[Verse 1]
Deep behind the brainstem, folded tight like lace,
A cortex of granule cells humming in place,
Marr had a notion, Albus wrote it down,
Ito proved the engine turning skill around.
Climbing fibers fire when the reach goes wide,
One per Purkinje cell, riding the mistake inside,
Parallel fibers whisper, a thousand voices thin,
But when the climber shouts "wrong," that synapse wears thin.
[Chorus]
Kletterfaser schreit, der Fehler ist bekannt,
Die Synapse wird schwächer, LTD zur Hand,
Lern aus dem Irrtum, fein und klein,
Cerebellum, mach die Bewegung rein.
(Learn from error, fine and small,
Cerebellum tunes the reach, prevents the fall.)
[Verse 2]
Masao Ito watched the eye hold steady and still,
While the head was turning, defying its will,
Vestibulo-ocular reflex, gaze locked on a star,
Slip on the retina tells the brain how far.
He traced the long depression down to a single cell,
Climbing fiber paired with parallel, rang the bell,
Weaken what just fired, strengthen nothing new,
That's the rule of cerebellar learning, tried and true.
[Verse 3]
Thach and Martin handed dartboards and a prismatic wedge,
Throws went sideways first, clean off the ledge,
But steady throwers drifted back, toss by toss,
Rewriting the aim to cancel out the loss.
Patients with a wounded cerebellum, though,
Kept missing sideways, nowhere left to go,
No adapting, no correcting, the error stays the same,
Without the climbing fiber's voice, you can't reframe.
[Verse 4]
Richard Thompson rang a tone, then puffed the eye,
Rabbits learned to blink before the puff came by,
Lesion the interpositus, deep within the chain,
The learned blink vanishes, the reflex blink stays plain.
That tiny nucleus stores the timing of the blink,
Cerebellar memory, quicker than you think.
[Verse 5]
Mossy fibers carry the context of the plan,
Granule cells expand the code however they can,
Golgi cells inhibit, sculpting sparse and clean,
A pattern separation, the clearest ever seen.
Basket cells and stellate cells shape the timing fine,
Inhibition sharpens every Purkinje line,
So when the climbing fiber marks a motion gone astray,
The cortex has the context to rewrite the way.
[Bridge]
The cerebellum doesn't just correct what's done,
It adumbrates the motion before it's begun,
Sketching a forward model, faint and quick,
Predicting the feel of the hand on the stick,
Comparing the sketch to the sense that arrives,
Climbing fiber grades the gap, and the model revives.
[Chorus]
Kletterfaser schreit, der Fehler ist bekannt,
Die Synapse wird schwächer, LTD zur Hand,
Lern aus dem Irrtum, fein und klein,
Cerebellum, mach die Bewegung rein.
[Outro]
Error in, synapse thin, Purkinje falls quiet,
Ito's rule still runs the show, no need to deny it,
Vom Fehler lernt das Hirn, ganz leis und fein,
Cerebellum, immer lernend, will refined.