PSYC 307 1st Edition Lecture 4 Overview of Previous Lecture I Biological Backgrounds Overview of Current Lecture II Brain Development a Neurons b Brain Maturation c Experience Expectant Plasticity d Experience Dependent Plasticity e Studying Brain Functions III Prenatal Development a Periods of Prenatal Development Current Lecture Sept 11 Brain Development I Neurons make up the brain a Made up of synapses that send signals between neurons and throughout the brain b Gray matter cell bodies and dendrites c White matter myelin sheaths neural axons II Brain Maturation development a Neurogenesis birth of cells in neural tube i Most nerve cells are born prenatally 1 Few are formed in adolescence or adulthood b Migration of cells cells move to their correct location i DNA tells them where in the brain to go ii Glial cells transport them there iii Brain build in an inside out pattern the newest cells are at the top of the brain oldest in the middle 1 Hippocampus only part of the brain not built that way iv Very organized layers columns of cells c Cell differentiation i Develop important parts once they are in their correct location 1 Post natal d Synaptogenesis connection between neurons e Myelination occurs in adolescence f Synaptic pruning pathways become efficient by cutting down on the number of synaptic pathways i Two years of age an individual has the most synapses they will ever have 1 Centered in the visual cortex low processing at this age ii Different parts of the brain mature at different rates 1 3 years peak of maturation in prefrontal cortex g parts of brain diagram III Experience Expectant Plasticity a Brain development as a result of ubiquitous experiences i Experiences common across all people cultures 1 Language cognition visual perception ii Sensitive periods of development 1 Specific time periods for development a Ie language b Ie binocular vision both eyes must work together to develop correctly iii Vulnerability of the brain IV Experience Dependent Plasticity a Neural connections are created and reorganized as a function of experience V Studying Brain Functins a EEG ERP fMRI etc Sept 11 Prenatal Development I Periods of prenatal development a Germination 0 2 weeks i Zygote sperm and egg come together one cell 1 Takes 36 hours for first cell division mitosis a 23 pairs 2 Twinning occurs at this stage monozygotic or dizygotic ii Blastocyst takes 1 week 1 Inner cells embryonic disk new organism 2 Outer cells trophoblast protective covering turns in to placenta iii Implantation end of the first week 1 Blastocyst implants in uterine lining b Embryonic Period 3 8 weeks i Major development of organs and systems ii 3 layers 1 Endoderm eventually forms digestive and respiratory systems 2 Mesoderm forms circulatory system bones muscle internal organs 3 Ectoderm forms nervous system sensory receptors skin iii Support systems develop 1 Placenta 2 Umbilical cord connects fetus to placenta so that it can receive nutrients 3 Amnion amniotic sac forms buffer of protection keeps skin moist iv Major changes 4 8 weeks 1 Rapid growth ears eyes jaw neck 2 Limb buds form arms legs fingers toes 3 Fetus begins to respond to touch c Fetal period 2 9 months i Most vital organs have already been formed ii Time of extreme growth development for the fetus 1 3rd month lungs begin to expand and contract sex can be determined by ultrasound not always accurate 2 2nd trimester 4 6 months a Mother can begin to feel the fetus moving i Lanugo and vernix protects the baby s skin b Sucking eyelashes eyebrows activity c Eyes opening 3 3rd trimester 7 9 months a Age of viability if a baby is born during this time it will need medical help and attention to live and grow i Baby outside the womb that should still be inside ii Create womb like environment so that they can continue to develop b Cerebral cortex enlarges c Fetus spends more time awake
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