title: Evidence for expansion of the precuneus in human evolution.
abstract: The evolution of neurocranial morphology in Homo sapiens is characterized by bulging of the parietal region, a feature unique to our species. In modern humans, expansion of the parietal surface occurs during the first year of life, in a morphogenetic stage which is absent in chimpanzees and Neandertals. A similar variation in brain shape among living adult humans is associated with expansion of the precuneus. Using MRI-derived structural brain templates, we compare medial brain morphology between humans and chimpanzees through shape analysis and geometrical modeling. We find that the main spatial difference is a prominent expansion of the precuneus in our species, providing further evidence of evolutionary changes associated with this area. The precuneus is a major hub of brain organization, a central node of the default-mode network, and plays an essential role in visuospatial integration. Together, the comparative neuroanatomical and paleontological evidence suggest that precuneus expansion is a neurological specialization of H. sapiens that evolved in the last 150,000 years that may be associated with recent human cognitive specializations.
authors.affiliation: Programa de Paleobiología, Centro Nacional de Investigación sobre la Evolución Humana, Burgos, Spain.
authors.forename: Emiliano
authors.initials: E
authors.lastname: Bruner
authors.affiliation: Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, USA.|Center for Translational Social Neuroscience, Atlanta, USA.|Center for Behavioral Neuroscience, Emory University, Atlanta, USA.
authors.forename: Todd M
authors.initials: TM
authors.lastname: Preuss
authors.affiliation: Department of Anthropology, Emory University, 1557 Dickey Drive, Atlanta, GA, 30322, USA.|Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, USA.
authors.forename: Xu
authors.initials: X
authors.lastname: Chen
authors.affiliation: Center for Translational Social Neuroscience, Atlanta, USA. jrillin@emory.edu.|Center for Behavioral Neuroscience, Emory University, Atlanta, USA. jrillin@emory.edu.|Department of Anthropology, Emory University, 1557 Dickey Drive, Atlanta, GA, 30322, USA. jrillin@emory.edu.|Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, USA. jrillin@emory.edu.|Yerkes National Primate Research Center, Emory University, Atlanta, USA. jrillin@emory.edu.
authors.forename: James K
authors.initials: JK
authors.lastname: Rilling
mesh_terms: D000328:Adult; D000818:Animals; D005075:Biological Evolution; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D002679:Pan troglodytes / Q000033:anatomy & histology / Q000502:physiology; D010296:Parietal Lobe / Q000033:anatomy & histology* / Q000502:physiology*; D013045:Species Specificity
keywords: Evolutionary neuroanatomy; Human evolution; Morphometrics; Parietal lobes