Edinburgh Imaging, School of Clinical Sciences, University of Edinburgh, Edinburgh, Scotland, EH16 4TJ, UK.
University Department of Psychiatry, Warneford Hospital, Oxford, England, OX3 7JX, UK.
Brain Struct Funct. 2019 Apr;224(3):1141-1150. doi: 10.1007/s00429-018-01818-0. Epub 2019 Jan 11.
The term "cerebral torque" refers to opposing right-left asymmetries of frontal and parieto-occipital regions. These are assumed to derive from a lateralized gradient of embryological development of the human brain. To establish the timing of its evolution, we computed and compared the torque, in terms of three principal features, namely petalia, shift, and bending of the inter-hemispheric fissure as well as the inter-hemispheric asymmetry of brain length, height and width for in vivo Magnetic Resonance Imaging (MRI) scans of 91 human and 78 chimpanzee brains. We found that the cerebral torque is specific to the human brain and that its magnitude is independent of brain size and that it comprises features that are inter-related. These findings are consistent with the concept that a "punctuational" genetic change of relatively large effect introduced lateralization in the hominid lineage. The existence of the cerebral torque remains an unsolved mystery and the present study provides further support for this most prominent structural brain asymmetry being specific to the human brain. Establishing the genetic origins of the torque may, therefore, have relevance for a better understanding on human evolution, the organisation of the human brain, and, perhaps, also aspects of the neural basis of language.
“大脑扭矩”一词是指额顶叶和枕顶叶区域的左右不对称。这些假设来源于人类大脑胚胎发育的侧向梯度。为了确定其进化的时间，我们计算并比较了 91 个人类和 78 只黑猩猩大脑的活体磁共振成像（MRI）扫描的三个主要特征，即大脑半球间裂的花瓣状、移位和弯曲，以及大脑长度、高度和宽度的大脑半球间不对称。我们发现，大脑扭矩是人类大脑特有的，其大小与大脑大小无关，而且它包含相互关联的特征。这些发现与“点状”遗传变化的概念一致，这种遗传变化具有相对较大的影响，导致了同源物谱系的偏侧化。大脑扭矩的存在仍然是一个未解之谜，本研究进一步支持了这种最显著的结构性大脑不对称是人类大脑特有的。因此，确定扭矩的遗传起源可能与更好地理解人类进化、人类大脑的组织以及语言的神经基础的某些方面有关。
