Tag Archives: chimpanzee

Face and cranial base

neauxDimitri Neaux and colleagues have published a series of comprehensive analyses on the influence of the cranial base in facial morphology of humans and apes. In one of the papers, they assessed the integration between the face and the two basicranial modules: the sagittal and the lateral cranial base. They tested the covariation between the three sets of 3D landmarks (face vs. midline base and face vs. lateral base) on modern humans and chimpanzees, separately. Only the correlation between the face and the lateral cranial base was significant, confirming the important role of the lateral cranial base in facial morphology. Though the levels of covariation were comparable, the patterns differed between the two species, as taller faces were associated with wider and shorter cranial fossae in chimps and with longer and narrower cranial fossae in humans. In another article, they assessed the relationship between cranial base flexion, facial orientation, and facial shape in modern humans, chimpanzees, and gorillas. Using 3D landmark analysis, they evaluated the within-species patterns of covariation, confirming the intraspecific relationship between facial structures and base flexion. Base flexion is associated with downward rotation of the facial block in both humans and chimps (confirming previous works) but not in gorillas. On the other hand, an upward rotation of the facial block is associated with anterior face vertical elongation on the three species. In humans, facial elongation is also associated with base flexion, which might have been selected during evolution to match the elongation of the nasomaxillary complex, as proposed before. The authors further tested whether increased base flexion is associated with the shortening of the facial length or with the decrease of facial projection. The relationship between base flexion and facial length was only observed in chimps, while facial projection was not related with cranial base flexion in chimpanzees and gorillas. In humans, contrary to what was expected, basicranial flexion was associated with increasing facial projection, which the authors attribute to sexual dimorphism, as males have increased base flexion and facial projection. Again, the main patterns of correlation differed between the species. Cranial base angle is negatively correlated with facial projection in modern humans, with facial length in chimps, and with the angle between the posterior-maxillary plane and the anterior facial plane in gorillas. As the authors conclude, these differences in the patterns of integration might reflect changes in the structural relationships between the face and the cranial base during hominoid evolution.

Sofia Pedro

Chimp brains

NCBSDear colleagues,
We are very pleased to announce the launch of the National Chimpanzee Brain Resource (NCBR) website. The NCBR is supported by the National Institute of Neurological Disorders and Stroke. We encourage you to browse the site, where you will find information about MRI datasets and tissue samples that are available by request to researchers. The NCBR website also serves as a data repository for studies that include chimpanzee brains. In the near future, the NCBR website will grow with the addition of a searchable database of behavioral and cognitive tasks, pedigrees, rearing history, neuroimaging data, and postmortem brain samples; chimpanzee brain atlas tools; and educational information about chimpanzee neuroscience. We invite you to make a request for MRI data or tissue. Please contribute your datasets that include chimpanzee brains to the repository. Our aim is for the NCBR to facilitate research advancement through the distribution of chimpanzee brain resources and dissemination of information, promoting the value of chimpanzees as a comparative reference to better understand the structure, function, and evolution of the human brain.

NCBR Directors
Chet Sherwood, Bill Hopkins, Todd Preuss