Evidence for expansion of the precuneus in human evolution

• Type of Material: Article
• Authors: Emiliano Bruner, Centro Nacional de Investigación sobre la Evolución Humana; Todd M Preuss, Emory University; Xu Chen, Emory University; James K Rilling, Emory University
• Language: English
• Date: 2017-03-01
• Publisher: Springer Verlag (Germany)
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2016, Springer-Verlag Berlin Heidelberg.
• Final Published Version (URL): http://dx.doi.org/10.1007/s00429-015-1172-y
• Title of Journal or Parent Work: Brain Structure and Function
• ISSN: 1863-2653
• Volume: 222
• Issue: 2
• Start Page: 1053
• End Page: 1060
• Grant/Funding Information: This work was supported by National Institutes of Health Grants P01AG026423 and National Center for Research Resources P51RR165 (superceded by the Office of Research Infrastructure Programs/OD P51OD11132), by the John Templeton Foundation (award 40463), and by the Center for Behavioral Neuroscience. EB is funded by the Spanish Government (CGL2012-38434-C03-02/03) and by the Italian Institute of Anthropology.
• Keywords: Anatomy & Morphology; FUNCTIONAL CONNECTIVITY; Morphometrics; Evolutionary neuroanatomy; Science & Technology; ORGANIZATION; Parietal lobes; SUPERIOR PARIETAL CORTEX; HUMAN BRAIN EVOLUTION; Life Sciences & Biomedicine; Human evolution; Neurosciences & Neurology; ADULT HUMANS; Neurosciences; MONKEYS; GENUS HOMO; SHAPE; DEFAULT-MODE; CORTICAL SURFACE-AREA
• Research Categories: Biology, Neuroscience; Anthropology, Medical and Forensic; Psychology, Behavioral

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.