At the threshold where neurons speak to one another, a protein called CaMKIIα has long been suspected of holding the architecture of memory together — but the precise mechanics of its self-assembly remained unseen. Researchers across Japan have now watched, in real time, how these molecules link into chains when crowded and confined, just as they are inside a living synapse. The discovery not only illuminates a fundamental mechanism of learning but also offers a molecular window into why certain genetic mutations lead to intellectual disability — suggesting that the difference between remember