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A circuitous journey “to and through” the TEEN BRAIN “If Abraham’s son had been a teenager, it wouldn’t have been a sacrifice.” ---Scott Spendlove
The age-old question:“What’s the matter with kids today?” • The age-old answer: “Nuthin’—they’re just kids…”
How much embryology did I get in Nursing School? Hmmm…the sperm meets the egg…and then… Embryology
Yes, the sperm DOES meet the egg, but let’s quickly dispel a long-standing myth… • MYTH: The sperm is the aggressor The egg is passive.
The sperm is passive The egg sends a signal telling the sperm how eager she is to meet him and which Fallopian tube to swim up Not. The egg is 1,000x bigger than the sperm—the egg is the aggressor
Which way do we go, George? Which way do we go? Freshly ejaculated sperm has absolutely NO IDEA which way to swim
The Y-carrying sperm and the X-carrying sperm • The sperm carrying the Y chromosome is the faster swimmer…this explains why: • Male embyros outnumber female embryos by ~115 to 100 • Why do they swim faster than the sperm carrying the X chromosome? • The sperm carrying the Y chromosome is much lighter than the sperm carrying the X chromosome • The sperm carrying the X chromosome is HEAVY
Let’s head back to the womb… • Sexual differentiation in the embryo can “go either way” until the 8th week of gestation • The Sry region on the Y chromosome kicks in • The boy starts producing testosterone from the testicles; girls?? • Mom sends adrenal androgens across the placenta for both boys and girls, so… • Boys get 2 hits of testosterone; girls 1 hit
Clinical implications • Development of the brain en utero—testosterone influences communication patterns, behavior and the limbic system, as well as the basal forebrain and cognition • Boys receive a double hit of testosterone to the limbic system—influencing the fight/flight (assertive/aggressive) response; libido and sexual function
In fact… • Many pregnant moms say they “KNOW” it’s going to be a boy…kicking and tumbling…more active and aggressive en utero
Testosterone and sex drive • The area of the limbic system responsible for sex drive in the male is double the size of the area in the female
And then a 3rd hit of testosterone during puberty!! • The testicles kick in! • Puberty kicks in, testosterone levels increase 10-fold and sex becomes an obsession • Teenage boys think about sex about every 52 seconds
Testosterone in the female brain • Communication areas—verbal areas are larger; women on average, talk and listen a lot more than men; Pathways mature faster • Girls tend to speak earlier than boys; by 20 months we have double or triple the vocabulary; speak faster (250 wpm/125); • 20,000 words per day vs. 7,000 in boys • In colonial times, women were punished for the crime of “talking too much”
The anatomy of the teenage brain • Since the brain reaches its full size by age 5, it was assumed by most of the scientific community that the brain was fully wired by the end of childhood and that subsequent wiring only involved “fine-tuning” • WRONG assumption. • Let’s take a look at the various areas of the brain.
The prime real estate of the brain—the frontal lobe • The prefrontal cortex • The motor association area • The motor cortex • Broca’s area—voluntary speech and communication • (the last 2 areas are well-developed in early adolescence, however the prefrontal cortex and the association areas are immature in teenagers and continue to develop into their early 20s)
So, what is the prefrontal cortex? • It’s the center for judgment, insight, reasoning, organization, future planning and problem solving, and it has extensive connections with the emotional and instinctual centers in the limbic system, especially the amygdala. These levels are critical for emotional learning and high-level self regulation.
An easier way to put it…it’s your MOTHER! • And MOM is inhibitory---what’s the only word a MOM needs to know? • NO.NO.NO.NO.NO. • Socialization • She puts the checks and balances on behavior—especially on the amygdala—the wild beast within (the instinctual nucleus of the brain) • Parents, who act like parents, do this for teenagers; parents who act like teenagers, do not
The anterior cingulate gyrus of the prefrontal cortex • Weighs options, makes decisions • The worry-wort center—larger in women than in men • Girls brains mature faster; pruning starts earlier than boys; girls move more quickly toward maturation of all brain circuits and mature 2-3 years earlier than boys
Pruning the way to a mature brain • Neurons and synapses proliferate in the prefrontal cortex in childhood and preadolescence and they are they gradually “pruned” throughout adolescence • Eventually more than 40% of all synapses are eliminated, largely in the prefrontal cortex and association cortex
Dr. Peter Huttenlocher—University of Chicago • Opened the door to understanding the brain’s “plasticity” • made a big splash when he reported findings on how the number of synapses change from prenatal to adolescence • Found that at times, synapses were forming in a new brain at the incredible rate of 3 billion/second • 28 week old fetus—124 million connections • Newborn—253 million • 8 months—572 million • 10 years—500 million • 12 years—354 million • Pruning disorders? Schizophrenia? Bipolar? Autism?
Neuronal dropout over the first 21 years • It’s not just pruning • Neuronal dropout as well throughout the brain • # of neurons at birth; • # at 21; • # at 75
Pathway maturity • In addition, myelin sheaths covering the pathways continue to accumulate, gradually improving the precision and efficiency of normal communication—completed in the early 20s • Especially the large bundle connecting the two hemispheres with the limbic system—the corpus callosum • And the pathways connecting the prefrontal cortex with the limbic system
September 13, 1848 • The day that marked a watershed in our understanding of the human brain • An explosion at a railroad work site rocketed a 3’ 7” tamping iron through the head of Phineas Gage, severely injuring the prefrontal lobe of the brain • After the wound healed, he retained all of his mental faculties • However, his personality differed dramatically from what it had been • Formerly temperate, restrained and reliable, Gage became…
“fitful, irreverent, indulging at times in the grossest profanity, manifesting but little deference for his fellows, impatient of restraint or advice when in conflicts with his desires, at times pertinaceously obstinate, yet capricious and vacillating, devising many plans for future operation, which are no sooner arranged than they are abandoned.” –Dr. Gage’s physician
The teenage brain! Sounds just like…
Speaking of which…Dr. Walter Jackson Freeman (1895-1972) • $200 fee for lobotomies for “rambunctious” teenagers” in the early 1960s • Traveled the country visiting state mental hospitals in an RV dubbed the “lobotomobile” • Neurologist with NO surgical training performed 3,400 lobotomies
Another historical highlight…November 1, 1998 • Fred Gage, PhD. (Scripps Institute, La Jolla, CA) • Great, great grandson of Phineas Gage (the guy with the tamping rod) • Along with Gerd Kemperman (Karolinska Institute, Stockholm, Sweden) published the first proof that neurons could actually regenerate in the hippocampus—the gateway to memory and learning • HUGE finding in the world of Neurology • Defied the central and compelling dogma that neurons could not regenerate and, that you had all of your neurons at birth or shortly thereafter • WHY DIDN’T THIS MAKE THE HEADLINES???
Digression… • If we have the capacity to build new neurons, how can we help the process? • Say YES to meditation • Say YES to exercise • Say YES to antidepressants and other drugs
Say YES to drugs…antidepressants in particular… • Why does it take so long for antidepressants to work? • Why is this important to know???? • To help kids get through the first 3 to 6 weeks
Depression in children • Prozac is still the only drug approved by the FDA for the treatment of depression in children and adolescents • Prozac has a longer t½ life • Makes withdrawal more gradual • Keeps levels steady if a dose is missed (teenagers in particular often miss or skip doses) • How about a pet?
Psychotherapy… • A large government-financed trial recently found that Prozac worked better than talk therapy in helping teenagers overcome depression • That doesn’t mean that psychotherapy isn’t beneficial • Cognitive Behavioral Therapy—decrease negative thinking; anti-rumination strategies (most often when alone; call a friend; change what you’re doing)
Should you consider treating? • For every adolescent between ages 15-19, every 1% increase in the use of antidepressants corresponds to a drop in suicide rates (.23 per 100,000 per year) • Untreated depression increases the risk of severe depression in adulthood and the development of bipolar disease and personality disorders • 19% of high-school students have suicidal thoughts
The suicide controversy • Potential for suicide is highest in anyone being treated when their dosage is changing up or down • Suicide risk is highest in first 3-6 weeks of treatment—because the drugs AREN’T working yet!! • Antidepressants are associated with an increased risk of suicidal thoughts in about 1 in 50 who take it, but you can’t distinguish that one patient from the 8 or 9 in 50 depressed teenagers who would also be at risk of suicide because of underlying depression
Does depression run in families? • Nature or nurture? • Is there a gene? • Mirror neurons may play a major role in a child growing up with a depressed parent or caretaker • What are mirror neurons?
Mirror neurons (Allow us to understand othersactions and understand how others feel— “I feel your pain/your joy/your sorrow…”) • If you are raised in a household with depression does this increase your risk because of the mirror neuron theory? • Is depression contagious? • The area of joy in the frontal lobe is underdeveloped when children are raised by depressed caretakers
The “stress-related” theory of depression • The hormones of stress (cortisol and epinephrine) levels decrease serotonin levels and norepinephrine levels in the brain • High levels of cortisol KILL brain cells that produce serotonin • Chronic stress and depression may go hand in hand • Kids and stress today…have to get into the best schools, make the best grades, be the best at soccer, take the most advanced classes…whoa!
The Limbic system • The limbic areas (emotional areal) mature earlier than the prefrontal cortex; DISCONNECT BETWEEN THE TWO • This discrepancy between expressing feeling vs. thoughtful evaluation accounts for many of the teen behaviors that dismay parents and teachers… • “but he was such a sweet little boy…”
The Teenage Brain • “I just don’t understand what happened…”
“God’s way of making separation with children was to invent adolescence.” --Mark Patinkin
How many times a day does a parent say to their 16-year-old… • “What were you THINKING?” • Body piercing—51% and it’s not just earlobes
The tattoo craze… • Guys, out there, and everywhere…more aggressive with their tattoos… • Gals, are a bit more subtle…
The biggest MISCONCEPTION: Looking like an adult means they act like an adult… • Even though they may “look like adults” adolescents find it more difficult to:
Think before acting… • Interrupt an action under way—stop speeding, for example • Back to the prefontal lobe that underlies planning and voluntary behavior • The teenager freezes and screams (the limbic system--emotions) • The adult brakes hard and steers out of the way (the prefrontal cortex)
In real life, adolescents find it more difficult to: • Choose between safer and riskier alternatives • Difficulty resisting peer pressure • It’s that prefrontal cortex again—they’re using it somewhat, but it’s overtaxed…throw in peer pressure…”Aw c’mon, just once…” the stressful situation on an already taxed prefrontal lobe may give in to better judgment--
Leading to unprotected sex… • “It take many nail to build crib; only one screw to fill it.”
Adolescents find it more difficult to: • Resist peer pressure • Binge-drinking • And, drinking impairs judgment even further…
Digression: An interesting note on pre-natal programming… • In the womb…ETOH abuse by mom is the single most important variable for an adolescent to begin drinking • Add peer pressure during the teenage years and drinking can become a huge problem • Fetal alcohol syndrome remains the number one cause of mental retardation in the U.S. • IQ-68; where does that get you?
HPV as an STD leads to: • Cervical cancer • Penile cancer • Anal cancer • Vulvar cancer • Pharyngeal cancer • PUBLIC SERVICE ANNOUNCEMENT: • Consider the HPV vaccine! Gardasil