[Verse 1] Light bounces off the world into your waiting eyes Through the pupil, hits the lens, gets flipped and twisted twice What was left becomes the right, what was right becomes the left The retina receives this topsy-turvy theft Nasal side and temporal side, each with different fates One will cross, one will stay, as the visual pathway waits [Chorus] At the chiasm crossing, where the optic highways meet Nasal fibers jump the line, temporal fibers keep their beat Left brain sees the right side world, right brain takes the left Contralateral visual fields, perfectly bereft From both eyes to one hemisphere, the crossing rule's complete Binocular combination makes the neural circuit sweet [Verse 2] Picture standing in a field, mountains on your right Your left eye's temporal side captures that majestic sight But your right eye's nasal half sees those same peaks so tall Both send signals to left brain, answering the call The lens has done its flipping trick, nasal sees what's far away Temporal captures close-up views in this neural ballet [Chorus] At the chiasm crossing, where the optic highways meet Nasal fibers jump the line, temporal fibers keep their beat Left brain sees the right side world, right brain takes the left Contralateral visual fields, perfectly bereft From both eyes to one hemisphere, the crossing rule's complete Binocular combination makes the neural circuit sweet [Bridge] Stereopsis needs this plan, depth perception's clever scheme Corresponding retinal points merge into one stream Same hemisphere processing, same cortical column too Two eyes become a single view, dimensional and true The crossing rule delivers what binocular sight demands United visual processing from evolution's hands [Verse 3] Remember this decussation, half cross and half remain Nasal axons switch their sides, temporal stay in lane Each hemisphere receives the whole contralateral scene From both your eyes combined as one, sharp and crystal clean The chiasm sorts the traffic with this ancient neural code Splitting visual information down the proper road [Chorus] At the chiasm crossing, where the optic highways meet Nasal fibers jump the line, temporal fibers keep their beat Left brain sees the right side world, right brain takes the left Contralateral visual fields, perfectly bereft From both eyes to one hemisphere, the crossing rule's complete Binocular combination makes the neural circuit sweet [Outro] So when you see the world around, remember how it flows Crossed and sorted, mixed and matched, as visual data goes The decussation rule ensures your hemispheres align Processing the world you see in patterns so divine
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