Spatial refinement of LGN receptive fields over the course of development. A, Examples of spike-triggered average receptive fields at P16 and in adulthood. Scale bar, 10°. B, Fraction of LGN neurons with a clearly mapped spike-triggered average receptive field across the course of development. C, Receptive field radius, from a Gaussian fit to the spatial STA, over the course of development. Circles represent individual single units. D, Average receptive field radius across the course of development.