[Verse 1] Caudal, medial, tucked back in the skull, Parasubiculum's the fence, keeps the border full, Lateral neighbor's the LEC, smell's own address, This side reads geometry, not perfume, not scent, not guess. Layer two: stellate cells, evenly spaced like tile, Reelin lights them up, a honeycomb on file, Lamina dissecans — the canyon splitting floors, Parvalbumin inked dark, the interneuron corps. [Chorus] C'est la carte, mon cœur — où suis-je, où je vais, Grid et frontière, direction — jamais je m'égare, MEC, boussole, la métrique du pas, Où — c'est la question, et la réponse est là. [Verse 2] Postrhinal cortex hands over the scene, Presubiculum, parasubiculum keep the frame clean, Retrosplenial cortex ships the wide-angle view, Medial septum ticks theta — the clock stays true. Barely a whisper from the olfactory line, This circuit's not sniffing, it's mapping design — Little rose, little vine, little smell in the mix, MEC's built on boundary, on distance, on tricks. [Chorus] C'est la carte, mon cœur — où suis-je, où je vais, Grid et frontière, direction — jamais je m'égare, MEC, boussole, la métrique du pas, Où — c'est la question, et la réponse est là. [Verse 3] Grid cells fire in triangles, a lattice on repeat, Head-direction cells point wherever your nose meets the street, Border cells shout the second a wall's in your face, Speed cells clock your tempo, the rhythm of your pace, Object-vector cells flag the mug on the shelf, Conjunctive cells fuse angle and grid by themself, Theta's the drumbeat, seven cycles a breath, Stellate resonance hums — intrinsic, never rest. [Verse 4] Perforant path travels forward, dorsal down to ventral spread, Topographic mailing list, hippocampus fed, Layer five loops backward — retrosplenial, frontal call, Self-motion is the metric, no map upon the wall, Path integration: count each stride you've thrown, Then anchor to a border when the drift's overgrown. [Verse 5] Deep layers five and six send the story back downstream, To cortex, to memory, weaving the waking dream, Calbindin marks the patch, calbindin skips the band, Island cells guard the gate, a sentinel command, Disease creeps in early, tau finds this address first, Grid cells lose their lattice, the map begins to burst, Yet still the neurons whisper, coordinates in code, MEC keeps drawing borders on the oldest road. [Bridge] Sans les yeux, sans le nez, je sais où je suis, By the beat of my own legs, je trace mon chemin, L'odomètre du cerveau — pas après pas, La grille, la frontière — voilà où je vais. [Outro] Grid to border, vector to speed, Every cell's got an input it needs — MEC — the "where," the guide, the grid, Où je vais — the compass never hid. [Chorus] C'est la carte, mon cœur — où suis-je, où je vais, Grid et frontière, direction — jamais je m'égare, MEC, boussole, la métrique du pas, Où — c'est la question, et la réponse est là.
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