PSY 201 Lecture Notes - Lecture 3: Myelin, Neural Tube, Prenatal Development
Document Summary
Neural plate: a flat structure a group of cells creates roughly 3 weeks after conception. At 4 weeks, the neural plate fold to form a tube that ultimately becomes the brain and spinal cord. When the ends of the tube fuse shut, neurons are produced in one small region of the neural tube. The brain is built in stages, beginning with the innermost layers and so on. In the 4th month of prenatal development, axons begin to acquire myelin. Neurons in the deepest layer are positioned first, followed by the second layer, Layering process continues until all 6 layers of mature brain are in place. This process continues through infancy and into childhood and into adolescence. Neurons in cortex are among the last. In months after birth the brain grows rapidly. Axons and dendrites grow longer and, like a maturing tree, dendrites quickly. Neurons that carry sensory info are the first to acquire myelin sprout new limbs.
