Nature Versus Nurture

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Nature Versus Nurture
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Todays Topics

• The Concept of Nature Versus Nurture
• Nature and Nurture in the Nervous System
• Developmental Milestones

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The Concept of Nature Versus Nurture
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What is Nature Versus Nurture?

• What determines our physical characteristics?

• Heredity?

• Nature

• Environment?

• Nurture

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What is Nature Versus Nurture?

• What determines our behavioral characteristics?

• Heredity?

• Nature

• Environment?

• Nurture

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First Discourse About Nature and Nurture

• Sir Francis Galton

• English Men of Science Their Nature
• and Nurture- 1857

• Discussed influence of inheritance
• and personal experiences

• No knowledge of genes

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Galton

• Coined term eugenics
• First to study twins

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1. www.ars.usda.gov/is/graphics/photos/k4323-18.ht
m
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Nature and Nurture in the Nervous System
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Nature and Nurture in the Nervous System

• The neuron and its synapses are important in
  nature and nurture

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1. http//chemistry.caltech.edu/fucose/Neural20C
oonections.htm
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Nature and Nurture in the Nervous System

• The neuron and its synapses are important in
  nature and nurture

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2
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1. http//biology.plosjournals.org/perlserv/?reque
stget-documentdoi10.1371/ journal.pbio.0040029
2. http//upload.wikimedia.org/wikipedia/en/1/15/P
urkinjeCell.jpg
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Genetics

• Heredity establishes tendencies

• Basic circuitry

• Behavioral traits

• Diseases

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Twin Studies
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• Maternal twins
• (identical)
• Fraternal twins
• (non-identical)

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1. http//www.mirrorkbranch.com/twins.html
2. http//www.twinsrealm.com/othrpics.htm
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Twin Studies

• MZ(C) DZ(C)
• Adult Disorders
• Schizophrenia .48 .17
• Affective illness .65 .14
• Alcoholism-Male .41 .22
• Alcoholism-Female .34 .31
• Criminal conviction .52 .23
• Panic disorder .24 .11
• Bulimia nervosa .23 .09

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Twin Studies

• MZ(C) DZ(C)
• Childhood disorders
• Attention deficit .58 .31
• Tourette syndrome .53 .08
• Autism .64 .09
• Juvenile delinquency .91 .73
• Reading disorder .68 .38

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Examples of Nurture
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• Sensitive Periods

• Use is critical

• Unused get pruned

• Baby with cataracts or strabismus

• Sexual orientation

1. http//www.bestnest.com/bestnest/RTProduct.asp?
SKUFEL-F-6
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Nurture

• Sensitivity

• Different than sensitive periods

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• Fetal alcohol syndrome

• Adult alcohol syndrome

1. http//www.google.com/search?qFetal20Alcohol
20Syndromesourceidmozilla2ieutf-8oeutf-8
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Nurture

• Plasticity
• Individuals who sign
• Learning
• Music and the brain
• Recovery of function

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Developmental Milestones in the Nervous System
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First Trimester

• Week 2- Neurons begin to differentiate
• Week 5- Synapses begin to form
• Most sensitive period to adverse environmental
  influences

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Second Trimester

• Week 18- Fetus can move

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18 Weeks
1. http//www.nlm.nih.gov/medlineplus/ency/images/
ency/fullsize/9575.jpg
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Third Trimester

• Sensory paths form

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1. http//www.google.com/search?qFetussourceidm
ozilla2ieutf-8oeutf-8
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Newborn to 3 Months

• Visual and other systems start to mature
• http//www.pbs.org/wnet/brain/episode1/infantvisio
  n/flash.html

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During First Two Years

• 100 billion nerve cells
• Myelination begins
• Motor systems begin to mature
• Language begins to develop

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During First Two Years

• Emotional systems begin to develop
• ?Memory systems develop
• ?Sense of self develops

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Two Years to 12 years

• Trillions of synapses have developed
• Sculpted by experience
• Strengthened by experience

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Teen Years

• A second growth and sculpting spurt
• Focused on the prefrontal region
• Involved in judgment and planning
• Teens are impulsive prior to the maturation of
  the frontal lobes

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Teen Years

• The brain continues to develop and synapses
  continue to form
• Myelination continues to occur
• Emotional systems and the brains attention
  system matures

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Early 20s

• ?Memory systems continue to mature
• ?Prefrontal cortex continues to mature
• Increasing ability to plan/exercise judgment
• Myelination continues

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Early 20s

• New synapses and processes added
• Language centers mature
• Perception centers mature

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2
1. http//neuro.psyc.memphis.edu/ugp/ugp-i-cortex3
.htm
2. http//en.wikipedia.org/wiki/ImageSynapseIllus
tration2.svg
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Up to 32 Years

• Myelination occurs up to 32

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Myelin
1. http//en.wikipedia.org/wiki/Myelin
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The Aging Brain

• Some small loss of cells and possibly some small
  decrease in the efficacy of synaptic transmission
• Plasticity present through out life

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Topics Covered

• The Concept of Nature Versus Nurture
• Nature and Nurture in the Nervous System
• Developmental Milestones