The neocortex is the most recently evolved part of the brain, and, in this study, RNA sequencing was performed on individual layers of the prefrontal cortex from humans, macaques and chimpanzees and revealed that, although the expression of most genes was conserved across all three species, the number of genes showing a change in location of expression was far higher in humans than in chimpanzees and macaques, suggesting a greater cortical reorganization in the human evolutionary lineage than in that of other primates.