Interhemispheric effect of parietal TMS on somatosensory response confirmed directly with concurrent TMS-fMRI.
Interhemispheric effect of parietal TMS on somatosensory response confirmed directly with concurrent TMS-fMRI.
复制标题
顶壁TMS对体感觉反应的半球间影响直接与并发的TMS-FMRI证实。
DOI：
10.1523/jneurosci.3043-08.2008
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发表时间：
2008-12-03
期刊：
影响因子：
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通讯作者：
Driver J
中科院分区：
文献类型：
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作者：
Blankenburg F;Ruff CC;Bestmann S;Bjoertomt O;Eshel N;Josephs O;Weiskopf N;Driver J
经颅磁刺激（TMS）已被用于记录一些明显的半球间影响行为，据报道，经颅磁刺激在右顶叶皮层上增强了同侧右手的触觉加工。然而，经颅磁刺激对这种明显的半球间影响的神经基础仍不清楚。本研究直接将经颅磁刺激与并发功能磁共振成像（fMRI）相结合进行研究。在两种感觉情境下，我们在右侧顶叶皮层以高强度或低强度应用10hz TMS脉冲：要么没有任何其他刺激，要么在参与者接受右手腕的中神经刺激时，该刺激投射到左侧初级体感皮层（SI）。对右顶叶皮层的经颅磁刺激影响左SI的BOLD信号，高强度与低强度的经颅磁刺激在右腕体感输入时增加了左SI信号，但在没有体感输入时减少了左SI信号。正如兴趣区域分析所揭示的那样，这种由顶叶经颅磁刺激在另一个半球上对SI的状态依赖性调节伴随着经颅磁刺激在丘脑中引起的相关影响模式。一项行为实验证实，同样的右顶叶TMS方案的10Hz脉冲导致对右正中神经阈附近电刺激的检测增强，该电刺激最初是在左S1处理的。我们的研究结果直接证实，通过右顶叶皮层的经颅磁刺激可以影响另一个半球的左SI处理，在没有体感输入的情况下产生竞争效应（可能是经胼胝体），但在驱动体感输入的情况下产生促进效应（可能涉及丘脑回路）。
Transcranial magnetic stimulation (TMS) has been used to document some apparent interhemispheric influences behaviorally, with TMS over right parietal cortex reported to enhance processing of touch for the ipsilateral right hand. However, the neural bases of such apparent interhemispheric influences from TMS remain unknown. Here, we studied this directly by combining TMS with concurrent functional magnetic resonance imaging (fMRI). We applied bursts of 10-Hz TMS over right parietal cortex, at high or low intensity, during two sensory contexts: either without any other stimulation, or while participants received median-nerve stimulation to the right wrist, which projects to left primary somatosensory cortex (SI). TMS to right parietal cortex affected BOLD signal in left SI, with high-versus-low intensity TMS increasing the left SI signal during right-wrist somatosensory input, but decreasing this in the absence of somatosensory input. This state-dependent modulation of SI by parietal TMS over the other hemisphere was accompanied by a related pattern of TMS-induced influences in thalamus, as revealed by region-of-interest analyses there. A behavioral experiment confirmed that the same right-parietal TMS protocol of 10Hz bursts led to enhanced detection of peri-threshold electrical stimulation of the right median nerve, which is initially processed in left S1. Our results confirm directly that TMS over right parietal cortex can affect processing in left SI of the other hemisphere, with rivalrous effects (possibly transcallosal) arising in the absence of somatosensory input, but facilitatory effects (possibly involving thalamic circuitry) in the presence of driving somatosensory input.