Department of Neurological and Vision Sciences, Section of Neurological Rehabilitation, Gianbattista Rossi Hospital, University of Verona, 37134 Verona, Italy.
Magn Reson Imaging. 2009 Nov;27(9):1175-86. doi: 10.1016/j.mri.2009.05.009. Epub 2009 Jul 22.
Passive electrical stimulation activates various human somatosensory cortical systems including the contralateral primary somatosensory area (SI), bilateral secondary somatosensory area (SII) and bilateral insula. The effect of stimulation frequency on blood oxygenation level-dependent (BOLD) activity remains unclear. We acquired 3-T functional magnetic resonance imaging (fMRI) in eight healthy volunteers during electrical median nerve stimulation at frequencies of 1, 3 and 10 Hz. During stimulation BOLD signal changes showed activation in the contralateral SI, bilateral SII and bilateral insula. Results of fMRI analysis showed that these areas were progressively active with the increase of rate of stimulation. As a major finding, the contralateral SI showed an increase of peak of BOLD activation from 1 to 3 Hz but reached a plateau during 10-Hz stimulation. Our finding is of interest for basic research and for clinical applications in subjects unable to perform cognitive tasks in the fMRI scanner.
被动电刺激激活了各种人类躯体感觉皮质系统，包括对侧初级躯体感觉区（SI）、双侧次级躯体感觉区（SII）和双侧脑岛。刺激频率对血氧水平依赖（BOLD）活动的影响尚不清楚。我们在 8 名健康志愿者中进行了 3-T 功能磁共振成像（fMRI），在 1、3 和 10 Hz 的电正中神经刺激期间。在刺激期间，BOLD 信号变化显示在对侧 SI、双侧 SII 和双侧脑岛中出现激活。fMRI 分析的结果表明，这些区域随着刺激率的增加而逐渐活跃。作为一个主要发现，对侧 SI 在 1 至 3 Hz 的刺激频率下显示出 BOLD 激活峰值的增加，但在 10 Hz 的刺激下达到了一个平台。我们的发现对于基础研究和对于无法在 fMRI 扫描仪中执行认知任务的受试者的临床应用具有重要意义。
