PSYC 4220 1st Edition Lect ure 10 Outline of Last Lecture I II Infant Reflexes Motor Development and Physical Growth A Dynamic Systems Theory Outline of Current Lecture I II III Physical Development Brain Development Enrichment of the Brain Current Lecture Physical Development Skeletal development Bones harden become dense Larger over early childhood Skull at birth soft made of several bones Fontanelles places were bones of skull meet soft spots By age 2 fill in with mineral deposits Body proportions change over childhood Infants are all head Head is 70 of adult size 1 4th of total body length By age 2 head 1 5th of body length By adulthood head only 18th of body length Brain Development Neuron proliferation neurons multiply very rapidly Happens from prenatal development till about 2 years of age up to 250 000 neurons being created per minute occurs during prenatal development 10 20 weeks gestation most rapid proliferation most neurons are formed by end of 6th month of gestation brain growth spurt 7th month gestation to 2 years old time when brain grows rapidly add more than half of brain s weight due to rapid production of Glia cells cells that support neurons myelination neurons coated with myelin which helps speed transmission isn t fully finished until early 20s migration movement of neurons to the proper locations where they belong movement of neurons to proper locations every neuron starts out with potential to become any type type depends on where it migrates to migration moves from innermost to outermost parts of the brain every neuron starts out with potential to become any type type depends on where it migrates to migration moves from innermost to outermost parts of brain synaptogenesis production of synapses start with few connections between neurons from birth 2 connections multiply rapidly infant has 40 50 more neurons than adult needs synaptic pruning if neuron is not often stimulated it dies deprivation of experience has negative impact on brain chimps raised in darkness raised infant chimpanzee in darkness for varying amounts of time the visual areas of the brain like the optic nerve ad retina were not able to develop in the way that they typically do because of lack of stimulation result functionally blind because synaptic connections were never made you need stimulation in order to develop the ability to see certain things Enrichment of Brain can have positive impact rats in enriched environment cortex heavier increased chemical activity plasticity degree to which developing structure behavior is modifiable due to experience neural plasticity greatest during first several years of life
View Full Document
Unlocking...