[Verse 1]
Robot arm wraps around my wrist,
Pushes sideways with a hidden twist,
Velocity decides how hard it shoves,
My straight line bends to crescent loves,
First reach bows like an archer's string,
Curl field cuts me sideways, a stubborn thing,
Shadmehr watched it, ninety-four,
Mussa-Ivaldi counting every detour.
[Chorus]
Curve it, learn it, straighten the track,
Pull the field and the path curves back,
That's the ghost of a map in the brain,
An internal model, built from strain,
Fast forgets but slow stays true,
Two clocks ticking, learning you,
Opposite curve when the push is gone,
That's the signature written all along.
[Verse 2]
Practice, practice, a hundred tries,
The crescent flattens before my eyes,
Muscles whisper what the field will do,
Predicting the shove before it's true,
Then the robot cuts the power clean,
Arm swings opposite of what I'd seen,
Mirror-curve, the after-effect,
Proof a hidden model stood correct.
[Chorus]
Curve it, learn it, straighten the track,
Pull the field and the path curves back,
That's the ghost of a map in the brain,
An internal model, built from strain,
Fast forgets but slow stays true,
Two clocks ticking, learning you.
[Verse 3]
Swap the robot for a warped-up screen,
Cursor's lying about where you've been,
Thirty, forty-five degrees askew,
Visuomotor rotation twists the view,
Same old story, different disguise,
Hand relearns to trust its eyes,
Rotate the world and the brain complies,
Building new maps where the old path lies.
[Verse 4]
Smith and Ghazizadeh, Shadmehr too,
Two-thousand-six brought a sharper view,
Fast process leaps at the first mistake,
Quick to learn but quick to forsake,
Slow process creeps like a glacier's pace,
Stubborn memory, hard to erase,
Add them up and the hand corrects,
Layers of learning that intersect.
[Bridge]
Cut the cerebellum down,
Patients reach and the field wins the crown,
No prediction, no curve that bends,
Dysmetria — the overshoot that never ends,
Aim too far, then aim too near,
Jittery guesses, nothing clear,
The little brain writes the model we need,
Lose the writer, the hand can't read.
[Chorus]
Curve it, learn it, straighten the track,
Pull the field and the path curves back,
That's the ghost of a map in the brain,
An internal model, built from strain,
Fast forgets but slow stays true,
Two clocks ticking, learning you.
[Outro]
Curve then straight then curve reversed,
That's the lesson the cerebellum rehearsed,
Fast and slow, a two-part song,
The brain adapts — it was never wrong.