Tzourio N, Crivello F, Mellet E, Nkanga-Ngila B, Mazoyer B
Groupe d'Imagerie Neurofonctionnelle, UPRES EA 2127 Université de Caen and CEA LRC 13, Caen, France.
Neuroimage. 1998 Jul;8(1):1-16. doi: 10.1006/nimg.1998.0343.
In order to study the functional anatomy of hemispheric dominance for language comprehension we compared the patterns of activations and deactivations with PET and H(2)15O during a story-listening task in two groups of normal volunteers selected on the basis of their handedness. The reference task was a silent rest. The results showed asymmetrical temporal activations favoring the left hemisphere in right handers (RH) together with Broca's area and medial frontal activations. A rightward lateralization of deactivations located in the parietal and inferior temporal gyrus was also observed. In left handers (LH) the temporal activations were more symmetrical as were the parietal and inferior frontal deactivations. Broca's area and medial frontal gyrus activations were present in LH. The direct comparison of RH and LH activations revealed larger activations in the left superior temporal, in particular in the left planum temporale and temporal pole of RH, while LH activated an additional right middle temporal region. Individual analysis of LH differences images superimposed on individual MRI planes demonstrated an important variability of functional dominance, with two LH leftward lateralized, two symmetrical, and one showing a rightward lateralization of temporal activations. There was no relationship between functional dominance and handedness scores. These results are in accordance with data from aphasiology that suggest a greater participation of the right hemisphere in language processing in LH. In addition, the presence of bilateral deactivations of the dorsal route could support the assumption that LH ambilaterality concerns, in addition to language, other cognitive functions such as visuospatial processing.
为了研究语言理解的半球优势功能解剖学，我们在一项故事聆听任务中，使用正电子发射断层扫描（PET）和H(2)15O，比较了两组根据利手情况挑选出的正常志愿者的激活和失活模式。参照任务是静息状态。结果显示，右利手（RH）在颞叶的激活呈不对称性，左侧半球更占优势，同时布洛卡区和内侧额叶也有激活。还观察到顶叶和颞下回的失活向右半球侧化。在左利手（LH）中，颞叶激活更对称，顶叶和额下回的失活也是如此。布洛卡区和内侧额回激活在左利手中也存在。右利手和左利手激活的直接比较显示，右利手的左侧颞上回，特别是左侧颞平面和颞极有更大激活，而左利手还激活了右侧颞中回的一个额外区域。将左利手差异图像叠加在个体磁共振成像（MRI）平面上的个体分析表明，功能优势存在重要变异性，两名左利手的激活向左半球侧化，两名对称，一名颞叶激活向右半球侧化。功能优势与利手得分之间没有关系。这些结果与失语症学的数据一致，表明左利手中右半球在语言处理中的参与度更高。此外，背侧通路双侧失活的存在可能支持这样一种假设，即左利手的双侧性除了涉及语言外，还涉及其他认知功能，如视觉空间处理。
