Current Trends in Understanding the Adolescent Brain

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Current Trends in Understanding the Adolescent
Brain

• Shirley Shen, Ph.D
• Clark County Juvenile Court

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Maturation of the teen brain
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Something more organized that looks like this..
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Like a remote control
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Cross section of brain
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Neuron
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Stages of brain development

• The infant is born with an overproduction of
  neuron, much more than the adult brain.

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• Neural connections, however, are not established
  during birth.
• Experiences in the childs environment leads to
  either reinforcement (wiring) of the neural
  connections or elimination of the neural
  connection (pruning)

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NIMH Study

• Dr. Jay GieddNational Institute of Mental Health
• Began studying the brain of normal children and
  teenagers every two years with a fMRI

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Implications of Dr. Giedds findings of the
adolescent brain

• Dr. Giedd found that prior to adolescence, there
  is a thickening in the grey areas of the frontal
  lobe.
• There are also profound changes in the amygdala
  and also in the nucleus accumbens

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Frontal Grey Matter Development in the Adolescent
Brain
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Frontal Lobe
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Function of Frontal Lobe

• Responsible for
• Executive functioning tasks such as
• planning
• strategizing
• organizing
• Attention functioning
• maintaining attention
• shifting attention

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Examples of Functional Impairments in Frontal
Lobe Lesions

• Short term memory is impaired with easy
  distraction.
• Impairments in divergent thinking (when there are
  multiple correct answers).

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Examples of Functional Impairments in Frontal
Lobe Lesions

• Impaired strategy formation and planning,
  especially in unfamiliar situations.
• There is inappropriate behavior with difficulty
  using social cues and information to direct,
  control, or change personal behavior.
• Inhibition impaired.

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• The frontal lobe functions as the CEO. The
  adolescent is just learning how to use the
  prefrontal cortex.
• However, it is not always very successful at it.
  

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When the frontal lobe is vulnerable

• When emotions are called on first to solve a
  problem
• During times of peer influence.

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What is the anatomical reason for this

• The brain is being reorganized during adolescene
• The more primitive portions of the brain, such as
  the sensorimotor region and the emotional regions
  are already developed

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Beatrice Luna-University of Pittsburg

• Adolescent risk taking
• Design- Asked both adults and adolescent to not
  look at a light placed in a brain scanner.

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Findings of Study

• Adults
• Able to not look at the light
• Used several parts of brain to manage the task

• Teens
• Able to not look at the light
• Solely used the frontal lobe to complete this task

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MRI Study by Dr. Yurgelun-Todd

• N19
• Suggestive that the prefrontal cortex attenuates
  or monitors what happens in the amygdala

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Implications

• Teens can use their frontal lobe.
• However, as they are learning to use it, they are
  using it even to do very easy tasks
• Teens are not good managers of their frontal
  lobe.
• It is as if the manager makes himself take on the
  role of all his employees.

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Amygdala
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Function of the Amygdala

• Emotional center of the brain
• It has been suggested that the amygdala functions
  to associate sensation with reward or punishment.
  
• The amygdala does seem to be closely associated
  with the feeling of fear

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Amygdala and the Adolescent Brain

• Adolescents tend to use their Limbic System more
  often in the decision making process, since their
  Frontal Lobes are not fully developed.
• The Amygdala, part of the Limbic System, is
  responsible for impulse reactions, emotional
  reactions, fear, and is also used in the
  decision-making process of adolescents.

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Implications of Amygdala on Adolescent Behaviors

• Results in adolescents making more decisions
  based on emotional reactions rather than
  reasoning.
• Less capable ability to weigh long term
  consequences.
• Developing adolescents tend to use their Amygdala
  when responding to other peoples emotions,
  yielding more reactionary, less reasoned
  perceptions of situations than adults.

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• Teen brain Adult brain

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Nucleus Accumbens
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Mortality Rates in Adolescents in the U.S.
1979-1988

• Approximately three fourths of the more than
  40,000 deaths each year among persons aged 10-24
  years in the United States are related to
  preventable causes
• motor-vehicle crashes (37),
• homicide (14),
• suicide (12), and
• other injuries (e.g., drowning, poisoning, and
  burns) (12).

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Function of Nucleus Accumbens

• Directs motivation
• Responsible for how much effort an organism will
  expend in order to seek reward
• Also often referred to as the brains reward
  system
• Has significant implications in the reward system
  for drugs in the brain

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Studies of adolescent response in risk
taking-Wheel of fortune task
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• Adolescents took significantly more risks than
  did adults and were
• Adolescents were happier when they won money, but
  were less upset than adults when they lost.
• In response to feedback, adolescents activated
  the nucleus accumbens more than did adults, while
  adults engaged the amygdala and PFC more than did
  adolescents.

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Teens Perception of Self

• Also a function of brain development

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Who Am I ?????

• Who I am depends on who my friends think I am.

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My Friends tell me who I am socially
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Social Influences
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Who Am I ?????

• Who I am depends on who my parents think I am

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My parents tell me who I am academically
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Dr. Jennifer Pfeifer-University of Oregon
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• Two separate types of questions were asked while
  subjects were put in an fMRI scan.
• What do I think of myself(direct self
  apprasial)
• What others think of me..(reflected self
  apprasial)

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Study Findings

• When asked what others thought of you, both teens
  and adults used the medial prefrontal cortex and
  also the temporal parietal areas of the brain.

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However

• When asked how adults and teens think of
  themselves, teens continued to use the same
  region of the brain, suggesting that teens self
  appraisal is tied into what they believe others
  think of them.

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Studies on brain vulnerability to drugs and
alcohol as it relates to risk taking

• Susan Anderson-Harvard Medical School
• Placed juvenile and adult rats in situation where
  they were able to have access to cocaine.
• Young and old rats opted not to be in that
  environment, but adolescent rats tended to be
  immensely attracted to the situation.

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• Scott Swartzwelder-Duke University
• 7 million youngsters binge drink once a month
• Effects of alcohol has lasting impact on the
  adolescent brain, particularly in the area of
  the hippocampus which is responsible for memory.
• Teen brains do not recover as quickly after
  drinking as adults-demonstrated in memory tests
  3-weeks post last binge episode.

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• While their brains are much more vulnerable to
  alcohol, it has less sedating effects. Teens
  dont get tired after drinking the same way that
  adults do.
• Teens are also less vulnerable to balance
  problems and hangovers from drinking

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Alcohols affect on the hippocampus
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• Receptors are activated by the neurotransmitter
  glutamate and allow calcium to enter neurons,
  setting off a cascade of changes that strengthen
  synapses, by helping to create repeated
  connections between cells, aiding in the
  efficient formation of new memories.

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• But at the equivalent of one or two alcoholic
  drinks, the receptors' activity slowed, and at
  higher doses, they shut down almost entirely.

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What Do We Know

• Drinking during the teen years significantly
  increases a youngsters chances of becoming
  alcoholic in adult life.
• Drinking, even moderately in teen years
  significantly damage the hippocampus.
• The long term damage of drinking in adolescence
  is significantly more than in the adult.
• These damages are long term

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How brain research affects legal ruling for
adolescents
Jackson v. Hobbs
mandatory life-without-parole sentences for all
children 17 or younger convicted of homicide are
unconstitutional
Mandatory life without parole for a juvenile
precludes consideration of his chronological age
and its hallmark features among them,
immaturity, impetuosity, and failure to
appreciate risks and consequences, Justice Kagan
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• Relationship
• Relationship
• Relationship

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• Have concrete specific goals and tools that will
  work for one or two days.
• Dont make goals so long that it is not salient
• Make sure that kids are appropriately diagnosed.
• Most youths in detention have contributing
  academic, learning, mental health or a
  combination of all of them

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• Make doing well more exciting than the crime.
• Encourage exercise-exercise increased plasticity
  to brain development.
• With increased opportunities, the brain will
  learn to do it better and quicker.

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References

• 1 Giedd JN, Blumenthal J, Jeffries NO, et al.
  Brain development during childhood and
  adolescence a longitudinal MRI study. Nature
  Neuroscience, 1999 2(10) 861-3.
• 2 Rapoport JL, Giedd JN, Blumenthal J, et al.
  Progressive cortical change during adolescence in
  childhood-onset schizophrenia. A longitudinal
  magnetic resonance imaging study. Archives of
  General Psychiatry, 1999 56(7) 649-54.
• 3 Thompson PM, Giedd JN, Woods RP, et al. Growth
  patterns in the developing brain detected by
  using continuum mechanical tensor maps. Nature,
  2000 404(6774) 190-3.

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• 4 Sowell ER, Thompson PM, Holmes CJ, et al. In
  vivo evidence for post-adolescent brain
  maturation in frontal and striatal regions.
  Nature Neuroscience, 1999 2(10) 859-61.
• 5 Baird AA, Gruber SA, Fein DA, et al. Functional
  magnetic resonance imaging of facial affect
  recognition in children and adolescents. Journal
  of the American Academy of Child and Adolescent
  Psychiatry, 1999 38(2) 195-9.