ADOLESCENT BRAIN DEVELOPMENT John Sexton Westchester Library System 4/7/09

Phineas Gage 1848

The natural development of different brain structures is an important source of behavior change in adolescents.” David Allen Walsh, Why Do They Act That Way? 2004

The Brain Stem Unconscious physiological functioning- breathing, heart beat Involuntary responses- reflexes, moving your hand away from a hot stove

The Limbic Brain The Amygdala The Hippocampus The Ventral Striatal The Hypothalamus

The Amygdala Plays a central role in the processing of emotions- the development in adolescence is characterized by emotional intensity and volatility. Decision making is based on emotions rather than reasoned judgment.

The Hippocampus The hippocampus plays a major role in encoding memories Increases in volume up to age 18 Is larger in females than males

The Hypothalamus The control center of the endocrine system which regulates hormones

The Role of Hormones Melatonin levels change which entices a change in sleep patterns. Leptin influences fat storage. In boys this influence is suppressed by testosterone which brings about a dramatic increase in muscle mass. Testosterone stimulates the amygdala. Levels in the body are twenty times higher for males than females.

The Role of Hormones Neurotransmitters have a large effect on mood. They include norepinephrine, dopamine, and serotonin. Estrogen and progesterone have a powerful influence on neurotransmitters which can cause sudden and dramatic mood swings.

The Cortex Conscious thought and reason The Prefrontal Cortex The Right and Left Hemispheres The Corpus Callosum- connecting the two hemispheres

The Prefrontal Cortex The brain’s executive or CEO Responsible for planning ahead, considering consequences and managing emotional impulses.

Blossoming and Pruning Blossoming-The brain develops in busts not in an even uniform way Pruning- some of our mental abilities develop not from adding of new synapses but from eliminating those that are weak and underused.

Myelination Myelin acts as insulation for the neuron’s axons. Axons that are not insulated with myelin are more prone to interference which causes messages to travel more slowly. An electrical charge that travels on a myelinated neuron travels one hundred times faster than on a non-myelinated neuron.

What can we do to help teens achieve positive brain development? Create opportunities to reinforce the use it or lose it principal. Create risk taking opportunities that have positive outcomes. Talk with teens about alternative possible decisions and their potential outcomes. It is important to listen to their point of view.

EMOTIONS Adolescents use the Amgydala (fight or flight response) rather than the Frontal Cortex (used by older adults) to read emotions Deborah Yurgelun Todd McLean Hospital Belmont, Mass (2004)

THE ADOLESCENT BRAIN Frontal Lobe Immaturity Could Translate Into: 1. Poor judgment and difficulty thinking through consequences of behavior 2. Increased risk-taking; inappropriate actions not as inhibited as in adults 3. Impulsive and emotional responses rather than logical and practical ones 4. Miscommunication with peers and adults—they miss subtle social cues, misinterpret expectations, and misread facial expressions. Phineas Gage 1848

THE ADOLESCENT BRAIN AND SLEEP Based on the Research of Dr. Mary Carskadon, Brown University Sleep Laboratory The average college student needs and young adults require 6-8 hours of sleep per night. Most get 5 or less. During adolescence there is a shift in their circadian rhythm or biological clock Melatonin levels peak around 11 p.m. to midnight. Ideal wake up time for an adolescent would be around 9 or 10 a.m.

MORE ON SLEEP *Purpose of sleep appears at least in part to be to review/rehearse things learned during the day. *Getting a good night of sleep after an important learning experience is critical to retention of material and learning (See Time “The New Science of Sleep” Dec. 2004) *Carskadon (Brown) and Wolfson (Holy Cross) sleep study (2000) *Ron Dahl (U of Pittsburg) and Eve Van Cauter (U of Chicago) study (2001) Sleep deprived youth experienced…. --elevated levels of the stress hormone cortisol (high bp) --impaired ability to process glucose (obesity and type 2 diabetes) --emotions less controlled and more exaggerated --increased depression and anxiety

Dopamine—brain chemical that creates a sense of well being WHY DO TEENS ENGAGE IN RISKY BEHAVIORS? Dopamine—brain chemical that creates a sense of well being During adolescence dopamine levels decrease in the nucleus accumbens (smaller subcortical area involved in pleasure response).”Adolescents have a built in urge to live on the edge,to seek thrills, to do things that will enhance chances of survival within the peer group.” Linda Spear—SUNY-Binghamton (2003) High levels of stress reduces dopamine levels. Addictive drugs increase dopamine levels and can damage the nucleus accumbens

Dopamine and Risk Taking Behavior The neurotransmitter involved in pleasure in the brain is dopamine. Dopamine is associated with both motivation and salience (recognizing when something is important). Reporting in Science magazine (2003)- dopamine neurons are most active when the prospect of a reward is less certain. Higher levels of uncertainty may be necessary to prompt activity of dopamine receptors in teens- which results in engaging in risk taking activities.

Teen Brains in the Library Consider your facial expressions Provide space where they can socialize, learn, play, read, engage and experiment. Provide structure and support. Understand they are under construction Remember, Search strategies are like algebra & logic, incomprehensible to the immature brain. Repetition is imperative.