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When Does Your Brain Stop Making New Neurons? Glimpses of A Cosmic Creation - f*r' , , I , ... , alk about . Surety the most ;" ~ (.~_/\\'-'" "."Z"'" J.\ Toutrageous notion ,".., ':.-----'- '- '[?\'. \\ in science is thai observa­ , _'''-- '(~~' I -. lions, measurements and ).~ ~< .' ", ,,- ..... -:- ~ .. brainpower can divine the i ~,.., -,'--'" ; -', I !( 'lr-J" t ~. 1 1/: origins of the universe. Yet , ,..~' • _,\oJ, beginning In me1960s, i" _,.,...... \ ,/ when asfronomefJ detect­ , ," c _.~ '. 'I ' ,'J' ed radiation that perme ­ ales the cosmos and ex­ ~:~, ''l'1 'i,~ I~/ plained It as the whisper , ~ . '-11' ". of a -big bang- thaI started t, .' . the universe. they have done Just that. · One of the most basic questions Is B where we come from and 42 YEARS OLD how we got here,· says physicist lawrence Krauss of Case Western Reserve BY SHARON BEGLEY encoding thoughts of someone who offered uncon­ University. "One of our HE SCIENTISTS ARE NOT SO NAIVE ditional and protection- a parent, a lover, greatest Intellectual tri­ as to tl'ink they have discovered a God, The goal was to induce the of security umphs Is realizing tha, the magic wand that can tum animosity that makes it more likely somcone will display, say, universe had a beginning.· into and into altruism and not selfishness. It worked, People be­ It occurred 13.7 billion benevolence, but the tarantula defi­ came more willing to give blood and do volunteer years ago, an explosion nitely raised their . Over the work, and less hostile to ethnic groups different that created all maner and Tyears psychologists Phillip Shaver and Mario from their own. Offered a chance to inflict on energy, plus space and Mikulincer had uncovered more and more evi­ an Israeli Arab with whom they were paired in an tlma themselves. The uni­ dence that people's sense of emotional securi­ experiment (serving him painfully spicy hot verse expanded from a very ty shapes whether they become altruistic or sauce), Israeli]ews did not dole it out as they hot. condensed ·singularl­ selfish, tolerant or xenophobic, open or defen­ djd without the security-circuit activation. 'Y"-thellkes of which cen sive. Once upon a time, that would have been They held back, And when they saw a young be found today In black holes. Particles sped away tha~ for whatever their roots such traits were woman distraught over having to pick up a on the expanding seas of thought to be, by adulthood, as hard-wired as tarantula as part of an experiment, they vol­ space-time, coalescing a computer's motherboard. unteered to take her place. Inlo galaxies and stars; But with the new millennium scientists were OK, so they didn't aU sign up to work in Darfur. somelimes a star uplod­ finding that brain wiring can change, even in But as recently as a decade ago, proposing that an ed, sprinkling the void adults. That got Shaver, a professor at the Univer­ adult brain could be rewired for compassion- or with aloms IhallYentual­ sityofCaJifornia. Davis, and Mikulincer. at Israel's anything else. for that matter- without experienc­ tv formed our bodies. We Bar-llan University, thinking: could they activate ing a life-altering would have been career ara stardust. The cosmos unused or dorman.t circuits to trigger the sense of suicide for a neuroscientist. Not anymore. Experts continues expanding, emotional security that underlies compassion and are overthrowing the old dogma that, by the ripe 115 galaxies like dots on benevolence? '!b find out, they gave volunteers old age of3, the human brain is relatively fixed in an inflating balloon. overt or subliminal cues to activate brain circuitry form and function. Yes, new memories could form, 74 new skills could be mastered and wisdom could (in some) be gained. But the basic cartography of the adult brain was thought to be as immutable as the HELLO, color ofyour eyes. This "neurological ," as psychiatrist Norman Doidge calls it in his recent DOLLY book, "The Brain That Changes ItseJr,' "spread Reproductive cloning through our culture, even stunting our overall view creates animals that are of human nature. Since the brain could not change, genetically identical 10 SHEEP, 1997 MOUSE,199B human nature, which emerges from it, seemed nec­ an existing one. Since Dolly makes headlines as Researchers In Hawaii essarily fixed and unalterable as well." 1997. scientists have the first clone of an adult creale 50 clones of a But the dogma is wrong, the nihilism groundless. cloned 17 species: mammal. single mouse. In the last few years neuroscientists havedismantJed it pillar by pillar, with profound implications for our view of what it means to be human. "These discover­ ies change everything about howwe should think of ourselves, who we are and how we get to be that way." says neu­ roscientist Michael Merzenich BULL, 1999 PIG,2000 of the University of Califor- Cloning a bull leads to a Five cloned pig1ets The first goal clone nia, San Francisco. ~e now debate about the safety of open the way to cloning dies from abnormal know that the qualities that de­ milk and meat from clones. animals to grow organs. lungdevelopmenl. Sne us at one moment in time come from experiences that shape the physical and func­ tional brain, and that continue to shape it as long as we live." The brain remains a work in progress even on so basic a GAUR,2001 MOUFLON ,2001 parameter as its allotment of RABBIT,2002 Awild ox becomes Asheep becomes the Researchers clone a neurons. For decades. scien­ the first clone of an first endangered-species rabbit that may model tists assumed that adding new endangered species. clone to survive infancy. human diseases. neurons to this intricate ma­ chine could only spell trouble, like throwing a few extra wires into the guts of your iPod. But in 1998 Peter Eriksson ofSwe­ den's Sahlgrenska Unh'ersity Hospital and colleagues dis­ covered that bmins well into their 60s and 70s un­ CAT,2002 MULE,2003 RAT,2003 dergo "neurogenesis." The new neurons appear in A company formed to Offspring of a horse Achallenge to research­ the hippocampus, the structuredccp in the brain reproduce cherished and a donkey yield ers, its eggs begin dividing that takes thoughts and perocptions and turns them pels clones the first caf. the first hybrid clone. almosllnslanlly. into durable memories. And studies in lab animals show that the new neurons slip into existing brain circuits as smoothly as the Beckhams onto the Hol­ lywood A list. Brain structure is also malleable, recording the footprints ofour lives and thoughts. The amount of neural real estate devoted to a task, such as playing AfIIICAN WIUlCAT, 2004 DOG,2005 WATER BUFFALO, 2005 the violin, expands with use. And when an area of Researchers use a Researchers in South Cloned in China, il opens the brain is injured, as in a stroke, a different re· domestic cal as its own Korea clone an Afghan in improving the gion-often on the mirror-image side-can take surrogate mother. puppy they name Snuppy. animal and Its milk. over its function. That overthrew the long-held view called "Iocalizationism," which dates back to 1861, when French surgeon Paul Broca linked the

WHATSHOULDWEALLKNOW? Uml) HORSE,2005 FERRET, 2006 WOLF, 2007 - WHAT MAKES APERSON CULTURAUYUTEAATE? AS II's Ihe first clone whose Researchers in Iowa South Korean scientists THEWURLD SEEMS TO GROW MORE COMPLEX BYTHEOAY. THE surrogate molher is also to use it to study human clone fWO gray wolves, QUESTION HAS TAXEN ON A SPECIAl URGENCY. CHECK OUT a genelic donor. respiratory diseases. an endangered species. ElCTRA.NEWSWEDI.COM FOR OUR TAXE ON OTHER SUBJECTS. un ro.wl, '" fllIflOIoI ""' -.. ... 'AI'UIII- KTn -.. .on -.mJIII-Km IIMIIU,II.1U1111-1nT1' 1tMII.I. I'ftr_ .uallD-wn' IMAGO l'ToUI 0ICIlINII0-tU0J_1ITlf1C .,IIIfITU ...... "., lIAILII- oUIIMAI,.I-a. Km IMMU. _1lM-Km --. .t.IIOTCIIoI.WJ_- 1I£1TT IM.I,5(I. 75 1U'I'l ..- IITTY ...... U'ITUIWaJ.IIl'U ;rm""""",r.wL.L~ 'MU.~II(IIII11Q11TY1[ - "WT!l "---'I(ITf_.trJ ability to speak to a spot in the left frontal lobe. But contrary to the belief that particular regions are un­ LINKS BETWEEN PAST AND PRESENT alterably wi.red for specific functions, even one as basic as the visual cortex cnn undergo a career Transitional fossils show the evolution of one group of organisms to another. Once called switch. In people who lose their sight at a young missing links, they have ancestral features of the older species as well as novel traits of the descendant. Among Ihe scores of transitional fossils scientists have discovered: age, the \1SUai cortex processes touch or sound or language. Receiving no signals from the eyes, the visual cortex snaps out of its ·waiting for Godol" funk and reactivates dormant wires, enabling it to perform a differentjob. 375 MILLION Ifsomething as fundamental as the visual COrtex YEARS AGO can shrug off its genetic destiny, it should come as little that other brain circuits can , too. A circuit whose hyperactivity causes obsessive-com­ pulsivedisordercan be quieted with psychothera­ py. Patterns ofactivity that underlie can be shifted when patients learn to think about their sad thoughts differently. Circuits too sluggish to perceive some speech sounds (staccato oncs such as the sound of"d" or "p") can be trained to do so, helping kids overcome dyslexia. For these and other TIKTAALIK RoSEAE -----' brain changes, change is always easier in , but the ,vindow ofopportunity never slams shut. This fish, unearthed on Canada's der and elbow, plus a proto-wrist, the fin From these successes, neuroscientists have ex­ Ellesmere Island and reported in 2006, could support the body and propel it on traeted a powerful lesson. [fthey can identity what has fins like ancestral fish, but its pectoral land . Its ribs and limb bones resemble fin contains arm bones like those In land­ those of later four-legged amphibians has gone wrong in the brain to cause, say, dyslexia, dwelling animals. With a bendable shoul - and other terrestrial species.

Maternal care can 150 MILLION an offspring's very DNA, YEARS AGO turning on some genes ARCHAEOPTERYX ---i----....,....~IIIJ . and silencing others. Discovered in Germany in they might be able to straighten out aberrant 1861, this first bird retains such dinosaur trails as a wiring, quiet an overactive circuit or juice up a long, bony tall and a full set 01 sluggish one. It won't happen overnight. But feeth. But it has birdlike wings UCSF's Merzenich believes we have glimpsed only and feathers. Its fingers are the surface of the ability of the bmin to change. less fused and more open than "The qualities that define a person have a neuro­ In modem birds. Paleontolo­ logical residence and are malleable," he says. "We gists have found nine fossils know that in a psychopath, there is no activation of the magpie-size creature, of brain areas associated with when he including one with a toe like sees someone . Can we change that? I a velociraptor's deadly claw. don't knowexact1y how, but I believe weean. I be­ lieve that just as you can take a 17-year-old and put him through basic training, inuring him to vio­ lence, we can take a person who is insensitive and make him sensitive to others' pain. These things that define us, I'm convinced, can be altered." Only more research- and it's coming- will reveal how easily, and how much. But what of the genes that shape our disposition and temperament? Here, too, malleability rules. As is often the case, this effect is easiest to detect in lab animals. Rats develop starkly different personali­ ties depending on how they are reared. Specifically, if Mom is attentive and regularly licks and grooms PAKICETUS them, they become well -adjusted little rodents, A descendant of ancient whales and an also adapted for life In the seas, with mellow and curious and non -neurotic mouse or ancestor of four-legged land mammals. paddlelike forelimbs, ears able to hear mL If Mom is neglectful, her pups grow up to be the first Pakicelus was found in Pakistan underwater and nostrils receding timid,jumpy and stressed OUL Once, this was at­ in 1981. 11 could move on land but was toward a blowhole position. tributed to the powerful social effects of maternal

76 care. But it rums out that Mom's ministrations can claim tfIa, God SClnored fos­ reach into the pups' very D A. Maternal How to Think sils throughout rock 1fnI!1 to silences genes for receptors in the pups' brains, make h look as If speda had with the result that they have few receptors and evotved over millionsof years. hen ce a hair-oigger stress response. MaternaJ care Like a Scientist God may have done that. bu1 keeps these genes on, so the pups' brains ha\re lots we'll newt" know and there ls umans have 23 pairs measures Ihe natural world. of receptors and a muted stress response. Lnatten­ no W8ylO disprove h. l" fhat of chromosomes con­ From lhose data it Infers the tive moms also silence the genes for estrogen re­ way, Is fundamentally 'aining abou, 20,000 empiricaJ laws that govern ceptors in their daughters' brains; the females grow H different from science. genes, DNA is the mokM::ule that physical and biological proc­ up to be less attentive mothers themselves. "It's al­ Despite the face it some­ canies hereditilI'f information esses. Explanations of large most Lamarckian ," says Francis Champagne of Co­ times presents 10 the world, In BYery living cell, maner Is classes of phenomena must lumbia University, referring to the discredited idea science is humble, recognizing made of atoms that are buitt of make testable predictions and that all findings are tentarive that offspring can pass along traits dlC)' acquire protons andlleUirons and be falsifiable . That Is, there (ahhough in many fields the during life. "But experiences during a lifetime are electrons and ... Alan leshner weigtlt of evidence would be passed on to the next generation." Isn', buying k. CEO of !he pretty tough to overturn) and Scientists are now beginning to see the first American Associalion for !he onty as good as the next exper­ glimmerings of this in people, too. Very young Advancement of Science, whtch iment. ttlabors to distingulsh children born with the form of a gene called publishes !he Journal Selenee true effects from random 5-HTI associated with usually are quiet and promotes science literacy, chance. Experiments have and introverted. But by age 7, scientists led by he agrees that people -need, at ·contro'- groups to make sure Nathan Fox of the University of Maryland find, minimum, a rough understand­ that an effect thOUght to come many are Ing of the core concepls of sci­ not. Only if the children have certai n ex­ from , say, taking a new drug periences- best guess: being raised by a stressed ence-the more the bener.­ does no' also show up In peo­ That woufd keep people from mother unable to provide emotional and physical pie who did nollake the drug. rejecting genellcally modiflOd protection-does the "shyness gene" live up to Good science di$linguish­ its billing. The molecular mechanism by which food because, as !hey ,ell poll ­ sters, it -contains genes" (aU IS COrTIMIton from causation. experiences reach down into the double helix and If kids who play ",len, video­ living cells do). must be a way 10 make an ob­ inhibit or elicit the expression ofa gene is not as games commit more violenca. clear in people as it is in lab rats. At least, not yet. The real problem today, servation that could disprove however, Is nol ignorance of the explanation. (Scientists before you blame the game But it's an early sign that we arc not necessari ly you'd bener be sure thaI ¥to­ slaves to the genes we inherit. lhe fact that Earth rewtves call that overarchln, explana­ around the sun once a year r~n a theory; the term does not lence-prone Idds are not more Few laypeople understand that neurological (something 25 percent of adult mean, as it can In everyday drawn 10 violent games than nihilism and genetic determinism have been so Americans do not know) . -It's parlance, somebody's off-the ­ other kids. tf so, then vi.nl discredited. Most still embrace the idea that our ,ha, poople don" undemand cuff guess.) The requirement behavior causes !he p1a~ng fate is written in our DNA, through the intermedi­ what fs and Isn't science, - says of faJsffiabilhy rules out super­ of ¥folent vfdeopmes. and ary of the brain wiring that D A specifies. "Ws leshner. natural explanations; you can­ not the otherway around. puzzling that determinism is so attractive to so Science observes and not disprove, for instance, the - S.8. many people," says UCSF's Merzenich. "Maybe it's appealing to view yourself as a defined entity and your fhte as determined. Maybe it's in our nature to accept our condition." There is an irony to that. When people believe THERAPEUTIC CLONING 101 Doclors believe stem cells produced through therapeutic cloning could one that their abiHties and traits are flXed, interven­ day be used to repair or replace damaged tissues all over the body. A look: tions meant to improve academic performance or qualities such as resilience and openness to new experiences have little effect. "But if you tell people Nerve cell th at their brain can change, it galvanizes them," says psychologist Carol Dweck of Stanford Uni"er­ • sity, whose 2006 book "Mindsets" explores the "Denud88tod" Bee Blood cell power of belief to alter personality and other O The nucleus of an traits. "You see a rapid improvement in things like egg cell-and the DNA II - con rains-Is removed, bUI ( motivation and grades, or in resilience in the face the egg remains inlacr. ofsetbacks." 'one of that happens, or at least not Brain clfl as readily, in people who believe they are stuck \\~th the brain they have. .:-R* This is not to say that everydling ,vi)) yield to Muscle cell the new brain science. There may tum out to be aspects of ourselves that resist every effort at A DNA transfer: The A Cuttivatinc atem cella: Chemicals Treatmont. The ~ nucleus of one of the pa­ • stem cells could then change, for which we may be glad. But for too V are used to activate Ihe egg. and O Ilent's body celis, whkh holds soon a small cluster of cells called a be grown inlo any of many decades, science sold the brain short. It is Ihe patient's genetic malerial, blastocyst forms. Cells 'rom this cluster numerous cell types and way too early in the battle against neum-nihilism is transferred 10 the egg. give rise 10 embryonk stem cells. used 10 Irealthe patient. to declare anything beyond the reach of the brain's potential to transform itselr. •

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