Inside the Inside the Teen’s Brain:Teen’s Brain:What Makes Teens Tick?What Makes Teens Tick?

Ann Tilton, MD

Based on

Primal TeenBarbara Strauch

Crazy by DesignCrazy by Design

• Why do they do what they do?Why do they do what they do?– HormonesHormones– FriendsFriends

–My fault……My fault……– BrainBrain

What is going on?What is going on?• Prior thoughts:Prior thoughts:

– Brain was finished/cookedBrain was finished/cooked– 11stst 3 years are the most important 3 years are the most important

• NOT SONOT SO

• Now: Now: – Dramatic transformationDramatic transformation– Stumbling blockStumbling block

• Relatively few dieRelatively few die• In animals “over in a blink”In animals “over in a blink”

StudyStudy

• NIH- Jay GieddNIH- Jay Giedd– 500 kids MRI for normals500 kids MRI for normals– Found the gray matter was thickening Found the gray matter was thickening

and then thinning and then thinning (Nature and Neuroscience)(Nature and Neuroscience)

– AreasAreas• Parietal lobesParietal lobes• Temporal lobesTemporal lobes• Frontal lobesFrontal lobes

What is Normal?What is Normal?

• Frontal lobes synapses- Frontal lobes synapses- – by age 2 exceed adult levels 2X and by age 2 exceed adult levels 2X and

adult level by 16-17- adult level by 16-17- HuttenlockerHuttenlocker

– Confirmed by Chigani based on PET Confirmed by Chigani based on PET – More is not necessarily better More is not necessarily better (fragile X)(fragile X)

• Prefrontal cortex develops until Prefrontal cortex develops until adulthoodadulthood

• MORE MORE vunerablevunerable if exposed if exposed

Altered StatesAltered States

• EnrichmentEnrichment– Rats in a more complex environment Rats in a more complex environment

have thicker cortex – have thicker cortex – increased dendritesincreased dendrites

• DeprivationDeprivation– Romanian OrphansRomanian Orphans

• Chigani - Less active in limbic area (facial Chigani - Less active in limbic area (facial recognition and attachment)recognition and attachment)

Age of ImpulseAge of Impulse• Beat the TruckBeat the Truck

• InternetInternet

• Irresistible urge……Irresistible urge……

Age of ImpulseAge of Impulse• Pre frontal cortexPre frontal cortex

– Limbic- gut and emotionLimbic- gut and emotion– Separates humansSeparates humans

• 29% growth29% growth• Chimps 17%, cats 7%Chimps 17%, cats 7%

– The great Inhibitor- teens are capable but The great Inhibitor- teens are capable but do not have the do not have the breaksbreaks

– Parents need to be the teen’s “frontal Parents need to be the teen’s “frontal cortex”cortex”• In some cultures the child is an adult at 12 In some cultures the child is an adult at 12

– ( in a very ordered society)( in a very ordered society)

Making ConnectionsMaking Connections

• Myelin jumps 100% in teen yearsMyelin jumps 100% in teen years– Good and badGood and bad

• Growth especially in the cingulate Growth especially in the cingulate gyrus and hippocampusgyrus and hippocampus– Gut reactionGut reaction

• Calm down-Calm down-– Decreased Glutamate Decreased Glutamate

Making ConnectionsMaking Connections

• World is seen differentlyWorld is seen differently– fMRI – Yurgeleu-ToddfMRI – Yurgeleu-Todd

• Teen sees a picture of fear in a faceTeen sees a picture of fear in a face– SEES ANGERSEES ANGER

– Social cuesSocial cues• Do not get it rightDo not get it right

Adolescent AnimalAdolescent Animal

• Rhesus monkeyRhesus monkey– Monkeys are better if raised by nurturing Monkeys are better if raised by nurturing

mothers and terry cloth mothersmothers and terry cloth mothers– Peer-raised have loose attachmentsPeer-raised have loose attachments

– The males mature later – protectiveThe males mature later – protective• Shy and offensiveShy and offensive• Middle schoolMiddle school

Wake UP!!Wake UP!!

• Melatonin surges 2 hours laterMelatonin surges 2 hours later

• Adults respond by: Adults respond by: having them go to bed early and start having them go to bed early and start

school earlierschool earlier• Sleep loss leads to:Sleep loss leads to:

– AngerAnger– SillySilly– Increased emotionIncreased emotion

Risky Business-Risky Business-Why do they do what they Why do they do what they

do?do?• Most do a few stupid thingsMost do a few stupid things

– Normal & necessaryNormal & necessary– RiskyRisky

• 20% of 720% of 7thth and 60% of 11 and 60% of 11thth graders have had graders have had sexual intercoursesexual intercourse

• 10% drank weekly10% drank weekly

• Probably not “immortal” - just their Probably not “immortal” - just their own logicown logic

Risky Business-Risky Business-Why do they do what they Why do they do what they

do?do?• Neuroscience of riskNeuroscience of risk

– Use prefrontal cortexUse prefrontal cortex

• Thrills:Thrills:– Dopamine-Dopamine-

• Smooth movement and Pleasure – Reward Smooth movement and Pleasure – Reward circuitcircuit

• Increased inIncreased in– VideogamesVideogames– Addiction / drugsAddiction / drugs

THRILLS!!!THRILLS!!!

• Novelty seekersNovelty seekers– 50% heritable – Kennedy legacy50% heritable – Kennedy legacy– High – sensitive to rewardHigh – sensitive to reward– Low- safe except with alcoholLow- safe except with alcohol

• Dopamine decreases from childhood Dopamine decreases from childhood (except pre frontal cortex)(except pre frontal cortex)

– Teens are depletedTeens are depleted

THRILLS!!!THRILLS!!!

• AddictionAddiction– Drugs - cocaine, heroin, nicotine, Drugs - cocaine, heroin, nicotine,

alcohol alcohol all increaseall increase dopamine dopamine• Overload down regulates dopamineOverload down regulates dopamine

DrugsDrugs

• AlcoholAlcohol– Alcohol in Adolescents is less sedatingAlcohol in Adolescents is less sedating– 50% alcoholics traced to a gene related to 50% alcoholics traced to a gene related to

the reward system – dopamine, serotonin, the reward system – dopamine, serotonin, and endorphinsand endorphins

DrugsDrugs

• AlcoholAlcohol– RatsRats

• Damage to the hippocampus 10% smallerDamage to the hippocampus 10% smaller– With 2 drinks per day With 2 drinks per day

– More Problems with stopping drinkingMore Problems with stopping drinking• With alcohol the NMDA-glutamate receptors are With alcohol the NMDA-glutamate receptors are

blocked – then more sensitiveblocked – then more sensitive– Too much calcium is let in - cell suicideToo much calcium is let in - cell suicide– Death in the hippocampusDeath in the hippocampus

DrugsDrugs

• AlcoholAlcohol– Worse for teenagersWorse for teenagers

• 2 drinks a day leads to 10% memory loss2 drinks a day leads to 10% memory loss

• Heavy drinkers (5 drinks in a row at least 1X Heavy drinkers (5 drinks in a row at least 1X in 2 weeks)in 2 weeks)

– 30% 1230% 12thth graders graders– 26% 1026% 10thth graders graders– 14% 814% 8thth graders graders

DrugsDrugs

• AlcoholAlcohol– Worse for teenagers who drink Worse for teenagers who drink before before

15yr15yr• 5X more likely to be a heavy drinker5X more likely to be a heavy drinker• 10X more likely to be involved in a fight10X more likely to be involved in a fight• 7X more likely to be in a car wreck7X more likely to be in a car wreck

SmokingSmoking

• Smoking and PanicSmoking and Panic– If smoke 15X risk of Panic attacksIf smoke 15X risk of Panic attacks

• Nicotine mimics ACHNicotine mimics ACH– Esp in the ventral tegmental area where Esp in the ventral tegmental area where

there are many neurons that produce there are many neurons that produce dopaminedopamine• Produce 2X the number of receptors = leads Produce 2X the number of receptors = leads

to cravingto craving

SmokingSmoking

• Females Females – are more susceptible due to estrogenare more susceptible due to estrogen– Hippocampus damageHippocampus damage

• AllAll– Lower serotonin levels which lead to Lower serotonin levels which lead to

depressiondepression– Prone to infectionsProne to infections

SchizophreniaSchizophrenia

• Theories:Theories:– Abnormality of Dopamine and GABAAbnormality of Dopamine and GABA– Normally loose 15% of excess cortical Normally loose 15% of excess cortical

gray mattergray matter• Problem with pruning- Schizophrenics Problem with pruning- Schizophrenics

loose 25%loose 25%

– Prefrontal cortex abnormalitiesPrefrontal cortex abnormalities

ConclusionsConclusions

• Science continues to show Science continues to show behavior and brain structure behavior and brain structure dance in tandemdance in tandem

Thought…..Thought…..

The Chinese symbol for The Chinese symbol for ChangeChange is is

both Peril and Possibilitiesboth Peril and Possibilities