INSERM, U992, Neurospin, Gif/Yvette, France.
Neuroimage. 2011 Oct 1;58(3):716-23. doi: 10.1016/j.neuroimage.2011.06.016. Epub 2011 Jun 23.
In order to understand how genetic mutations might have favored language development in our species, we need a better description of the human brain at the beginning of life. As the linguistic network mainly involves the left perisylvian regions in adults, we used anatomical MRI to study the structural asymmetries of these regions in 14 preverbal infants. Our results show four significant asymmetries. First and foremost, they stress an important but little-known asymmetry: the larger depth of the right superior temporal sulcus (STS) at the base of Heschl's gyrus. Then, we characterized the early forward and upward shift of the posterior end of the right Sylvian fissure, the elongation of the left planum temporale as well as the thickening of the left Heschl's gyrus. The rightward bias of the STS is robust and large, and is not correlated with the leftward asymmetries of the planum and Heschl's gyrus, suggesting that different morphogenetic factors drive these asymmetries. As this sulcus is engaged in multiple high-level functions (e.g. language and theory of mind), and has been spotted as abnormal in several developmental disorders (e.g. schizophrenia, autism), this early rightward asymmetry should be further explored as a target for a genetic evolutionary pressure.
为了了解基因突变是如何促进我们人类语言发展的，我们需要更详细地描述生命早期人类大脑的情况。由于语言网络主要涉及成年人的左侧颞旁区，我们使用解剖 MRI 研究了 14 名言语前婴儿这些区域的结构不对称性。我们的结果显示出四个显著的不对称性。首先，它们强调了一个重要但鲜为人知的不对称性：在赫氏回基部右侧颞上沟（STS）的更深。然后，我们描述了右侧西尔维安裂后端的早期向前和向上移位、左侧颞平面的伸长以及左侧赫氏回的增厚。STS 的右偏是强大且显著的，并且与左侧平面和赫氏回的不对称性无关，这表明不同的形态发生因素驱动了这些不对称性。由于该脑回参与了多种高级功能（例如语言和心理理论），并且在多种发育障碍（例如精神分裂症、自闭症）中被发现异常，因此这种早期的右侧不对称性应该进一步探索，作为遗传进化压力的一个目标。
