Dorsaint-Pierre Raquel, Penhune Virginia B, Watkins Kate E, Neelin Peter, Lerch Jason P, Bouffard Marc, Zatorre Robert J
Neuropsychology and Cognitive Neuroscience Unit, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
Brain. 2006 May;129(Pt 5):1164-76. doi: 10.1093/brain/awl055. Epub 2006 Mar 14.
Morphological asymmetries favouring the left hemisphere in the planum temporale (PT) and Heschl's gyrus (HG) have both been presumed to relate to the typical left-hemisphere dominance for language functions. However, a direct link between structure and function has not been clearly established. The present study investigates this issue by measuring the volume of the PT and HG on the MRI scans of epilepsy patients classified into three groups: left speech group (LSG; n = 20), right speech group (RSG; n = 11) and bilateral speech group (BSG; n = 13), as assessed by the intracarotid Sodium Amytal procedure. Additionally, an automatic voxel-based morphometry (VBM) analysis was performed to explore collateral structural asymmetries. Although leftward structural asymmetries were found in the PT, consistent with the literature, they did not relate to language lateralization. For HG we also replicated asymmetries favouring the left side; interestingly, three of the individuals within the RSG showed a strongly reversed asymmetry, but as a whole the structure-function relationship for HG was not obligatory. The VBM analysis revealed a grey-matter concentration difference in the posterior part of the inferior frontal gyrus (pars opercularis, corresponding functionally to Broca's area), which favoured the left hemisphere in the LSG, and the right hemisphere in the RSG. The findings suggest that this frontal cortical region bears a direct relationship to language lateralization, which may be related to use-dependent plasticity in patients with language reorganization.
颞平面（PT）和颞横回（HG）中有利于左半球的形态不对称性都被认为与语言功能典型的左半球优势有关。然而，结构与功能之间的直接联系尚未明确确立。本研究通过测量癫痫患者MRI扫描中PT和HG的体积来调查这个问题，这些患者被分为三组：左利语言组（LSG；n = 20）、右利语言组（RSG；n = 11）和双侧语言组（BSG；n = 13），通过颈动脉内注射异戊巴比妥钠程序进行评估。此外，还进行了基于体素的自动形态测量（VBM）分析，以探索相关的结构不对称性。尽管在PT中发现了向左的结构不对称性，与文献一致，但它们与语言侧化无关。对于HG，我们也复制了有利于左侧的不对称性；有趣的是，RSG中的三名个体表现出强烈的反向不对称性，但总体而言，HG的结构-功能关系并非必然。VBM分析显示，额下回后部（岛盖部，功能上对应于布洛卡区）存在灰质浓度差异，在LSG中有利于左半球，而在RSG中有利于右半球。研究结果表明，这个额叶皮质区域与语言侧化有直接关系，这可能与语言重组患者的使用依赖可塑性有关。
