[Verse 1] Deep in your midbrain, two stations await Processing light signals that seal your fate The pretectum watches for brightness to shift While SCN guards time's circadian drift When photons hit retina, messages race Through optic nerve pathways to each special place [Chorus] Pretectum makes pupils dance in sync SCN sets your body's clock in sync Light reflex and rhythm, they both do their thing Two guardians of sight that the midbrain will bring Test the pupil response when the cortex won't think Pretectum and SCN working in sync [Verse 2] Shine light in one eye, watch both pupils shrink That's consensual constriction, faster than you blink The pretectum's calling shots without asking your brain Clinical workhorse that doctors maintain Testing retina-to-midbrain when higher centers fail This reflex arc tells a neurological tale [Chorus] Pretectum makes pupils dance in sync SCN sets your body's clock in sync Light reflex and rhythm, they both do their thing Two guardians of sight that the midbrain will bring Test the pupil response when the cortex won't think Pretectum and SCN working in sync [Verse 3] Special ganglion cells, intrinsically bright Send ipRGC signals about day and night To suprachiasmatic nucleus they relay Information that keeps circadian sway Not image vision, but essential for life Entraining your rhythms through darkness and light [Verse 4] When trauma strikes hard and consciousness fades These ancient pathways still make the grades Pupillary light reflex remains intact A brainstem function that stays on track While cortical vision may be lost to injury Pretectum and SCN maintain their synergy [Bridge] When doctors shine flashlights in emergency rooms They're testing pretectum to banish their gloom While SCN whispers the time of day Through melanopsin's ancient display Two functions of eyesight beyond what we see Reflex and rhythm working perfectly [Chorus] Pretectum makes pupils dance in sync SCN sets your body's clock in sync Light reflex and rhythm, they both do their thing Two guardians of sight that the midbrain will bring Test the pupil response when the cortex won't think Pretectum and SCN working in sync [Chorus] Pretectum makes pupils dance in sync SCN sets your body's clock in sync Light reflex and rhythm, they both do their thing Two guardians of sight that the midbrain will bring Test the pupil response when the cortex won't think Pretectum and SCN working in sync [Outro] From retina's signals to midbrain's embrace These stations process light with elegant grace
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