Schematic of the signalling model. The model includes the PSD (yellow circle), a glutamate release site (blue cone) and AMPARs distributed within the PSD (orange cylinders). The length and depth of the cuboid is 700 nm and the height is 22.5 nm. AMPARs (N = 100) are uniformly distributed within the PSD (r = 295.4 nm). Glutamate molecules (N = 4000) are released from a point source opposite the centre of the PSD.