Lecture 35 Outline of Last Lecture I. Implicit memories do not require conscious recollection, whereas explicit memories doa. Consolidation involves storing a short-term memory into a long-term oneb. Reconsolidation diminishes the accuracy of memoriesII. Emotional memories are influenced by the amygdalaIII. Spatial memories are influenced by the hippocampusIV. Forming memories involves numerous neural mechanismsa. Neurogenesisb. Synaptogenesisc. Increase in the number of AMPA receptorsd. Increase in the size of a receptive membraneOutline of Current Lecture I. BDNFs (brain development neurotrophic factors) are necessary for proper developmentII. Zygote formation embryo stage fetal stageIII. Experiences, genes, hormones, and brain injuries all influence the development of neural circuitsIV. Neural plate pinches in and forms a neural tube that becomes the central nervous systema. It is lined with neural stem cells that may differentiate into neuroblasts or glioblasts, then further into specific types b. Some remain in adults in the subventricular zoneV. Differentiated cells differ by changes induced through epigenetic alterationsa. Methylationb. Neurotrophic factorsCurrent Lecture- Brain development neurotrophic factorso Exist in the hippocampus, resulting in neuronal death- Three perspectives on brain developmento Planning skills can be measured by the Tower of Hanoi (match the goal in as few moves as possible)o Brain development can be used to predict behavior development and vice versa What neural circuits must be emerging?o How certain experiences, genes, hormones, brain injuries impact brain development- Neurobiology of developmento Common body plans among related species in embryos Nutrients promote the activation of BDNF genesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. NSCI 110 1st Editiono Zygote formation occurs at fertilization and lasts about 2 weekso Between 2-8 weeks embryo stageo Between 9 weeks – birth in humans fetal stage- Neural plate: thickened region of the ectoderm (outermost) cell layero Neural groove is enclosedo Ultimately becomes the neural tube that will become the CNS Small space inside becomes the ventricular system, and spinal cord central canalo Forebrain, midbrain, and hindbrain are visible as a human embryo at about 28 days Prosencephalon, mesencephalon, rhombencephalon- Anterior end of the neural tube forms the brain and the posterior forms the spinal cordo Neural tube defect occurs when the tube fails to close entirely Low folic acid levels may result in a higher risk of neural tube defects Spina bifida o At around two months sexual differentiation occurs (sexual dimorphism) Genitals and brain regions sex steroids influence how genes are expressed 3 months looks human 7 months gyri and sulci begin to form 9 months brain similar to an adult brain- The neural tube is the “nursery” for the CNS it is lined with neural stem cellso In adults, some stem cells remain in the subventricular zone that lines the ventricleso They divide to produce two cells: one lives to divide again, one is a progenitor cell that divides to produce neuroblasts and glioblasts Further differentiate into specific cell types How do these cells differ? Epigenetic changes- Epigenetic changes drive cell differentiation o DNA methylation methyl group attaches to a cytosine on DNA sequenceo Histone modifications allow different rates of transcription Additions to histone tails causes looser or tighter conformationso Very sensitive to environmental factors- Chemical signals cause a specific subset of genes to be expressedo Specific proteins are produced and specific cells are “differentiated”- Neurotrophic factors are chemical signals such as epidermal growth factor and basic fibroblast growth factoro Stem cell + EGF = progenitor cell- Shortly after neurogenesis begins neuroblasts differentiateo Neural migration: how do cells know where to
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