infant, child and adolescent brain Flashcards
where do the amazing capabilities of the human brain arise from
- stoundinly intricate communication among billions of interacting cells.
schizophrenia
may occur because pathways in the brain and connections to it formed incorrectly in early life
susceptibility to autism spectrum disordes
- genes that infleunce brain development could play a role in this
baby’s brain three trimesters after development in the womb
- after birth, baby’s brain continues to grow and develop
- avg weight of a newborn human baby is about 370 grams, slightly less than a pound
average weight of an adult brain
3 pounds with about 86 billion neurons
newborn baby brain
- product of 40 weeks of brain development
- rapid development conitunes after birth
growth rate after birth
- immediately after birthm the growth rate of the whole brain is about 1 percent per day
- rate slows as baby ages
reaches about 0.4 percent per day by three months after birth
baby at 90 days old
- overall brain volume is 64 percent larger than at birth
fastest growing brain region of the brain at 90 days old
- cerebelllum
- it is more than double its volume at birth
- cerebellum has the most neruons
- helps with learning mtor skills and movements
- important for babies learning to grab thing and eat good
what is the overall increase in brain volume the result of
- a large number of brain cells growing, multiplying (proliferating), maturing (differentiating) and migrating
neruon increase during the first three months of life
- the number of neruons in the cortex increases 23-30 percent,
- dendrites and axons of these neruons grow longer, make many connections (sunaptogensis), making the brain bigger
what is another way the brain grows in volume
- cells known as glia grow, multiply, and provide myelination (by oligodendrocytes)
- brain’s white matter looks white because of all the myelin-wrapped nerve fibers
five years after birth
- child has reached about 90 percent of its adult size
- leaves plenty of room to grow during childhood, adolescence, and early adulthood
two year old’s brain
- number of connections between nerunons (synaptic densirt) increases rapidly
- has 50 percent more synspases than an adult brain
- still only about 80 percent the size of an adult brain
- too many synapses for the brain to maintain
when does synaptic pruning occur
- occurs at around two years old, during the first couple of years after birth
- there are too many synapses for the brain to maintain
- synapses use energy and resources
- brain must reduce the number and fine-tune these connections through synaptic pruning
- it is shaped by the toddler’s experiences as they grow
synpatic pruning
- allows weaker connections to diminsh while stronger synpases that are activated more often will grow and stabilize
humans are born with more developed brains than other animals
FALSE
- compared to other animals, humans are actually born wit less developed brains
- human brains also take longer to mature
e. .g. squirrel monkeys reach their adult brain size at 6 months old
do humans develop more in the womb orout>?
- human brains grow and develop extensively after birth
- developing brains are more easily shaped by environment and experience
- this is an advantage because It helps us adapt appropriately to thee surrounding environment.
criticial periods
- inputs from sensory, motor, and even emotional aspects of life experiences affect how the brain develops and adapts to a given environment.
what factors exert a great amount of influence during critical periods
- genes and environemnt exert strong influences
- they form nerual circuits that affect learning and behaviour
what does shaping of connections involve
- neruonal cell death
- synpatic pruning
- these processes occur in the embryo and in early postnatal life
changes in nerual connections
- cahnges during the critical periods they coincide with higher rates of learning - e.g. a toddler learning to run or to speak multiple languages
teenage brain
- many changes
- amazing capacity to learn
- more synaptic pruning
- stronger connections beat out weaker ones in a process called competitive elimination
- brain is improving its connections
what happens to neurons in the teenage brain
- improving connections :
- neruons extending their dendritic branches
- myelination of axons increases (esp in frontal lobes)
longitudinal studies
- ## esp important bc they reveal how early life events and environment can affect outcomes later in life e.g. education, or risk for disease
second cirtical period
- adolescence
- more complex functions of the brain develop and can be infleucned by the environment and experience
adolescent brain from an MRI
- ## shows an increase in white matter volume (esp in corpus calosucm)
what does the growth of the corpus c. indicate
- enhanced learning capacity in adolescenes due to increasing connections
what contributes to teenager’s risky behavirours.. increased risk-taking, and sensation seeking, and aspects of enhanced learning ability,
- enhanced connetions
- changes in the brain’s reward systems
changes in the balance between frontal and limbic systems
-
frequent drug use
- associated iwth damage to brain regions important for cognitive functions such as memory, attentions and executive functioning
white matter and addiction
- DTI shows that alacohol and drug abuse can cause significant changes in gray and white matter in adolescents
- adolescents who did that studd had reduced gray matter volume and reduced white matter integrity
binge-drinking during adolescnece
- lower brain activity
- les sustained attention
- poorer performance on a working memory task
when do human brains develop until
- until thirty years old
- different brain regions show diff rates of growth and maturation
