In the healthy human brain, the processing of language is strongly lateralised, usually to the left hemisphere, while the processing of complex non-linguistic sounds recruits brain regions bilaterally. Here we asked whether the anterior temporal lobes, strongly implicated in semantic processing, are critical to this special treatment of spoken words. Nine patients with semantic dementia (SD) and fourteen age-matched controls underwent magnetoencephalography and structural MRI. Voxel based morphometry demonstrated the stereotypical pattern of SD: severe grey matter loss restricted to the anterior temporal lobes, with the left side more affected. During magnetoencephalography, participants listened to word sets in which identity and meaning were ambiguous until word completion, for example PLAYED versus PLATE. Whereas left-hemispheric responses were similar across groups, patients demonstrated increased right hemisphere activity 174-294 msec after stimulus disambiguation. Source reconstructions confirmed recruitment of right-sided analogues of language regions in SD: atrophy of anterior temporal lobes was associated with increased activity in right temporal pole, middle temporal gyrus, inferior frontal gyrus and supramarginal gyrus. Overall, the results indicate that anterior temporal lobes are necessary for normal and efficient lateralised processing of word identity by the language network.

中文翻译：

---

前颞叶对于有效地处理口语单词同一性是必要的。


在健康的人脑中，语言的处理是强烈侧化的，通常是左半球，而复杂的非语言声音的处理则需要两侧的大脑区域。在这里，我们询问与语义处理密切相关的前颞叶对于口语的这种特殊处理是否至关重要。 9 名语义性痴呆 (SD) 患者和 14 名年龄匹配的对照者接受了脑磁图和结构 MRI 扫描。基于体素的形态测量显示了 SD 的典型模式：严重的灰质损失仅限于前颞叶，左侧受影响更大。在脑磁图检查过程中，参与者听到的单词集在单词完成之前其身份和含义都是不明确的，例如“PLAYED”与“PLATE”。虽然各组的左半球反应相似，但在刺激消除歧义后 174-294 毫秒，患者表现出右半球活动增加。源重建证实了 SD 中语言区域右侧类似物的募集：前颞叶萎缩与右颞极、颞中回、额下回和缘上回活动增加相关。总体而言，结果表明前颞叶对于语言网络正常且有效地对单词同一性进​​行横向处理是必要的。