Department of Neurology, University of Jena, Jena, Germany; Brain Imaging Center, University of Jena, Jena, Germany.
Neuroimage. 2010 Oct 15;53(1):189-95. doi: 10.1016/j.neuroimage.2010.05.087. Epub 2010 Jun 9.
The primary somatosensory cortex (SI) has been shown to encode the intensity of a stimulus applied to the contralateral side of the body. Recent studies have demonstrated that ipsilateral SI is also involved in the processing of somatosensory information. In this study, we investigated the dependence of the negative BOLD response in ipsilateral SI on the intensity of somatosensory stimulation. Functional MRI was performed in 12 healthy subjects during electrical median nerve stimulation at four different intensities. A monotonic relationship between stimulus intensity and the strength of the negative BOLD response in ipsilateral SI was found. Additionally, a psychophysiological experiment revealed tight coupling between the stimulus intensity applied to one hand and increased perceptual threshold of the other hand. These findings indicate a stimulus intensity-dependent inhibition of ipsilateral SI.
初级躯体感觉皮层（SI）已被证明可对施加于身体对侧的刺激的强度进行编码。最近的研究表明，同侧 SI 也参与了躯体感觉信息的处理。在这项研究中，我们调查了同侧 SI 中的负 BOLD 反应对躯体感觉刺激强度的依赖性。在 12 名健康受试者进行电刺激正中神经时，使用功能磁共振成像进行了四项不同强度的实验。结果发现，刺激强度与同侧 SI 中的负 BOLD 反应强度之间存在单调关系。此外，一项心理生理学实验表明，施加于一只手的刺激强度与另一只手的感知阈值增加之间存在紧密的耦合。这些发现表明同侧 SI 的抑制与刺激强度有关。
