Evidence for expansion of the precuneus in human evolution

• Published in: Brain Structure and Function Vol. 222; no. 2; pp. 1053 - 1060
• Main Authors: Bruner, Emiliano, Preuss, Todd M., Chen, Xu, Rilling, James K.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2017; Springer Nature B.V
• Subjects: Adult; Anatomy & physiology; Animals; Biological Evolution; Biomedical and Life Sciences; Biomedicine; Brain; Cell Biology; Cognition & reasoning; Evolution; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Neurology; Neurosciences; Pan troglodytes - anatomy & histology; Pan troglodytes - physiology; Parietal Lobe - anatomy & histology; Parietal Lobe - physiology; Short Communication; Species Specificity; Human evolution; Parietal lobes; Evolutionary neuroanatomy; Morphometrics
• ISSN: 1863-2653; 1863-2661; 1863-2661; 0340-2061
• DOI: 10.1007/s00429-015-1172-y

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.