Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Str. 22, 81675 Munich, Germany.
Faculty of Linguistics, Philology, & Phonetics, University of Oxford, Walton Street, Oxford OX1 2HG, UK.
Neuroimage. 2014 Nov 15;102 Pt 2:776-88. doi: 10.1016/j.neuroimage.2014.09.002. Epub 2014 Sep 9.
Repetitive navigated transcranial magnetic stimulation (rTMS) is increasingly used for preoperative cortical language mapping. Unlike direct cortical stimulation (DCS), and due to its non-invasive character, this technique can provide a map of the distribution of human language in the healthy brain as well as a dysfunctional brain. Although functional magnetic resonance imaging (fMRI) studies have reported interhemispheric functional connectivity between language structures, the way in which the right hemisphere helps bring about language function remains only partially investigated. The present study therefore uses rTMS as a virtual lesion model to investigate the right hemisphere's contribution to language processing in the healthy human brain.
Fifty healthy right-handed volunteers (25 males, 25 females, mean age 25.9 ± 5.4 years) underwent language mapping of the right hemisphere by rTMS combined with an object naming task. All errors induced by rTMS were categorized into six different error groups (no-response error, hesitation, performance error, neologism, semantic error, and phonological error). Afterwards, the error rates for each category were calculated and visualized through the results' being projected into the cortical parcellation system (CPS). To reveal CPS regions having similar functional properties, an additional principal component analysis (PCA) was performed.
rTMS induced 1485 naming errors out of the 9839 stimulation trains (error rate 15.1%). These errors were located mainly in the right hemisphere's homologues of the left hemisphere's visually cued overt speech area (middle superior temporal gyrus: mSTG) and in the sound-to-articulation dorsal pathway consisting of opercular inferior frontal gyrus (opIFG) and anterior and posterior supramarginal gyrus (aSMG, pSMG) in both male and female brains. In addition, rTMS caused many errors in the global language comprehension area in female brains (right posterior superior temporal gyrus: pSTG), in speech motor areas in the middle and ventral precentral and postcentral gyri (mPrG, vPrG, mPoG, vPoG), and in executive-function areas in the middle and posterior middle frontal gyri (mFMG, pMFG).
For the first time, the present study provides data on the right hemisphere's cortical regions causally related to single word production function (right opIFG, aSMG, pSMG, mSTG), and selectively in female brains (right pSTG), from a large sample of 50 healthy adult brains in a virtual-lesion design. Moreover, speech-motor control regions (right mPrG, vPrG, mPoG, vPoG) and cortical regions supporting language task performance (mMFG, pMFG) in the language-non-dominant right hemisphere are described.
重复经颅磁刺激（rTMS）越来越多地用于术前皮质语言定位。与直接皮质刺激（DCS）不同，由于其非侵入性，该技术可以提供健康大脑和功能障碍大脑中人类语言分布的图谱。尽管功能磁共振成像（fMRI）研究报告了语言结构之间的半球间功能连接，但右半球如何帮助实现语言功能仍在部分研究中。因此，本研究使用 rTMS 作为虚拟损伤模型，研究右半球在健康人脑中的语言处理贡献。
50 名健康右利手志愿者（25 名男性，25 名女性，平均年龄 25.9±5.4 岁）接受 rTMS 结合物体命名任务对右半球进行语言定位。rTMS 引起的所有错误均分为六类不同的错误组（无反应错误、犹豫、表现错误、新词错误、语义错误和语音错误）。之后，通过将结果投影到皮质分割系统（CPS）中，计算并可视化每个类别的错误率。为了揭示具有相似功能特性的 CPS 区域，还进行了额外的主成分分析（PCA）。
rTMS 在 9839 个刺激序列中诱导了 1485 次命名错误（错误率为 15.1%）。这些错误主要位于左半球视觉提示的口语区域（中颞上回：mSTG）和由外侧额下回（opIFG）和前后缘上回（aSMG，pSMG）组成的语音到发音背侧通路的右侧大脑半球的同系物中。此外，rTMS 在女性大脑的整体语言理解区域（右侧后颞上回：pSTG）、中前和后中央前回（mPrG，vPrG，mPoG，vPoG）的言语运动区域以及中后中央额回（mFMG，pMFG）的执行功能区域引起了许多错误。
本研究首次提供了在虚拟损伤设计中，从 50 名健康成年人大脑中的大量样本中，与单个单词产生功能（右侧 opIFG、aSMG、pSMG、mSTG）相关的右半球皮质区域的数据，以及选择性地在女性大脑中（右侧 pSTG）的数据。此外，还描述了语言非优势半球的言语运动控制区域（右侧 mPrG、vPrG、mPoG、vPoG）和支持语言任务表现的皮质区域（mMFG、pMFG）。
