[Verse 1] Back in eighty-two, two scientists had a hunch Studied monkey brains with surgical precision's punch Ungerleider and Mishkin made lesions clean and neat Found two streams of vision flowing from cortical beat V1 starts the journey, splits the visual load Down the ventral highway or the dorsal road [Chorus] What pathway travels down, where pathway climbs up high Ventral stream says "what is it," dorsal asks "where am I" From V1 to V2, then the streams divide What goes to temporal, where to parietal side Two questions that your brain keeps asking every day What am I seeing and where does it lay [Verse 2] Ventral stream cascades through V2 then V4's gate Inferotemporal cortex seals the object's fate Cut this pathway and the monkey's vision breaks apart Sees the banana but can't name what fills its heart Recognition vanishes though the eyes still work fine The what pathway's damage cuts the meaning line [Chorus] What pathway travels down, where pathway climbs up high Ventral stream says "what is it," dorsal asks "where am I" From V1 to V2, then the streams divide What goes to temporal, where to parietal side Two questions that your brain keeps asking every day What am I seeing and where does it lay [Verse 3] Dorsal stream climbs upward through V2 and V3's maze MT processes motion in the visual haze Posterior parietal cortex maps the spatial scene Damage here destroys location's crystalline sheen Monkey knows it's food but can't reach out to grab The where pathway's broken, spatial sense gone bad [Verse 4] Human patients show the same divided sight Stroke victims lose their what or where overnight Visual agnosia when ventral stream is hurt Can't name a spoon but know where objects assert Optic ataxia from dorsal damage shows Reaching for a cup but missing where it goes [Bridge] Temporal lobe remembers faces, objects, forms Parietal lobe navigates through spatial storms One stream for identity, one for position Ancient pathways serving visual cognition Lesion studies revealed this dual design Two streams of consciousness, yours and mine [Chorus] What pathway travels down, where pathway climbs up high Ventral stream says "what is it," dorsal asks "where am I" From V1 to V2, then the streams divide What goes to temporal, where to parietal side Two questions that your brain keeps asking every day What am I seeing and where does it lay [Outro] So remember the split when you open your eyes What versus where, the brain's great disguise Processing vision through parallel lanes Ungerleider-Mishkin lives on in our brains
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