Brain Development in Brain Development in AdolescentsAdolescents

OCCJ Trialogue SeriesOCCJ Trialogue SeriesFeb 7, 2010Feb 7, 2010

Ovidio Bermudez, MD, FAAP, FSAM, FAED, CEDPOvidio Bermudez, MD, FAAP, FSAM, FAED, CEDPClinical Professor of Psychiatry and PediatricsClinical Professor of Psychiatry and Pediatrics

University of Oklahoma College of MedicineUniversity of Oklahoma College of Medicineandand

Medical DirectorMedical DirectorLaureate Eating Disorders ProgramLaureate Eating Disorders Program

800.322.5173 or 918.491.3702800.322.5173 or 918.491.3702www.laureate.comwww.laureate.com

QuizQuiz

Can you tell who this Can you tell who this is and what he is is and what he is known for?known for?

Alfred BinetAlfred Binet

In 1904 was commissioned by the French In 1904 was commissioned by the French government to develop a test that would government to develop a test that would differentiate “intellectually normal” from “lesser differentiate “intellectually normal” from “lesser students” to offer the latter special educationstudents” to offer the latter special education

Simon-Binet (IQ) testSimon-Binet (IQ) test

H.H. Goddard translated into English in 1909 H.H. Goddard translated into English in 1909 with the bias that “intelligence was fixed”with the bias that “intelligence was fixed”

Binet disagreed with this notionBinet disagreed with this notion

Measuring Change in the Measuring Change in the Developing Human BrainDeveloping Human Brain

Structural MRI to track changes in size and shape

of neuroanatomicalstructures with development

Functional MRI (fMRI) to track changes in brain and behavior with development

Casey et al 2005 Current Opinions in Neurobiology

A B C

Diffusion Tensor Imaging (DTI) to track strengthening of brain

connections with development

OutlineOutline

Growth and development of the brainGrowth and development of the brain– ChildhoodChildhood– AdolescenceAdolescence

From proliferation to pruningFrom proliferation to pruning

Sequential maturation of brain regionsSequential maturation of brain regions

OutlineOutline

Growth and development of the brainGrowth and development of the brain– ChildhoodChildhood

The BrainThe BrainMain componentsMain components– Gray matterGray matter

Neuronal cell bodiesNeuronal cell bodies

NeurophilNeurophil– DendritesDendrites– Unmyelinated axonsUnmyelinated axons

Glial cellsGlial cells

CapillariesCapillaries

– White matterWhite matter

Myelinated axon tracksMyelinated axon tracks

– Cerebrospinal fluidCerebrospinal fluid

The BrainThe Brain

Humans achieve their Humans achieve their maximum neuronal density maximum neuronal density between 3between 3rdrd and 6 and 6thth month month in uterusin uterus

During the last gestational During the last gestational trimester there is pruning trimester there is pruning of non-essential brain cellsof non-essential brain cells

The BrainThe Brain

In early childhood there is significant brain In early childhood there is significant brain growth (proliferation of gray matter), attaining growth (proliferation of gray matter), attaining 90-95% of adult brain size by age 6 90-95% of adult brain size by age 6

In the 6-12 year period there is a proliferation In the 6-12 year period there is a proliferation of inter-neuronal connectivity (“thickening” of of inter-neuronal connectivity (“thickening” of gray matter peaks at 11 for girls and 12-1/2 for gray matter peaks at 11 for girls and 12-1/2 for boys)boys)

OutlineOutline

Growth and development of the brainGrowth and development of the brain

– AdolescenceAdolescence

The BrainThe Brain

Until recently, and according to Piaget’s Until recently, and according to Piaget’s theory, it was thought that the highest rung theory, it was thought that the highest rung in the ladder of cognitive development was in the ladder of cognitive development was reached at about age 12 with the onset of reached at about age 12 with the onset of formal operational thinkingformal operational thinkingSome even believed that adolescence was Some even believed that adolescence was not a biological process but rather a social not a biological process but rather a social construct, artificially “invented” after the construct, artificially “invented” after the industrial revolutionindustrial revolution

The BrainThe Brain

““Adolescent behavior” is influence by Adolescent behavior” is influence by “raging hormones” and “underdeveloped “raging hormones” and “underdeveloped cognitive controls” needed for mature cognitive controls” needed for mature behaviorbehaviorIn addition, both hormonal effects and In addition, both hormonal effects and brain development play a role in illnesses brain development play a role in illnesses with onset in the teen yearswith onset in the teen years– Acne, body composition, certain malignanciesAcne, body composition, certain malignancies– Epilepsy, schizophrenia, bipolar disorderEpilepsy, schizophrenia, bipolar disorder

OutlineOutline

Growth and development of the brain in Growth and development of the brain in adolescenceadolescence– From proliferation to pruningFrom proliferation to pruning

The BrainThe Brain

Between age 12 and the early 20s about Between age 12 and the early 20s about 0.7% of the gray matter is pruned yearly 0.7% of the gray matter is pruned yearly (teens loose about 15% of gray matter)(teens loose about 15% of gray matter)““Neural Darwinism”Neural Darwinism”– survival of the fittest (or most used) synapsessurvival of the fittest (or most used) synapses

As this pruning occurs, white matter As this pruning occurs, white matter thickens enhancing the effectiveness of thickens enhancing the effectiveness of the neural connections that remain the neural connections that remain (possibly until the 5(possibly until the 5thth decade of life) decade of life)

The BrainThe Brain

The brain is gradually becoming more The brain is gradually becoming more effective (trimming connections but effective (trimming connections but enhancing processing speed and enhancing processing speed and effectiveness) but at the expense of effectiveness) but at the expense of loosing some of its ability to learn and to loosing some of its ability to learn and to recover from injuries like traumarecover from injuries like trauma

OutlineOutline

Growth and development of the brain in Growth and development of the brain in adolescenceadolescence

– Sequential maturation of different areasSequential maturation of different areas

The BrainThe Brain

Sequential development of different areasSequential development of different areas– 1st the 1st the posterior brainposterior brain

mediate direct contact with the environment by mediate direct contact with the environment by controlling such sensory functions as vision, controlling such sensory functions as vision, hearing, touch, and spatial processinghearing, touch, and spatial processing

– Next the Next the mid brainmid brainareas that coordinate sensory inputareas that coordinate sensory input

– Last the Last the anterior brainanterior brainprefrontal cortex, home of the executive functions--prefrontal cortex, home of the executive functions--planning, setting priorities, organizing thoughts, planning, setting priorities, organizing thoughts, suppressing impulses, weighing the consequences suppressing impulses, weighing the consequences of one's actionsof one's actions

In summaryIn summary

The brain “proliferates” from birth to age 6 by The brain “proliferates” from birth to age 6 by increasing gray matter and from 6-12 by increasing gray matter and from 6-12 by increasing inter-neuronal connectivityincreasing inter-neuronal connectivityThen, fine tunes from 12 to about 20 through Then, fine tunes from 12 to about 20 through “pruning” of less used connections. The pre-“pruning” of less used connections. The pre-frontal cortex being the last to fully “come on frontal cortex being the last to fully “come on line”line”Full brain maturation is final by about age 25 Full brain maturation is final by about age 25 (perhaps a little earlier in females)(perhaps a little earlier in females)However, the brain in changing throughout our However, the brain in changing throughout our lifespanlifespan