Lifespan cognitive and brain development normaitve patterns
lifespan development
neural mechanisms
Lifespan cognitive and brain development individual differences
environmental differences
mental health
ltm brain development
Hippocampal formation
parahippocampal cortex
perirhinal cortex
entorhinal cortex
Learning of regularities brain development
midbrain modulation
ventral tegmental area
substantia nigra
corpus striatum
feedforward and feedback processing brain development
frontal lobe
parietal lobe
occipital lobe
Principles of brain development
over protracted period of time
complex interaction
molecular, cellular & environmental elements and systems
progressive -> structures/systems that emerge set the stage for development of subsequent systems
key concepts
neural plasticity
progressive differentiation and commitment
sources of developmental constraint
Neural plasticity
adaptive
adjusting to biological & environmental contingencies on all levels
evident in young organisms but continuous until adulthood
Example: face processing
Progressive differentiation
gradual elaboration of neural systems
distinct cell types
patterns of connections
different functions within neural network
Periods of prenatal development
Period of
ovum 2 weeks -> week 1 germinal -> conception & zygote implanted in uterine wall
embryo 8 weeks
fetus 36 weeks
embryonic development
cell division
migration
differentiation -> embryonic stem cells are no longer equivalent and interchangeable
cell death
fetal development
growth of physical structures & body
common site of birth defect
week 3
heart & ZNS
weeks 4 & 5
heart, arm, leg eye
weeks 6
teeth, ear
week 7-8
brain, ear, palate
week 8
external genitalia bis 12
week 20-36: brain
progressive commitment
stabilization of neural elements and systems
experience-expectant plasticity
plasticity decline when neural elements become commited to particular systems
sources of developmental constraints
genetics
environment
time
Gene functions
pleiotropy
polygenic
no prescription of developmental processes but:
availability & quantity at right time constrains development
genes can have multiple phenotypic effect
multiple genes for one phenotype
development = adaptation to contingencies of environment
no normal development when no typical environmental input
experience-expectant plasticity —> without expected input no normal development
experience-dependent plasticity
Experience-dependent plasticity:
environment effects on brain within normal range
brain development is temporally constrained
failure at earlier steps —> catastophic failure of brain development
critical / sensitive periods —> when system is particularly plastic for certain type of experience
number of neurons
no change with develppment
volume quadruples but increases in
fiber bundles
dendrites
myelinization
formation of neurons & migration almost entirely prenatal
exception: adult neurogenesis in hippocampus and olfactory bulb
increases in interconnections among neurons with age
increased
size and complexity of dendritic tree
density of synaptic contacts between cells
increased number of synapses & synaptic pruning
steady increase in synaptic density in human cerebral cortex
age dependent when peak density is reached
sensory areas earlier than prefrontal
synaptic pruning -> synaptic loss after initial overproduction
white matter increases
more myelinated with development
neuronal signal transmission is sped up
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