Injury and Brain Development
Class Starter Questions
(journal entry #10 p.230- 234)
1. Will a child with brain damage recover?
2. When is the worst and best time for brain
injury?
3. Can the use of prescription drugs by a
pregnant woman have an impact on the
development of her baby’s brain?
4. What is spina bifida and anencephaly?
5. What are the causes of Developmental
Disability?
6. How Do Any of Us Develop a Normal Brain?
Will a child with brain damage recover?
‘children with major birth-related injuries to the
frontal lobes of their brain have severe and
permanent behavioral abnormalities in
adulthood’
Donald Hebb (1930’s)
When is the worst and best
time for brain injury?
Damage on Day 1
(8th month in fetal development)
Neurons have simple
dendrites and fewer
spines than normal
adults
Behaviorally, these rats
are cognitively retarded.
Damage on Day 10
(6 months- 2 yrs for a human)
Neurons have expanded
dendritic fields and
denser spines than
normal adults
Behaviorally, these rats
show a recovery in
function.
When is the worst and best
time for brain injury?
• Worst time for brain injury:
– Last half of intrauterine period and the first
few months after birth
• “Better” time for brain injury:
– First few years after birth
Drugs and Brain Development
Can the use of prescription drugs
by a pregnant woman have an
impact on the development of her
baby’s brain?
Yes! Even low doses of antidepressants
appear to alter prenatal neuron
development in the prefrontal cortex
Drugs and Brain Development
• Precise effects of drugs on prenatal brain
development are poorly understood
• There is some evidence that:
– Prenatal exposure to psychoactive drugs may
increase the chance of later drug use
– Prenatal exposure to drugs such as nicotine and
caffeine increase the chance of learning
disabilities and hyperactivity
Other Kinds of Abnormal Brain
Development
Genetic Abnormalities
• Spina bifida
– Spinal cord abnormality due to the failure
of the neural tube to close completely
– Associated with serious motor problems
Spina Bifida
Anencephaly
– Front end of the
neural tube does
not close
– Failure of the
forebrain to
develop
– Infants typically die
soon after birth
Abnormal Brain Development
Does abnormal brain development
always result in behavioral
abnormalities during childhood?
No! Sometimes behavioral effects may only emerge as the
maturing regions begin to play a greater role in behavior.
Example: frontal lobe injuries
(frontal lobes continue to develop until early adulthood)
What are the causes of
Developmental Disability?
– Genetic abnormalities
• Down syndrome
– Prenatal exposure toxins such as alcohol
• fetal alcohol syndrome
– Birth trauma, such as anoxia (oxygen
deprivation)
• cerebral palsy
– Malnutrition
• Kwarshiorkor
– Environmental abnormality, such as sensory
deprivation
• Romanian orphans
How Do Any of Us Develop a Normal
Brain?
• The brain has the capacity to correct minor
abnormalities that may occur during
development (brain plasticity).
• The plastic properties of the brain continue
into adulthood and allow us to cope with the
neuronal loss that occurs during aging.
Review: Brain Development and the
Environment
• The brain is especially plastic during its development
and can therefore be molded by experience into
different forms.
• The structure of the brain changes in response internal
events (hormones), injury, abnormal genes and drugs.
• At critical periods in development, specific parts of the
brain are particularly sensitive to experience and the
environment.
• If experiences are abnormal, then the brain’s
development is abnormal.