Cover legend: Models of the cortex from several primate species were registered to investigate how different areas of the primate cortex expand as a function of brain size. This image shows each model from the smallest species (marmoset) to the largest species (human). The models are not to scale and are colored by the amount of expansion: red indicates areas of relatively high expansion, and blue areas of relatively low expansion. The pattern of differential expansion is similar between marmosets and capuchins, marmosets and macaques, and macaques and humans. This suggests there is a general developmental pattern of cortical expansion in primates, which largely accounts for the differences in cortical layout that are observed between species. For more information, see Chaplin et al. (15120–15125).