[Verse 1] Deep in medial pallium, where the brain begins to form Cortical hem sits adjacent, like a biological storm Secreting Wnt3a signals, BMPs cascade and flow This transient organizer makes the hippocampus grow Without the hem's sweet whisper, no memory center forms Ablate this tiny region, watch the structure transform [Chorus] Build it up from the ground Lhx2 keeps the boundaries sound Prox1 marks the granule cells While the migration story tells Early born to inside-out CA neurons find their route Reelin guides them on their way In the developmental ballet [Verse 2] Lhx2 acts like a bouncer, represses hem expansion Guards the cortical territory, maintains the brain's mansion Emx1, Emx2 dancing with Foxg1 and Lef1 Prox1 stamps the dentate granules, marks each chosen one Septotemporal gradients paint the axis clear Morphogen rivers flowing, development sincere [Chorus] Build it up from the ground Lhx2 keeps the boundaries sound Prox1 marks the granule cells While the migration story tells Early born to inside-out CA neurons find their route Reelin guides them on their way In the developmental ballet [Verse 3] E10 to E18, pyramidal birth begins CA1 and CA3 neurons, the hippocampal twins E14 to E16 peak time, ventricular zone alive Radial glia highways guide them, help the cells arrive Inside-out like neocortex, early born sink deep Late arrivals climb above them, developmental leap [Verse 4] Neural stem cells keep dividing in the dentate gyrus zone Adult neurogenesis thriving, seeds that time has sown Subgranular layer harbors progenitors that wait To become new granule neurons, joining memory's fate CREB and BDNF signaling guide the plastic change In circuits ever-growing, learning's endless range [Bridge] Cajal-Retzius cells are waiting Reelin protein they're creating Scaffold for the great migration Neural architectural sensation From the ventricular zone they travel Watch the mystery unravel [Chorus] Build it up from the ground Lhx2 keeps the boundaries sound Prox1 marks the granule cells While the migration story tells Early born to inside-out CA neurons find their route Reelin guides them on their way In the developmental ballet [Outro] Wnt3a deletion, hippocampus fades away Lef1 knockout takes the dentate, selective price to pay From signaling to migration, structure finds its place In the choreographed formation of memory's embrace
← Module 5 — The assembled circuit: trisynaptic loop, direct paths, and rhythms | Module 7 — Wiring it up: axon guidance and the formation of each pathway →