The Evolution of the Posterior Parietal Cortex

Current research on the Posterior parietal cortex in primates has difficulty accommodating the inferior parietal lobule (Husain & Nachev, 2007). In this study neuroanatomical data from human and non human primates is used to investigate the evolutionary changes in the primate posterior parietal cortex (PPC); specifically the Inferior parietal area. All species were tested using three different investigations. One investigation included comparing the whole volume of the PPC against the volume of the whole cortex, a second comparing the volumes of the internal subdivisions of the PPC, more precisely the superior parietal lobule (SPL) and the inferior parietal lobule (IPL) against the volume of the whole PPC. The third investigation involves comparing the volume of individual structures against the volume of their respective hemispheres (e.g. the left hemisphere of the SPL against the volume of the entire SPL). 27 in vivo primate brain scans were analyzed in total using MRI scans from six different species including humans, great apes and monkeys. Image analysis software was used to calculate total brain volumes.