Gannon Patrick J, Kheck Nancy M, Braun Allen R, Holloway Ralph L
Department of Otolaryngology, Mount Sinai School of Medicine, New York 10029, USA.
Anat Rec A Discov Mol Cell Evol Biol. 2005 Nov;287(1):1128-41. doi: 10.1002/ar.a.20256.
We have previously demonstrated that leftward asymmetry of the planum temporale (PT), a brain language area, was not unique to humans since a similar condition is present in great apes. Here we report on a related area in great apes, the planum parietale (PP). PP in humans has a rightward asymmetry with no correlation to the L>R PT, which indicates functional independence. The roles of the PT in human language are well known while PP is implicated in dyslexia and communication disorders. Since posterior bifurcation of the sylvian fissure (SF) is unique to humans and great apes, we used it to determine characteristics of its posterior ascending ramus, an indicator of the PP, in chimpanzee and orangutan brains. Results showed a human-like pattern of R>L PP (P = 0.04) in chimpanzees with a nonsignificant negative correlation of L>R PT vs. R>L PP (CC = -0.3; P = 0.39). In orangutans, SF anatomy is more variable, although PP was nonsignificantly R>L in three of four brains (P = 0.17). We have now demonstrated human-like hemispheric asymmetry of a second language-related brain area in great apes. Our findings persuasively support an argument for addition of a new component to the comparative neuroanatomic complex that defines brain language or polymodal communication areas. PP strengthens the evolutionary links that living great apes may offer to better understand the origins of these progressive parts of the brain. Evidence mounts for the stable expression of a neural foundation for language in species that we recently shared a common ancestor with.
我们之前已经证明，颞平面（PT）作为大脑语言区域的左侧不对称并非人类所独有，因为在大猩猩中也存在类似情况。在此，我们报告大猩猩中一个相关区域，即顶平面（PP）。人类的PP存在右侧不对称，且与左侧大于右侧的PT无相关性，这表明其功能具有独立性。PT在人类语言中的作用已广为人知，而PP与阅读障碍和交流障碍有关。由于大脑外侧裂（SF）的后部分叉是人类和大猩猩所特有的，我们利用它来确定黑猩猩和猩猩大脑中其上升支的特征，上升支是PP的一个指标。结果显示，黑猩猩中存在右侧大于左侧的PP模式（P = 0.04），左侧大于右侧的PT与右侧大于左侧的PP呈非显著负相关（CC = -0.3；P = 0.39）。在猩猩中，SF的解剖结构更具变异性，尽管在四个大脑中有三个大脑的PP右侧大于左侧但不显著（P = 0.17）。我们现在已经证明了大猩猩中第二个与语言相关的脑区存在类似人类的半球不对称。我们的发现有力地支持了在比较神经解剖复合体中增加一个新成分的观点，该复合体定义了大脑语言或多模态交流区域。PP加强了现存大猩猩可能提供的进化联系，以更好地理解大脑这些进步部分的起源。越来越多的证据表明，在我们最近有共同祖先的物种中，存在语言神经基础的稳定表达。
