Pnb 2xb3 - Neural Development Already Passed

Contact attractants/repellents {Ans: guidance molecules that attract or repel without concentration gradients - have to touch the molecule to be attracted/repelled (i.e. ephrins are contact repellents)}Ectoderm {Ans: brain and skin (outer layer)}Apoptosis {Ans: cell death; crucial part of brain development}Floorplate {Ans: the midline part of the neural tube (lines the neural tube)}Spontaneous retinal waves, before eye-opening {Ans: - in early postnatal life are caused by release of ACh from starburst amacrine cells - promote eye-specific activity in the LGN and cortex - cause retinal ganglion axons to have activity spread across the retina - activity can be propagated up to V1}Spinothalamic tract decussation {Ans: - slit is a chemorepellent for Robo1 and Robo2 receptors produced by growth cones - netrin is the chemoattractant - slit and netrin are produced by the floorplate/midline glial cells - netrin attracts axons to the midline, but once they decussate slit repels them from crossing back - before decussating, axons don't produce much Robo - but start to produce more after decussating}