experience during their early life, they can't make the full repertoire. AGAIN, DR. CARLA SHATZ. Shatz: This turns out to be a wonderful model in some ways of human language development. Because like human languages and language acquisition, there's a critical period for bird song. The birds have to hear their own species specific song during a very limited time, during after birth. And then they have to practice it just the way our own babies practice language by the first simple sounds that they make. And then those sounds got more elaborate, and then they're able to produce that song in a kind of crystallized form. ALTHOUGH A RELATIVELY SMALL FIELD, BIRDSONG RESEARCH IS NOW UNDERWAY IN 25 LABS IN THE UNITED STATES. IT'S PART OF AN ERA OF EXPLOSIVE GROWTH IN BRAIN SCIENCE. Shatz: It's illustrated by the growth in our field and our professional society that started out with a few hundred members 25 years ago and now has almost 25,000 members in the society. And so there's been obviously the explosion in knowledge has come through an explosion in excitement about brain research. And also an excitement about the promise for cures that will come soon as some have already come from... this kind of research. (Music) COMING UP IN THE NEXT HALF HOUR: BREAKTHROUGHS FOR LEARNING DISABLED CHILDREN -- AND IMAGING TECHNIQUES THROUGH WHICH WE CAN WATCH THE LIVING FUNCTIONS OF THE BLOSSOMING BRAIN. THIS PROGRAM IS PRODUCED IN ASSOCIATION WITH THE DANA ALLIANCE FOR BRAIN INITIATIVES, AN INDEPENDENT, NON-PROFIT ORGANIZATION MADE UP OF OVER 140 OF THE NATION'S LEADING BRAIN SCIENTISTS, INCLUDING FIVE NOBEL LAUREATES, AND IS DEDICATED TO ADVANCING BRAIN RESEARCH AND EDUCATING THE PUBLIC ABOUT ITS PROMISE. I'M JUDY WOODRUFF -- AND YOU'RE LISTENING TO "GRAY MATTERS" FROM PUBLIC RADIO INTERNATIONAL. (Ambience - extended segment of kids at play/HALF-HOUR BREAK) HAVING A HEALTHY CHILD IS CERTAINLY NOTHING WE CAN TAKE FOR GRANTED. I HAVE THREE CHILDREN. MY ELDEST, JEFF, WAS BORN 14 YEARS AGO WITH SPINA BIFIDA. I HAD NEVER EVEN HEARD OF SPINA BIFIDA BEFORE THE ARRIVAL OF MY FIRSTBORN. HE CAME INTO THIS WORLD WITH WHAT'S CALLED A NEURAL TUBE DEFECT. DOCTORS DESCRIBED THE CONDITION AS THE FAILURE OF THE SPINAL CORD CASING TO CLOSE. IT OCCURS WITHIN THE FIRST 30 DAYS OF PREGNANCY. DR. GODFREY OAKLEY IS DIRECTOR OF THE DIVISION OF BIRTH DEFECTS AT THE CENTERS FOR DISEASE CONTROL IN ATLANTA. Oakley: When one is in that 3-4 week period there is something called a neural tube that must develop properly for all of the brain and nervous system to work well. When spina bifida occurs, it occurs from a failure of the proper closure of the neural tube at the lower end. Children with spina bifida are usually born alive and most live today. But children with spina bifida usually have varying degrees of paralysis - and one statistic that sticks in my mind is that the average child with spina bifida will spend six months of the first years of his/her life in a hospital having one surgical procedure after another. TODAY, APPROXIMATELY ONE OUT OF 1,000 BABIES IS BORN WITH SPINA BIFIDA. WHAT WE HAVE LEARNED IN THE LAST FIVE YEARS -- AND IT'S EXTRAORDINARILY GOOD NEWS -- IS THAT ABOUT THREE QUARTERS OF THESE BIRTH DEFECTS CAN BE PREVENTED IF THE MOTHER CONSUMES ENOUGH VITAMIN B, FOLIC ACID. Oakley: The US Public Health Service issued in September of 1992, the recommendation that all women who could get pregnant should consume every day 0.4 milligrams of folic acid in order to prevent spina bifida and other neural tube defects. I'm often asked how much is that. It's 100% of the US RDA. It is the amount of folic acid in the usual multivitamin -- and it is the amount of folic acid that would be in any serving of a breakfast cereal that has 100% of the US RDA per serving in it. DR. OAKLEY CALLS THE FOLIC ACID DISCOVERY THE MOST IMPORTANT FINDING IN THE PREVENTION OF BIRTH DEFECTS SINCE THE RUBELLA VACCINE. ANOTHER DRAMATIC BREAKTHROUGH IN BRAIN SCIENCE RECENTLY IS THE DEVELOPMENT OF IMAGING TECHNOLOGY THAT ALLOWS US TO ACTUALLY WATCH THE BRAIN'S CHEMISTRY AND BIOLOGY. PREVIOUSLY, WE STUDIED THE BRAIN BY LOOKING AT HUMAN AUTOPSY TISSUE AND BY DRAWING ANALOGIES FROM ANIMAL BRAINS. NOW, FOR THE FIRST TIME, WE CAN WATCH THE HUMAN BRAIN IN ACTION. CO-INVENTOR OF THE PET SCAN, DR. MICHAEL PHELPS. Phelps: If you look at an autopsy of the brain where the person is dead, the brain is not functioning, you see the different structures of the brain, the frontal cortex where the cognitive processes take place; the visual cortex that allows us to see; auditory cortex that receives and interprets the information from our hearing. But remember the person is dead. But you can see those structures. In the PET scan, you see those structures also. But in fact you watch them perform the living functions of the brain. TO TAKE A PICTURE OF A CHILD'S BRAIN, YOU MUST FIRST FIT HIM WITH A CAP, EQUIPPED WITH SENSORS THAT MEASURE ELECTRICAL ACTIVITY WITHIN THE BRAIN. THEN YOU ASK THE CHILD TO PERFORM SPECIFIC TASKS -- THINK OF A WORD THAT RHYMES WITH "CAT" OR DESCRIBE YOUR WEEKEND AT THE BEACH. THE SENSORS THEN RECORD THE BRAIN ACTIVITY -- AND DEMONSTRATE THE RESULTS ON MULTICOLORED MAPS THAT HIGHLIGHT WHICH PART OF THE BRAIN IS MOST ACTIVELY ENGAGED.
(Musical cues/punctuation throughout) Phelps: You can see the visual cortex. And the auditory cortex and the frontal cortex. But in addition, you now watch the functions occur in those structures. If a person opens their eyes, you see suddenly the chemical activity increase in the visual cortex. It comes alive. If the person begins to think about what they're seeing, you see areas of the frontal cortex light up now. So the functions of the brain can be watched and observed while you watch the person perform them. THESE NEW IMAGING TECHNOLOGIES MAY OFFER HOPE TO THE 15 MILLION CHILDREN AND ADULTS WHO SUFFER FROM DEVELOPMENTAL BRAIN DISORDERS SUCH AS MENTAL RETARDATION, CEREBRAL PALSY, OR LEARNING DISABILITIES... DR. REID LYON OVERSEES THE RESEARCH PROGRAM ON LEARNING DISABILITIES AT THE NATIONAL INSTITUTE OF CHILD HEALTH AND HUMAN DEVELOPMENT. Lyon: When you ask someone to read single words silently and you image their brain, or the activation of the brain as the person does that, you don't just see one place in the brain that's activating. You see a constellation of zones in the brain that seem to 'come on' at the same time and appear to work in a concerted fashion to produce a simple behavior like reading the word "cat." And what that might tell you is that difficulties in reading the word "cat" aren't referable or cannot be linked to just one brain difficulty. But in fact may be linked to any one or several of these zones that appear to operate just doing that one simple task.
(Ambience of classroom - in and under) BY THEN, THE LEARNING PROBLEMS ARE HARD TO TREAT, AND THE CHILDREN HAVE OFTEN DEVELOPED EMOTIONAL PROBLEMS AS WELL. DYSLEXIA IS THE WORD WE USE TO DESCRIBE READING DIFFICULTIES THAT ARE NOT TIED TO A PERSON'S INTELLIGENCE. SOME PEOPLE THINK OF DYSLEXIA AS THE SIMPLE REVERSAL OF WORDS. THE CLASSIC EXAMPLE IS A READER WHO SEES THE LETTERS "T-O-P" AND SAYS "POT." BUT DYSLEXIA IS ACTUALLY A MUCH BROADER DISORDER, INVOLVING CHRONIC DIFFICULTIES IN READING AND WRITING. DYSLEXICS HAVE TROUBLE MASTERING THE FUNDAMENTAL SOUND STRUCTURE OF THEIR OWN LANGUAGE. THEY STRUGGLE WITH THE BASIC CODE OF LANGUAGE: "B" HAS A "BUH" SOUND, D HAS A "DUH" SOUND, AND SO ON. AS A RESULT, DYSLEXIC CHILDREN, EVEN VERY BRIGHT CHILDREN, DON'T READ OR WRITE FLUENTLY, AND TYPICALLY FALL FAR BEHIND IN SCHOOL. THE NATIONAL INSTITUTES OF HEALTH NOW ESTIMATE THAT AS MANY AS 20% OF ALL CHILDREN ENCOUNTER SIGNIFICANT PROBLEMS LEARNING TO READ. WHY DO SO MANY CHILDREN HAVE SO MUCH TROUBLE WITH SUCH A BASIC HUMAN SKILL? PERHAPS THE REASON IS THAT READING IS NOT SO BASIC A SKILL AFTER ALL. SPOKEN LANGUAGE IS A UNIVERSAL HUMAN QUALITY, BUT WRITING HAS BEEN WITH US FOR JUST A FEW THOUSAND YEARS -- A BLINK OF AN EYE IN EVOLUTIONARY TERMS. Shaywitz: Reading is a relatively new phenomenon. Language has been around for tens of thousands of years, but reading is rather new in terms of evolution. And it would be difficult to imagine that suddenly a new system has evolved in the brain just to serve reading. DR. SALLY SHAYWITZ, CO-DIRECTOR OF THE YALE CENTER FOR THE STUDY OF LEARNING AND ATTENTION, HAS BEEN STUDYING DYSLEXIA FOR MORE THAN TWENTY YEARS... Shaywitz: Reading is more difficult than language. When children learn to speak we have to remember that the basis of language is really the phoneme. The phoneme is the basic sound, the smallest discernible unit of sound. All words in the English language are made up of phonemes. And what do I mean by a phoneme? For example, the word bat is made up of three phonemes: (buh-ah-tuh). And with these three phonemes an individual can synthesize every word in the English language and that makes, actually English or any of the alphabetic languages very democratic because you only need to learn approximately 44 phonemes that together make up the English language. And with those 44 phonemes you can make up any word. The brilliant and wonderful thing about language is that this is all done automatically and unconsciously. The difficulty with reading is that even though reading is based on phonologic principles as spoken language, reading is not automatic, it must be taught. In order to learn how to read, an individual must begin to learn that the letters, the orthography, the graphics that are present on a page represent the same sound units that an individual hears in spoken language. WE NOW KNOW THAT THE BASIC DIFFICULTY WITH DYSLEXIA IS IN DECODING SINGLE WORDS. THIS REPRESENTS TREMENDOUS PROGRESS IN UNDERSTANDING THE BASIS OF THE DISORDER. WE KNOW WHICH SYSTEM OF THE BRAIN IS INVOLVED -- THE LANGUAGE SYSTEM. BUT EVEN MORE THAN THAT, WE KNOW WHICH COMPONENT OF THE LANGUAGE SYSTEM IS AFFECTED. THIS FINDING MAY HAVE A SIMPLE YET INVALUABLE APPLICATION. DYSLEXIC CHILDREN HAVE BEEN SHOWN TO BENEFIT GREATLY FROM INTENSIVE TRAINING IN PHONETICS, IF STARTED AT AN EARLY AGE. Dr. Denckla (explaining the tests): D: I'm going to say a word and take away the last sound, tell me what is left behind. Hide w/out D P: Hi D: Make P: May D: Road P: row D: Seed P: See D: I didn't hear P: Seen. I mean see. D: Okay... DR. MARTHA DENCKLA IS TESTING PETER, A VERY BRIGHT SEVENTH GRADER WITH DYSLEXIA. DR. DENCKLA IS PROFESSOR OF NEUROLOGY, PEDIATRICS AND PSYCHOLOGY AT THE JOHNS HOPKINS UNIVERSITY SCHOOL OF MEDICINE. BUT EVERY WEDNESDAY, SHE USES HER HOME OFFICE IN BETHESDA, MARYLAND TO WORK ONE-ON-ONE WITH KIDS LIKE PETER. D: Now repeat this after me. Jack likes hamburgers with relish, mustard, and ketchup P: Okay, Jack likes hamburgers with relish, wait. Ketchup, relish, and mustard. Denckla: I just wanted to make it clear that Peter is a very bright boy and he has probably the most common set of learning disability characteristics that we see week after week and most of the children can be described as very bright. Peter has a good enough IQ to go to any Ivy League College in the United States. SKILLS THAT INVOLVE SPEECH SOUNDS AND SEQUENCES ARE VERY HARD FOR PETER. YET, HE CAN HANDLE ALMOST ANY INTELLECTUAL CHALLENGE. DR. DENCKLA SAYS THAT PETER WOULD MAKE A GREAT BOSS BUT A VERY POOR SECRETARY. HOWEVER, TO SUCCEED IN SCHOOL, HE NEEDS TO MASTER SUBJECTS THAT DEMAND PRECISE ANSWERS. Denckla: Reading and spelling and arithmetic are highly constrained activities in which there are correct and incorrect answers. So, I think we have to work on these things because they are realistic tools. We should, however, tighten our belts and not get too extravagant about insisting, for example, on very good spelling. Because for the 21st century, we have computers that are wonderful prosthetic devices that spell for us if we can make some sort of decent approximation. But, we are going to need to read. I don't think that reading is going to be unnecessary even in the coming century. (More ambi/Peter and Denckla...more testing) Denckla: The context I like to put this in is that these children who just don't happen to be talented in the prerequisites for reading are no more abnormal than the people who are not able to keep a tune, when somebody plays a tune, just the way you'd say to Peter, repeat this sentence precisely and he doesn't have a great facility for that. Imagine if we changed the rules and next year we decided that everybody had to sing a certain number of tunes in order to go from first to second grade and we had on grade level and below grade level singing. We would just have to have another bunch of people coming for evaluations and getting special help. NO MATTER HOW WELL PETER EVENTUALLY LEARNS TO READ, MOST LIKELY, HE WILL NEVER BE A FAST READER. IT'S AS THOUGH THE CIRCUITS HE'S BEEN LEARNING WITH ARE DETOURS, BACK ROADS -- AND NOT THE EXPRESS HIGHWAYS THAT PEOPLE WHO READ EASILY ARE ABLE TO USE. Denckla: And that means way down the road, even if Peter learns to read so that on an untimed basis he can read virtually any word put in front of him, I would still expect that when he goes to college, it will take him longer to read what he's assigned and there may need to be accommodations for that fact and the timed element in all the testing we are put through in our school system. So relaxation of time limits on tests is one thing that I think is an important concept we need to get across. (Open with brief excerpt of "Simon Says" game, Tallal...with slowed speech) DR. PAULA TALLAL IS CO-DIRECTOR OF THE CENTER FOR MOLECULAR AND BEHAVIORAL NEUROSCIENCES AT RUTGERS UNIVERSITY IN NEWARK. HER CURRENT RESEARCH IS PART OF THE DANA CONSORTIUM ON LANGUAGE-BASED LEARNING DISABILITIES. DR. TALLAL IS LOOKING FOR AN EVEN MORE FUNDAMENTAL CAUSE OF LANGUAGE DISORDERS. SHE THINKS THAT CHILDREN WITH LANGUAGE PROBLEMS MIGHT HAVE DIFFICULTY WITH SOMETHING SHE CALLS "TEMPORAL PROCESSING." ("Simon Says" as Tallal explains) AS THE KIDS MOVE AROUND IN RESPONSE TO SIMON'S COMMANDS, TALLAL IS TRYING TO EXERCISE THEIR BRAINS AS WELL. Tallal: If I want to make my biceps stronger, I can exercise by moving my arm up and down. And if I do that ten times a day, and then don't do it again for another week, and do it ten more times, it's probably not going to do very much for me. But if I do it hundreds of times per day, over a period of time in a schedule, in the end, the biceps that I exercise is going to get big and strong, actually grow. That gave us the idea that maybe what we could do with these language impaired children is to try to exercise, literally create something equivalent to brain aerobics, for the part of the brain that processes information quickly. And we would do that by giving them the opportunity to hear sounds, first of all in the range they could hear them, then slowly, slowly, slowly making them go faster and faster -- and reinforce the brain for really focusing on that piece of information. FOR CHILDREN WHO HAVE TROUBLE UNDERSTANDING RAPID SPEECH, DR. TALLAL IS TRYING A NEW APPROACH: SLOW IT DOWN TO A SPEED THEY CAN UNDERSTAND. HER COLLEAGUE, DR. MICHAEL MERZENICH AT THE UNIVERSITY OF CALIFORNIA, SAN FRANCISCO, HAS CREATED COMPUTER-ALTERED SPEECH THAT STRETCHES OUT THE KIND OF SOUNDS THAT SOME CHILDREN CAN'T EASILY FOLLOW. (Sample of sound) COMPUTERS DRAW OUT THE "STOP CONSONANTS" SUCH AS "PA" AND "BA' -- THE SOUNDS THAT, TALLAL BELIEVES, CHILDREN WITH LANGUAGE DISABILITIES TEND TO HAVE THE HARDEST TIME DISTINGUISHING. TALLAL SLOWS DOWN THE TAPE TO A SPEED THAT THE CHILD CAN UNDERSTAND. THEN, WITH THOUSANDS OF REPETITIONS, SHE TRIES TO INCREASE THE CHILD'S PROCESSING SPEED. AS THE CHILD IMPROVES, THE SPEECH IS GRADUALLY SPED UP. THE HOPE IS -- IT WILL WORK LIKE AN ASSEMBLY LINE CALIBRATED TO RUN AT THE FASTEST SPEED THE WORKERS CAN MANAGE. (Kids in action - sharing stories for points/computer prizes) THESE CHILDREN WERE ENROLLED IN AN EXPERIMENTAL SUMMER CAMP. ONLY 20 KIDS WERE INVITED TO ATTEND. BUT THIS CAMP WASN'T IN THE WOODS OF MAINE OR THE ROLLING HILLS OF VIRGINIA. INSTEAD, IT WAS ON THE CAMPUS OF RUTGERS UNIVERSITY IN DOWNTOWN NEWARK, NEW JERSEY. AND DR. TALLAL, A BRAIN SCIENTIST, WAS THE DE FACTO CAMP DIRECTOR. Tallal: Before a child ever gets to the point of having a learning disability or a reading disability, there are many of these same children who had telltale signs in some cases very marked telltale signs that they were going to go on to have language or learning problems. And these children were children who were having a great deal of difficulty learning how to talk in the early years before they ever went to school. There's a lot of individual differences in how fast a child learns to talk and when they should start and how many words they should say at what age, etc. But there comes a point, usually around the age of two and a half or three, that if a child is not saying short phrases and having a real burst in vocabulary and learning new words, etc. There's a hint there's a problem. And if a child goes on to the age of four or even five, and still has a lot of trouble either understanding what people say or expressing themselves, those children really need a lot of attention right away. Keelan clip... SIX-YEAR OLD KEELAN WAS A CAMPER AT RUTGERS. THIS FRECKLE-FACED, BLONDE, AS HER MOTHER REPORTS, HAD PLENTY OF FRIENDS BUT HAD LOTS OF PROBLEMS IN KINDERGARTEN. SHE TESTED POORLY -- AND WOULD EASILY GET LOST IN CLASSROOM ACTIVITIES AND THEN WANDER OFF TO A CORNER ALONE. AT HOME, TOO, SHE WAS FAR BEHIND HER SISTERS AND BROTHERS. Keelan's mom: She's my fourth child. It was a lot more difficult to communicate with her. Long explanations on things left her in outer space. And in school, when I went to the kindergarten teacher, they described her to me as being very immature. And it felt that was a totally wrong evaluation of her because she's socially very mature, because of being the fourth child. And they said she was silly and immature. And I said, I don't think she's getting half of what you're telling her here. ONE SPEECH AND LANGUAGE INSTRUCTOR NOTICED A PROBLEM AND SUGGESTED THAT KEELAN BE TESTED. IT WAS THEN RECOMMENDED THAT SHE BE ADMITTED TO CAMP AT RUTGERS. DURING THE FOUR-WEEK EXPERIMENTAL CAMP, CHILDREN WENT HOME EACH EVENING TO THEIR PARENTS. IN THEIR NIGHTLY HOMEWORK, THE KIDS LISTENED TO MORE OF THE "PROCESSED SPEECH" SUPPLIED BY DR. TALLAL. Tallal: The interesting thing is that many of the parents have brought some of the tapes back and said this sounds strange or there's something wrong with the tape recorder. But everyone of them has said the kids say "no, that's fine." And the only way I can explain that is when I put on your glasses everything may look fuzzy but it may look just perfect to you. So we have to keep remembering that we're not trying to make speech that sounds good to us. We're trying to make speech that may sound better to the children that are not dealing with our speech very well. (More ambience...of camp) UNLIKE MOST CAMPERS, NONE OF THESE CHILDREN WILL BE RETURING TO RUTGERS NEXT SUMMER. BUT DR. TALLAL'S RESEARCH WILL CONTINUE WITH THE HOPE THAT THESE FINDINGS MIGHT SOMEDAY HAVE AN APPLICATION IN THE CLASSROOM. Tallal: It's still very much research. I think it's really important to make it clear to the people listening that this is not available yet. This is very much a preliminary stage. We're just getting started. We have a lot more to do. But there is hope, and I think that's important right now to say, that there's alot of excitement and alot of hope that we may be really focussing at a different level of this language problem. And that might be helpful to us in the long run. AGAIN, DR. CARLA SHATZ, PRESIDENT OF THE SOCIETY FOR NEUROSCIENCE. Shatz: First of all, it's very exciting because it suggests that there will always be ways, even now, of helping children to learn to read who have difficulty. And secondly, it implies that there may be some kind of abnormal sets of connections within the brain that could perhaps someday be corrected, if we could understand how information and how this kind of timing information is being processed by the brain, in normal development in children. THIS RELATES TO ONE FINAL MILESTONE IN WHAT BRAIN SCIENCE CAN TELL US ABOUT OUR CHILDREN. IT'S QUITE STRIKING. TO SOME PARENTS, IT MAY ALREADY BE AS CLEAR AS THE PINKS AND BLUES WITH WHICH WE DISTINGUISH OUR CHILDREN. DO BOYS AND GIRLS THINK DIFFERENTLY? Lyon: Well, it doesn't take a rocket scientist to see that males and females behave differently. And it's not a stretch to then think about the fact that behavior is rooted in biological differences brain-wise. (Music) CLINICAL STUDIES SUGGEST THAT THE AVERAGE MALE BRAIN MAKES FEWER CONNECTIONS BETWEEN THE HEMISPHERES. IF A BOY SUFFERS AN INJURY TO THE LEFT SIDE OF THE HEAD, HIS BRAIN CANNOT EASILY COMPENSATE. IN THE FEMALE BRAIN THERE ARE MORE CONNECTIONS BETWEEN THE HEMISPHERES. SO GIRLS TEND TO RECOVER MORE EASILY -- ONE HEMISPHERE CAN COVER FOR THE OTHER. USING THE OTHER SIDE OF THE BRAIN, THEY MANAGE TO ACCOMPLISH THE SAME FUNCTIONS. THERE ARE OTHER SIGNS OF INHERENT DIFFERENCES BETWEEN THE BRAINS OF BOYS AND GIRLS. PERHAPS THE MOST SURPRISING COMES FROM THE YALE LABORATORIES OF DRS. SALLY AND BENNETT SHAYWITZ. THEY ASKED 19 BOYS AND 19 GIRLS TO PERFORM A SERIES OF RHYMING EXERCISES. THEY FOUND THAT BOYS AND GIRLS WERE EQUALLY SUCCESSFUL IN PASSING THE TEST. BUT MRI SCANS OF THE BOYS' BRAINS SHOWED THAT ALMOST ALL THE BOYS WERE RELYING ON JUST ONE SIDE OF THEIR BRAIN. THE GIRLS' BRAINS WERE ACTIVATED ON BOTH SIDES. READING IS AN ACTIVITY THAT SEEMS UNRELATED TO THE TRADITIONAL DIVISION OF LABOR BETWEEN THE SEXES. YET, IF MEN AND WOMEN USE DIFFERENT PARTS OF THEIR BRAINS TO READ, IT MAY BE A SIGN OF FUNDAMENTAL DIFFERENCES IN THE WAYS THEIR BRAINS ARE ORGANIZED. THE SHAYWITZ STUDY MAY ALSO HELP RESOLVE A QUESTION THAT HAS PUZZLED RESEARCHERS IN THE FIELD OF LEARNING DISABILITIES.
DR. REID LYON OF NIH EXPLAINS. BRAIN SCIENTISTS AGREE, THAT THE YEARS BETWEEN TWO AND TEN ARE THE CRITICAL PERIOD FOR TEACHING ANY HUMAN BEING MUCH OF WHAT HE OR SHE WILL NEED TO KNOW.
DR. MICHAEL PHELPS OF UCLA. (Ambience of kids returns) RESEARCH CONFIRMS WHAT MANY PARENTS ALREADY ASSUME: EXPOSING CHILDREN TO A VARIETY OF SIGHTS, SOUNDS, AND EXPERIENCES WILL PROMOTE HEALTHY DEVELOPMENT. A CHILD'S BRAIN NEEDS THIS KIND OF STIMULATION. SO, IF YOU HOLD YOUR CHILDREN, AND READ TO THEM, AND PLAY WITH THEM -- THEY WILL BE MUCH BETTER PREPARED TO TAKE ON THE CHALLENGES OF THE OUTSIDE WORLD. BRAIN SCIENCE IS ALSO OFFERING INSIGHT INTO WHAT MOST PARENTS HAVE BELIEVED FOR CENTURIES ABOUT CHILDREN -- HOW DIFFERENT THEY ARE FROM EACH OTHER. DR. MARTHA DENCKLA OF JOHNS HOPKINS UNIVERSITY. Denckla: I appreciate much more that people don't come in restricted varieties--smart people and dumb people. There are certain tests that I give...where I am ever so glad that I have the answer sheet and I am not the person on the other side having to give the responses... I guess it's a renewed sense of respect and excitement about individuals as individuals, about how no two people literally are really alike because of this tremendous diversity of the brain, and that the brain is like the face... And just as you can look at somebody's face, and say that person's most attractive feature is [pause], and that person's least attractive features is [pause], but the whole ensemble has its own unique flavor and the same is true about the brain. (Ambience of children/music) DR. PATRICIA KUHL OF THE UNIVERSITY OF WASHINGTON. Kuhl: Well, it's an amazing thing, as a scientist before you have children, you look at life in terms of these small pockets of experiments that you are conducting and you think you know very deeply about a principle that...that you've studied, and you do. But when you have a child, which I did about 8 1/2 years ago, you become aware that the piece that you're studying is such a little cog in a huge wheel. You know that's a truism, but repeated over and over again, and I think that the universal parental experience is amazement at the development of this child. They produce sounds and...and actions and become their own people so soon that you wonder what's going on in there. And it I think that the world view I have after having a child brings you back in to the laboratory with new vigor to try to understand how in the world does this come about? How does this experience that we're laying on the child, and we bathe them in language, we bathe them in culture. And they come out in a way that is very shaped by that experience. It's a sort of profound respect that you end up having of what we're capable of as human beings. (Ambience of baby returns/Music) DURING THE LAST HOUR, WE HAVE FOCUSSED ON THE CHILD'S BRAIN AND THE UNPARALLELED PERIOD OF LEARNING THAT HAPPENS DURING THE FIRST TEN YEARS OF LIFE... BUT, THE ADULT BRAIN IS MALLEABLE, TOO. NEURONS CONTINUE TO SPROUT NEW CONNECTIONS WHETHER YOU'RE FOUR YEARS OLD OR 40... BRAIN SCIENCE HAS MADE GREAT STRIDES IN THE LAST DECADE, BUT WE STILL KNOW RELATIVELY LITTLE ABOUT THE HUMAN BRAIN -- BY FAR, THE MOST COMPLEX STRUCTURE ON OUR PLANET. YET, WITH EACH NEW DISCOVERY, WE COME TO UNDERSTAND ITS REMARKABLE POWER AND ADAPTABILITY. IN PARTICULAR, WE HAVE RENEWED CAUSE TO MARVEL AT OUR CHILDREN -- FOR WITHIN THEIR YOUNG MINDS, OUR FUTURE IS BEYOND ITS INFANCY -- IT'S ALREADY TAKING SHAPE. I'M JUDY WOODRUFF Announcer: FOR A CASSETTE OR A TRANSCRIPT OF THIS PROGRAM , "GRAY MATTERS: THE DEVELOPING BRAIN"-- OR A FREE RESOURCE GUIDE OF: "DELIVERING RESULTS: A PROGRESS REPORT ON BRAIN RESEARCH" CALL 1-800-65-BRAIN. THAT'S 1-800-65-BRAIN. THIS PROGRAM WAS PRODUCED IN ASSOCIATION WITH THE DANA ALLIANCE FOR BRAIN INITIATIVES, AN INDEPENDENT ACTIVIST ORGANIZATION CREATED BY THE CHARLES A. DANA FOUNDATION IN 1993 TO CHAMPION THE PUBLIC STAKE IN BRAIN RESEARCH. ITS MISSION IS TO EDUCATE THE PUBLIC AND POLICY MAKERS ABOUT BRAIN SCIENCE RESEARCH AND ITS ENORMOUS POTENTIAL TO LIFT THE INDIVIDUAL AND SOCIETAL BURDENS OF BRAIN-RELATED DISORDERS AND DISEASES. TODAY, THE ALLIANCE BRINGS TOGETHER MORE THAN 140 NEUROSCIENTISTS, INCLUDING FIVE NOBEL LAUREATES. THE PRODUCERS WERE NOEL GUNTHER AND MARY BETH KIRCHNER. THE PRODUCTION ENGINEER WAS CHARLES LAWSON. PRODUCTION ASSISTANCE WAS PROVIDED BY MARY OLIVE SMITH, DEBORAH ROMANO , AND ZHAO XIO HUA -- WITH SUPPORT FROM DAN GEDIMAN , REBECCA GUNTHER, AND ELENA JORLING. SPECIAL THANKS TO DRS. CARLA SHATZ, KATHERINE BICK, AND GUY MCKHANN. PRODUCTION SUPPORT WAS GENEROUSLY PROVIDED BY WETA IN WASHINGTON, DC. (PRI Audio Logo) This is the fourth in the Gray Matters series. For more information about Gray Matters and the Dana Alliance for Brain Initiatives write to us at [email protected]
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