Adolescent Brain Development: A Key to Behavior Jordan Greenbaum, MD Stephanie V. Blank Center for Safe and Healthy Children Children s Healthcare of Atlanta Outline • 
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What do we know about adolescent behavior? Early brain development Adolescent brain development Effects of adverse childhood experience on brain development What do we know about adolescent behavior? •  More self-­‐aware and self-­‐reflecMve than children •  Develop improved –  Working memory –  SelecMve aOenMon –  Problem-­‐solving What do we know about adolescent behavior? behavior •  Show increased risk-­‐taking •  Impulsive behavior •  13,000 adolescent deaths in U.S. annually, related to injury •  SubopMmal choices and acMons (Casey et al) disMnct from childhood and adulthood Adolescents may not be good at…. •  Suppressing inappropriate thoughts/acMons •  Favoring goal-­‐directed behavior •  Delaying graMficaMon He knows beOer, but does it anyway!!! Neural Circuits •  MaturaMon –  Growth of dendrites –  Growth of axons –  Synaptogenesis –  Pruning –  MyelinaMon •  Use it or lose it 6
Brain MaturaMon •  Genes interact with environment •  Diet, toxins, experiences impact brain architecture and funcMon •  LocaMon is everything •  SensiMve periods Adolescent Brain Development •  MRI evidence suggests –  Major physical changes in adolescence –  White maOer and gray maOer differ in course of development –  Different areas of cortex mature at different rates White maOer change Gray maOer change with age With age Giedd, JN, et al. Nature Neurosci, 1999. Gogtay, et al, Proc Nat Aca Sci, 2004 Age-­‐Related Refinements •  Evidence from fMRI studies suggests –  More diffuse, less efficient acMvaMon of frontal cortex in children –  Adults showed acMvaMon of smaller area –  Changes correlate with improved task performance Blakemore, Choudhury, J Child Psychol Psch 2006 Prefrontal Cortex (PFC) •  Self regulaMon •  EmoMonal regulaMon •  ExecuMve funcMoning •  Interacts with amygdala www.humboldt.edu/~morgan/pre3_s05.htm
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Amygdala •  Roles –  Processing emoMons –  IdenMfying emoMon related to facial expressions –  EvaluaMng emoMonal significance of sMmuli –  Assessing threat –  IniMaMng stress response •  Regulated by hippocampus and prefrontal cortex www.tpub.com/.../14263/css/
14263_203.htm Nucleus Accumbens •  Important in processing –  MoMvaMon and Reward –  Pleasure –  Aggression, fear •  Role in addicMon •  Communicates with PFC, amygdala and other regions Back to Behavior •  Control over impulsivity –  Linear development –  Related to gradual, prolonged development of PFC •  Changes in risk-­‐taking behavior –  Nonlinear, development –  Related to changes in subcorMcal structures (including amygdala and accumbens) A Neurobiological Model For Adolescent Brain Development •  Must consider both limbic (emoMonal) and prefrontal (execuMve) regions •  Regions develop at different rates •  Adolescent biased toward limbic influence •  Adolescents may understand risks, but sMll take them Casey et al, Ann NY Acad Sci 2008 A Neurobiological Model Limbic Development Prefrontal Development Adolescence Casey et al, Ann NY Acad Sci 2008 A Neurobiological Model For Adolescent Brain Development Increased responsiveness to rewards (accumbens) + Immature behavioral control (PFC) Increased risk-­‐taking behavior, emoMonal reacMvity Casey et al, Ann NY Acad Sci 2008 What Are The ImplicaMons? •  Immature adolescent brains & Adverse effects of toxic stress: –  Are adolescents responsible for their harmful acMons? –  When should we start holding them accountable? –  What about individual variaMon? –  How much can good parenMng and posiMve experiences influence brain development of adolescent? –  How much are adolescents vicMms of their environments? Contact info: Jordan Greenbaum, MD 404-­‐785-­‐3829 [email protected]