The goal of the dissertation work outlined here was to investigate the influence of proximal processes contributing to evolutionary differences in phenotypes among primate species. There are numerous previous comparative analyses of gene expression between primate brain regions. However, primate brain tissue samples are relatively rare, and my results have contributed to the pre-existing data on more well-studied primates (i.e. humans, chimpanzees, macaques, marmosets) as well as produced information on more rarely-studied primates (i.e. patas monkey, siamang, spider monkey). Additionally, the primary visual cortex has not previously been as extensively studied at the level of gene expression as other brain regions in primates. My investigations of differences in cell biology between human and chimpanzee fibroblasts and iPSC-derived neural cells will contribute to the fields’ understanding of the influence of gene expression on differences in cell biology. While iPSC technology has been used extensively to investigate neurological disease in vitro, it has not been used to investigate differences in neural function between species. These data will be relevant both for determining proximate influences on evolutionary differences in neural function across primates and the limitations of use of non-human primate models of neurological disease.