The researchers, including biological anthropologists, physicians and a computer scientist, looked at the CT scans and MRIs of infants with particular types of craniosynostosis a condition where one or more of the sutures -- fibrous bands that connect the bones -- of the baby's skull close too early and deform the skull and brain.
"We are interested in understanding craniosynostosis," says Dr. Joan T Richtsmeier, professor of biological anthropology at Penn State. "We would like to know why it happens, especially when it is not part of a syndrome, but when it occurs alone."
The researchers report in a recent early online publication of the Journal of Experimental Zoology: Molecular and Developmental Evolution: "Our study represents the first empirical evidence of phenotypic integration of brain and skull in 3D, although indirect evidence has been accumulating for years."
The researchers are also interested in understanding how the skull and brain change jointly through evolution. Vertebrate evolution shows a trend toward fewer skull and jaw bones and loss of some intercranial joints. While craniosynostosis is considered a pathology in modern humans, it shares with evolutionary history a reduction in cranial elements and coincident changes in the shape of the skull and brain. The researchers believe that studying craniosynostosis could shed light on the joint evolution of the brain and skull.
The two types of craniosynostosis the researchers studied were early closure of the sagittal suture the suture that runs down the center of the skull from front to back and unilateral coronal craniosynostosis, early closure of one side of the suture that runs across the top of the head from ear to ear.