Hecht Erin E, Vijayakumar Suhas, Becker Yannick, Hopkins William D
Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA.
Neuroimaging Center, Focus Program Translational Neuroscience Johannes Gutenberg University Medical Center, Mainz, Germany.
Nat Commun. 2025 Apr 17;16(1):3681. doi: 10.1038/s41467-025-58784-5.
Whether language has its evolutionary origins in vocal or gestural communication has long been a matter of debate. In humans, the arcuate fasciculus, a major fronto-temporal white matter tract, is left-lateralized, is larger than in nonhuman apes, and is linked to language. However, the extent to which the arcuate fasciculus of nonhuman apes is linked to vocal and/or manual communication is currently unknown. Here, using probabilistic tractography in 67 chimpanzees (45 female, 22 male), we report that the chimpanzee arcuate fasciculus is not left-lateralized at the population level, in marked contrast with humans. However, individual variation in the anatomy and leftward asymmetry of the chimpanzee arcuate fasciculus is associated with individual variation in the use of both communicative gestures and communicative sounds under volitional orofacial motor control. This indicates that the arcuate fasciculus likely supported both vocal and gestural communication in the chimpanzee/human last common ancestor, 6-7 million years ago.
语言的进化起源是源于声音交流还是手势交流，长期以来一直是个有争议的问题。在人类中，弓状束是一条主要的额颞叶白质束，它在左侧更为发达，比非人类猿类的更大，并且与语言相关。然而，目前尚不清楚非人类猿类的弓状束与声音和/或手势交流的关联程度。在此，我们对67只黑猩猩（45只雌性，22只雄性）进行了概率性纤维束成像，结果表明，与人类形成鲜明对比的是，在群体水平上黑猩猩的弓状束并不偏向左侧。然而，黑猩猩弓状束在解剖结构和向左不对称方面的个体差异，与在意志性口面部运动控制下交流手势和交流声音的使用上的个体差异相关。这表明，在600 - 700万年前的黑猩猩/人类的最后一个共同祖先中，弓状束可能同时支持了声音和手势交流。
