CAP102709 - -the axon regenerates-never learns to...

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October 27, 2009 Frog eye; vision Superior colliculus Homologous: same evolutionary origin, but may or may not have same function Analogous: not the same origin, but have same function Superior Colliculus: Optic tectum in frogs is analogous to visual cortex in mammals Optic tectum: structures are completely crossed from eyes to optic tectum What happens to regenerating axons in adult frogs or fish? Nogo gene- inhibits axonal regrowth in mammals, birds -Roger Sperry: severed optic nerves, noted that axons regenerate -found (in frogs) that ventral in the retina, lead to damage in the contralateral in the optic tectum -specificity, how it comes about. -take one eye, rotate 180 degrees -put flies in front of fly, frog’s tongue goes opp (180 off)
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Unformatted text preview: -the axon regenerates-never learns to adjust--but! In humans, first will go opposite, but then will be able to alter the usage of visual systems Sperry thought that:-nasal chemical, dorsal chemical (directions) Gaze, Keating, Yoon, Jacobson-developed diff techniques of testing; ex: take 2 eyes, split each eye in 2 in vertical direction or horiz direction-switched around, wanted to see optic tectum wiring-1 st synapses being made, recorded one pattern, but then after 90 days, recorded another pattern short specification time (frogs) fish:-eye grows concentrically; tectum grows eccentrically (like a seashell)...
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