Januari 02, 2017
(whoosh and beeping) (electronic music) - i tend to get unsolicited feedback, such that should be a very short talk. (audience laughing) isn't that a contradiction of terms. you mean they found one. and there's like a book amonth that sort of piles on these unflatteringportrayals, the primal teen,
that's actually not toobad, but mom, i hate you, get out of my life, but firstdrop cheryl and i at the mall. now i know why tigers eat theiryoung is right to the point, yes, your teen is crazy. but with the technology suchas magnetic resonance imaging, we can for the firsttime look under the hood of the living, growing brain. and what we've found is thatnot only do teens have brains, (audience laughs)
but they're good brains, they're as they shouldbe, they're not broken. and i'd go so far as tosay if they weren't the way that they are, we wouldn't even be here. and evidence from that comesfrom kind of unlikely source i'll get to in a minute. so the teen brain's differentthan the brain of a child, it's different than the brain of an adult, it's not just half way between,
it's kind of its own distinct entity, and it's been exquisitelyforged by evolution to have certain features. behaviorally, the big threeare increased risk taking, increased sensation seeking, and a move away from parents to peers. and i think these are deeplyrooted in our biology, because it's not just humans, all social mammals havethese three features.
and so we're probablyfighting mother nature by trying to eliminate these. and this is always veryspeculative to argue these ways, but one idea is that ithelped us get out of the home, which is a really irrationalthing to do, okay, why, people loved us,they feed us, protect us, it's a good gig, right? but it turns out it works better if we do. less inbreeding, it justsort of, you know, morally,
right around, it just worksbetter if this happens. and so these features,they involved at a time without firearms, withouthigh-speed motor vehicles, without designer drugs and stuff, so some of these issues arekind of this stone age brain in computer age world aspect. but i think that thesebehaviors have virtues as well. when i was at the nih,the smithsonian museum, sort of close, they had this exhibit,
the hall of human origins,which i really liked, but kind of not strictly featured a little placard on the floor,looked at the relationship between brain size and climate change. and the last big increase in brain size 500, 800,000 years ago. but what i thought was intriguing was that what was correlated wasthe change in climate, not the degree.
before seeing this i thought,yeah, it got really cold, you had to be supersmart justto stay alive long enough to get food and reproduce. but this is subtlety different. everybody in this room had ancestors whose brains were good at adaptation. and we're really good at it in terms of, even compared to our quiteclose, genetically close, rather in the neandertrumps,or neanderthals,
i'll pause, we can edit that later. (audience applauds) we can tell enormous amounts from teeth and fossilized teeth, whichactually we've done it. everybody's teeth right noware fossils, calcified cells. but they work like treesso they have rings. so tree rings, this was a wetyear, a good year of growth, the rings are wider. and across many different species,
the rings get closer andcloser as you mature. the rings stop and you're done growing, it's done maturing. and so when you findthese fossilized teeth, if you find a fossilizedneanderthal tooth of a 12-year-old, and then check the rest of the cave, he's gonna be with hischildren, not his parents. and this is often portrayedas surprisingly rapid growth in the neanderthals.
but i think that's thewrong way to look at it. what's surprising isour protracted growth. we're the outliers, by far, it's one of the mostdistinctive things about us. and even across like crowsand many other species, the longer you're underprotection of your parent, the more complicated your food gathering, your communication, problem solving. crows are actually reallysmart as an example.
but similar crows, insize and, that don't have this protected maturation, don't have those abilities as well. it doesn't work to just keep your kids at home until their 40. i don't think on an individualbasis it doesn't work, but it's an intriguing trade-off i think that we keep options open, wekeep our brains changeable, see what the environment's gonna be like.
we can live on the north pole,we can live on the equator, or everywhere, we can even live in outer space for a little while with technologies thathave been developed. and so this is a good thing, i think, in terms of this abilityto keep options open for a long time, but it'sreally being put to the test with the digital revolution. and this is, just in my
short career is a game changer. the way that we interactwith like what we're doing at this moment with onesand zeroes and the lights, the projector, it's changed everything, it's changed the way that we learn, content that's on internetand the greatest minds on the planet are a clickaway, you know, for free. it's just amazing, it's magical. the way that we play and the way
that we interact with each other. and so i've been fascinatedby this interaction in terms of the biologyof this changeability and the technologies that have taken over in a sense, so, of almost 11 hoursa day of screen time, and 30% of that time more than one device. and so the usual questionis is it good or bad or that's the wrong question, right,
almost any interestingquestion is it depends in terms of in what waysand how it depends and what it depends upon. but i think that this is an opportunity in terms of to influence adolescents. one of the tragedies ofmy profession is that it's almost a 10-year gap between onset of illness and treatment. we need to do better.
and i think perhaps thetechnologies can help us get there in terms of by monitoring thingslike social media activity, maybe even just movement, gps data, harnessing these technologies in an ethically appropriate way to help us recognize mental illness so that we can intervene while the brain is still more changeable. and so a lot of the debatesaround this that there's
it's just not natural, right. we evolved to talk to eachother, to be with each other, to share smiles and touches and every, and now we're looking at screensfor a big part of the day. but a kind of argument to that is reading's not natural either. reading's only about 5,200 years old. so most humanity, nobody read. so i don't think that byitself is a good argument.
it kind of makes the pointthat the whole aspect of this is the changeability. 10,000 years ago hunting,gathering berries, it's the same brain in terms of that's a blink of an eyein evolutionary terms. but our brains are amazing. we can adapt, you know, a lotof us spend a lot of our day with symbols, you know,words, and that's so different than you know, what our ancestors did.
and so my career's basically been this in terms of trying tounderstand this plasticity in terms of how to optimizethe good and minimize the bad. and this kind of, how do you help people with mental illness is the fundamental question. and so kind of that notionof like what do we know? how do we know what we know? what don't we know?
why don't we know? that, but, you know, my first assumption isthe brain's involved. i hope so. it's like a spleen or something, i'm gonna feel like acomplete fool down the road. but i think, you know, it'sa reasonable assumption. and professor jernigan began this journey, b.j. and i started together at nh
and following down that pathof looking at the brain, and how the brain changes in both typical developmentand in illnesses. it's kind of a noncreative,started to design, actually, but scan kids, youknow, when they're young and follow them as they go through life, see how they're doing at school, at home, see what sort of influenceson the brain for good or ill. and at the nh, we did about 10,000 scans
of half the kids healthy, half the kids with different illnesses. and what we found were, it's nuanced, but likethe brain doesn't mature by getting bigger and bigger. by first grade it'salready 93% adult size. it matures by being moreconnected within itself and more specialized. and this idea of being more connected,
there's many ways you can approach this, but white matter is one of them. so, this insulating materialthat you get one to 2% more of into the fourth or fifth decade, the brain is able to communicateamongst itself faster. it's not very subtle, it's like 3,000-fold increase in bandwidth i think underlies a lot ofthe remarkable behaviors that we can do.
but it's not just a matterof maximizing speed, it's all about the timing. and so the fire togetherwired together the meaning, the information's in these patterns. but more and more we're understanding that that's the progression. if we look at different parts of the brain like letters of the alphabetas you go from an infant to child latency, teenagers,emerging adulthood,
that these letters become words,the words become sentences, the sentences, you know,paragraphs, metaphorically. and this all goes up in adolescence. the brain, no matter how you measure it, whether the molecular, eeg, blood flow, it becomes more connected. and this is kind of a fresh look in terms of this idea of graph theory networks, it gives us a whole new look.
so, for something like schizophrenia, before we'd be like, is this chunk bigger or smalleror different shape or size? but looking at the samemri scan, the same data, and looking at how it's interconnected, then we can discern old fromyoung, healthy from ill, 'cause their brain, not perfectly, but it's reallyexciting for someone like me i can't do the math, butto be a consumer of it
in terms of that, by looking at this connectivity, it gives us a whole newperspective on these illnesses. the other processes,the gray matter process and the one-two punch isoverproduce and then war, or fight it out. it's almost all complexityin nature arises, engine of evolution, overproduce something nonrandom selection.
and it has great potential. so it's constantly on-going, it's not like you onlyoverproduce during childhood and only prune during adolescence, but that we see thisupside down u-type of curve where as we specialize, thebrain actually becomes smaller. so after around 10, 11, 12,your brain doesn't get bigger, it gets smaller, but leaner,meaner, more specialized based on what you're demanding of it.
but it's not all parts equal. the prefrontal cortex involvedin controlling impulses, long-range planning, it'sparticular late to settle down. some, you know, 25 to 30, and that combined withthe hormonally-activated, puberty-activated limbicsystem, the passions of words, this imbalance creates a lot of the specials of teen behavior aspects. but again, this is how it should be,
if the prefrontal cortex is already done like 11 or 12 and stuff, thenwe wouldn't be as adaptable. and so i think this is thetension or the trade-off. the other place to start in terms of that is illnesses happen at different times. not perfectly, there's always variation, but alzheimer's doesn'thappen when you're three, and autism doesn't start when you're 60, that characteristically certain illnesses
tend to emerge at certain ages. and that's puzzling,you know, why is that? in terms of. and when you start looking at this, so much happens inadolescence, not a lot, most. it's up to 75%, and i still don't know the answer, that's been for 25 years,and we're like why? because the early answer isoh, teenagers are stressful,
it's a stressful time of life. you know, kids have theirparents killed in front of them, or they're starving to deathor there's war in 20 countries, enormous stresses, but theydon't get schizophrenia. and so that never rang true. and i still don't know the answer to this, why do things happen when they do? and so just one exampleis for schizophrenia, all of the findings yousee in adult schizophrenia,
you can predict what if typicalteen changes went too far? it's not causal, theyalready had schizophrenia, but so far withoutexception, in terms of both the mri changes, but alsothe molecular changes, and so it's just thispoint, it's intriguing. it doesn't help me helpfamilies with schizophrenia, but i think these are the kind of clues that we're starting to understand. so, in this specialization process,
in typical development, it'sabout 7% from ages 12 to 17, in schizophrenia, 28%. so it's not subtle. you know, four-fold difference. and so, understandingthe typical development, i think, is key, but abouthalf of what i deal with as an analyst isn't illness. all right, pregnancy is not anillness, but it's a big deal. relationships, caraccidents, incarcerations,
you know, life decisions, thishappens during adolescence. and it's frustrating as a physician, it's like there's noinsurance forms to check in terms of for these very real issues that aren't an illness. and this kind of notion is the glass half empty or half full? because this changeabilitycould be a great opportunity, making it even more tragicthat we aren't recognizing
the illnesses when they occur. and my final sort of analogyis to use michelangelo in terms of this is a veryfamous painting of his that by design should look like a brain, a cross-section of the brain, he, no, he wrote about it himself and stuff, and it's sometimes calledthe original synapse, you know, the. but it's not like that,
it's much more like his otherexpression of art, sculpting. we start with this block of marble, and life experiences and so, then we eliminate part. so we might be born withdifferent chunks of marble, sizes from genetics, you know, but within each, if weknew what we were doing, if we could guide this process, you know, there's masterpieces.
and you know, i think almost everybody. we don't know very, we don't know what we'redoing yet very well. and it's like most ofthe illnesses emerging less than 1-1/2 % of thefunding has been adolescence, until now finally, now,we have this project, that for the first time isgoing to really do this right. 11, 12,000 kids, 19sites across the country to understand what matters.
how does the brain growin health and illness, looking at, you know, everythingwe can think of, frankly, in terms of influences on this. i'm gonna brag for sandiego a bit in terms of there's these 19 sites across the country, but the coordinating centerfor the quantitative core and the neuropsyche corecoordinating all the centers are both here in san diego as well. what a good deal for us,you know, in terms of
the opportunities to try to understand what matters in teens' lives. and so the technologiesis a big part of it, how can we get a better sense of internal and external environments with the sensors, with devices they're already using, already wearing. 'cause this is the crossroads in life. this is where people make big decisions
about their direction in life. and there's this kind of notion that teens are messed up andthey're misguided and stuff, and it's dangerous. and i feel bad, 'cause i've, oh, i see. i don't know, peoplewill be honest with me. but this is in the crossroads. and what happens is even teens themselves
buy into this, right? and like stereotype, thread and stuff, if you think that you're, you know, not capable andstuff like that, it matters. most teens do well, you know,they'll get through this, they'll do well. but i think we do a disserviceby selling them short and i think that wereally need to recognize the huge upsides of this,much more than the downsides
that if we can figure out whatwe're doing, what matters, we can really make a big difference. thanks.
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