The 89th Annual Meeting of the American Association of Physical Anthropologists (2020)


Evolutionary changes in neurocranial structure do not correlate with cortical reorganization in humans

JOSÉ LUIS ALATORRE WARREN1, MARCIA PONCE DE LEÓN1, WILLIAM D. HOPKINS2,3 and CHRISTOPH P.E. ZOLLIKOFER1.

1Department of Anthropology, University of Zurich, 2Neuroscience Institute, Georgia State University, 3Division of Developmental and Cognitive Neuroscience, Yerkes National Primate Research Center

April 18, 2020 8:00AM, Diamond 5 Add to calendar

The human brain is approximately three times as large as that of our closest living relatives, the great apes, and exhibits autapomorphic sulcal patterns in several regions. Fossil neurocrania are regularly examined—both qualitatively and quantitatively—to document when and how these differences emerged during hominin evolution. Using MRI and same-individual CT/MRI data of 41 humans and 24 chimpanzees, we quantify the topographical relationships between brain sulci and internal and external neurocranial features, as well as the associated patterns of variation in and covariation between brain and neurocranial features. Our results show a posterior shift of the pre- and postcentral gyri in human relative to chimpanzee brains, reflecting reorganization of the frontal opercular region (Broca’s area in our species). Likewise, human neurocrania differ from those of chimpanzees in having relatively larger parietal bones and a more anterior position of the cerebellar fossa. Modularity/integration analysis suggests that changes in neurocranial and brain morphologies occurred largely independently during human evolution.

Funded by Swiss NSF grant #31003A_135470 to CPEZ.