Nature, Published online: 19 March 2025; doi:10.1038/d41586-025-00806-9The AMPA group of brain receptors have mostly been assumed to be calcium impermeable and so were not thought to contribute to the calcium-dependent mechanisms underlying learning and memory. Observations of calcium permeability in some AMPA-receptor subtypes now overturn those assumptions about these receptors properties and their roles in neuronal communication.