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The Brain & Plasticity
Growth & Development
Carolyn R. Fallahi, Ph. D.
5/24/2017
Dr. Carolyn R. Fallahi
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Growth & Development
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Physical Growth: rapid growth through first
year.
The pace of weight gain slows during the
second year, it still continues to increase.
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Disproportionate growth
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cephalocaudal principle: “head to tail”
Proximodistal principle: “near to far”
Principle of Hierarchical Integration: simple
skills typically develop separately and
independently. Later they are integrated into
more complex skills.
Principle of the independence of systems: The
body systems grow at different rates.
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Dr. Carolyn R. Fallahi
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Facts about the Brain:
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At birth, the brain has all the brain cells or neurons
that it will ever have.
Brain neurons do not regenerate.
The environment modifies brain structure.
Neural plasticity – ability to change its structure and
function in response to external experiences.
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Dr. Carolyn R. Fallahi
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Brain Research
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At birth, humans do not yet possess a fully
operational brain.
Environment affects how genes work; genes
determine how the environment is interpreted.
Dr. Marion Diamond at the U. of CaliforniaBerkley, 1960s.
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More Facts about Brain
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The brain develops in an integrated fashion
over time.
Learning is gradual. For ex…a baby doesn’t
learn how to talk in one week.
The brain is curious and seeks connections
between the new and the known.
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More Facts about Brain
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IQ is not fixed at birth.
Intervention programs can prevent children from
having low IQs.
Some abilities are acquired more easily during
certain sensitive periods.
PET scans – Positron Emission Tomography.
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Applications of Brain Research
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Premature Infants
For example….
Maternal smoking
Alcohol use
Infant malnutrition
Lead poisoning
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Dr. Carolyn R. Fallahi
Policies
We spend 7x more on
care for elderly than on
children from birth to 5
years old.
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Brain Research
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The role of nutrition of brain function.
How brain chemicals affect mood,
personality, and behavior.
The connection between mind/brain and the
body.
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Dr. Carolyn R. Fallahi
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The developing brain
B – 3 Years
At Birth:
 100 billion neurons
 1 trillion glial cells –
honeycomb that protects &
nourishes the neurons
 Lay out circuits in place.
 Sensory experiences
change brain structure.
5/24/2017
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Dr. Carolyn R. Fallahi
Deprivation of
stimulating
environment leads to
decreased brain
development.
Malleable brain, e.g.
stroke, epilepsy
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Genes and the Brain
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100,000 genes in
human DNA
Some 50,000 genes
appear to be dedicated
to constructing and
maintaining the
nervous system.
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Dr. Carolyn R. Fallahi
Experience kicks in.
The connections lends
the growing brain
exceptional flexibility
& resilience.
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Brandi Binder
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Neural circuitry & stress
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Children who are physically abused – brains
tuned to danger.
Emotional deprivation – marked reduced
activity in the left frontal lobe.
Physical, emotional abuse / neglect – child’s
brain is forgiving – for a time.
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Dr. Carolyn R. Fallahi
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Emotional deprivation early in life
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Brain wave patterns of brain activity
displayed by children who were born to
mothers diagnosed as suffering from
depression.
As infants, these children showed markedly
reduced activity in the left frontal lobe – an
area of the brain that serves as a center for joy
and lighthearted emotions.
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Dr. Carolyn R. Fallahi
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Eye
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Children born with a cataract will become
permanently blind in that eye if the clouded
lens is not promptly removed. Why? The
brain’s visual centers require sensory stimulus
to maintain their tentative connections.
Critical period for the eye is 3 years old.
Same holds true for hearing.
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Dr. Carolyn R. Fallahi
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Language
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Many linguists believe that language skills
unfold according to a strict, biologically
defined timetable.
The case of Genie.
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Plasticity
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Brains greatest growth spurt decreases at about 10
years old.
By 18, the brain declines in plasticity but increases
in power.
Potential for greatness is encoded in the genes; but
whether potential is realized involves how patterns
are etched by experience in critical years.
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Dr. Carolyn R. Fallahi
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Politics of Biology
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Addictive disorders, sexual orientation, criminality?
Due to nature/nurture.
Research: finding a new gene for lots of things.
E.G., shyness, tendency to divorce, lack of
happiness, etc.
Implications for belief in genes: decreases sense of
responsibility for ailments. E.G., alcoholism –
victim or have control?
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Dr. Carolyn R. Fallahi
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Politics of Biology
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Research for years…to identify genetic roots for
aggression, violence, criminality.
1965 study found imprisoned criminals were more
likely than other people to have extra Y
chromosome.
Research did not turn out to be accurate. XYY men
were less intelligent but not aggressive.
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Genetics & Psychiatric Disorders
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Schizophrenia – past view…resulting from mothers
who were apathetic toward their children. New
view: genetics.
Takes guilt away.
Managed care issues – if due to biology – will only
pay for drug therapy.
Homosexuality studies. LeVay (1991).
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Dr. Carolyn R. Fallahi
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