Juraska 735 Psychology office hour Wednesdays 11 15 12 30 jjuraska illinois edu You have to come to class Nervous system development zygote undifferentiated development specification genes layer formation outer layer ectoderm occurs 14 18 days after fertilization The Neural Tube Figure 8 5 Formation of the Neural Tube Kolb Whishaw Introduction to Brain Behavior Fourth Edition Copyright 2013 by Worth Publishers The Neural Crest Neural tube Central Nervous System Neural crest Peripheral Nervous System Stages of neural development 1 proliferation 2 migration neuroblasts 3 Differentiation dendrites axons synapses becomes a neuron growing axon CAM cell adhesion molecules target neurotrophic factors NGF nerve growth factor BDNF brain derived neurotrophic factor 4 Pruning and cell death apoptosis genetic program too little neurotrophic factor This stage overlaps with 3 differentiation Right eye closed Growth of axons and pruning both occurred 5 myelination Oligodendroglia CNS PNS Timing Early spinal cord reflexes Late Proliferation 1 Cerebellum 2 years 2 Olfactory bulb life 3 Dentate gyrus of hippocampus life Differentiation 4 Cerebral cortex visual to prefrontal Brain weight birth to 12 years 3 5x 12 years adulthood Dendritic Growth Figure 8 13 Neuronal Maturation in Cortical Language Areas Kolb Whishaw Introduction to Brain Behavior Fourth Edition Copyright 2013 by Worth Publishers Synaptic strengthening and competition Left eye Right eye Kalat 2004 Synapses that are used together are strengthened together Wiring of visual cortex use both eyes binocular neurons Enriched condition individual condition EC IC Juvenile through adolescence better at mazes and more dendrites and synapses Lenroot Giedd 2006 Development of the cerebral cortex No proliferation after birth Dendritic growth new synapses pruning Visual cortex first year Prefrontal cortex through adolescence Human MRI gray matter cell bodies white matter axons Lenroot Giedd 2006 Adolescence to adulthood rats loss of neurons between puberty and adulthood in medial prefrontal cortex and in amygdala both rats and humans synapses are lost in prefrontal cortex myelination increases adult humans through the 4th decade adult brain changes proliferation in 2 brain areas only no long axon growth grow and prune dendrites increase glia add and subtract synapses