Differences in human and Neanderthal brains set in first year of life
By ANITuesday, November 9, 2010
WASHINGTON - The difference between brains of newborn humans and Neanderthals takes shape specifically in the first year of life, a new study has suggested.
The brains of newborn humans and those of our extinct relatives are about the same size and appears rather similar overall.
The findings are based on comparisons of virtual imprints of the developing brain and surrounding structures (known as endocasts) derived from the skulls of modern and fossilized humans, including that of a newborn Neanderthal.
Philipp Gunz of the Max Planck Institute for Evolutionary Anthropology explained that the differences researchers observe in early brain development likely reflect changes in the underlying brain circuitry.
“In modern humans, the connections between diverse brain regions that are established in the first years of life are important for higher-order social, emotional, and communication functions.
“It is therefore unlikely that Neanderthals saw the world as we do,” said Gunz.
Because the range of brain sizes in Neanderthals overlaps with humans, many researchers had assumed that the cognitive capabilities of the two species were similar.
However, the new findings have challenged that notion.
In fact, the elongated overall shape of the braincase hasn’t changed much in the course of more than two million years of human evolution, despite a big increase in endocranium volume.
It is the globular braincases of modern humans that distinguish our own species from our closest fossil relatives and ancestors. The new results show that, at the time of birth, both Neanderthals and modern humans have elongated braincases, but only modern human endocasts change to a more globular shape in the first year of life.
“The distinct globular braincase shape of adult humans is therefore largely the result of an early brain development phase that is absent from Neanderthals,” said Gunz.
The findings were published in the Current Biology, a Cell Press publication. (ANI)
