双语：初生婴儿脑部形状从未“进化”

屈联西

  2010年11月16日 环球时报


　　European scientists have discovered that the newborn brains of Neanderthals looked remarkably similar to human brains at birth and then began to diverge drastically over the first year of life。
　　A team led by paleoanthropologist Philipp Gunz of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, scanned the skulls of several Neanderthals, including a newborn, and mapped out the shape of the brain cavity。
　　Human and Neanderthal brains were remarkably similar in shape right after birth, the scientists found - perhaps because of the common need to squeeze a baby's head through its mother's birth canal. Then during the first year, human brains begin to morph from an elongated shape to a more rounded one. The Neanderthal brains, similar to chimpanzee brains, retained their oblong shape。
　　"We think shape indicates a difference in the speed of development," Gunz said, "because if you grow faster or slower, the brain shape changes differently.... We know from modern humans that the way you grow your brain affects the pattern of neural wiring."
　　The findings could help paleoanthropologists figure out the cognitive differences between modern humans and their extinct relatives - and when, exactly, those differences developed。
　　美国《芝加哥论坛报》13日报道称，欧洲科学家们近日发现，远古穴居人类婴儿的脑部形状和当今人类婴儿的脑部形状在出生时极为相似，但此后一年内二者大脑便朝不同的方向变化。
　　菲利普-冈茨是德国莱比锡马克思-普朗克进化人类学研究所的一名古人类学家，近日他带领团队对几个远古穴居人类(包括一名婴儿)进行了颅骨扫描，并还原了古人的脑部形状。
　　科学家们发现，当今人类大脑和远古穴居人类大脑的形状在刚出生时极为相似，这大概源于无论古今，人类出生时头部总要受到挤压的缘故。然而在此后的一年内，人类大脑开始变圆，远古穴居人类的脑部却还是和黑猩猩的脑部一样呈椭圆形。
　　“我们认为脑部形状揭示了大脑生长速度的差异，”冈茨说。“大脑生长的快慢决定了脑部形状变化的趋势....。。而通过对当今人类的研究，大脑的生长状况直接影响神经网络构造。”
　　这些新发现或可帮助古人类学家们找到当今人类与他们已灭绝了的远古祖先之间的认知差异，并明确这些差异始于何时。