A study of stimulus conditions of repetitive transcranial magnetic stimulation using neurophysiological neuroimaging techniques

本研究的目的是利用神经生理学技术探讨rTMS（重复经颅磁刺激）治疗的最佳刺激条件和治疗机制。本研究的主要结果如下：1。采用高频振荡（HFOs）方法研究了7例健康受试者慢速rTMS前后初级感觉区（0.5 Hz， 50次脉冲，80%运动阈值）的体感诱发电位（SEPs）HFOs的作用机制。受试者在真实经颅磁刺激后hfo的振幅和强度均有显著增加，而在假经颅磁刺激后无明显增加。这些结果提示，慢速rTMS可能直接增加皮层gaba能抑制性中间神经元的活性，并通过这些抑制性中间神经元抑制皮层的兴奋性，从而达到治疗效果。结果还表明，hfo是寻找rTMS治疗最佳刺激条件的客观指标之一。使用空间过滤MEG分析检查精神分裂症患者Stroop任务中背外侧前额叶皮层（DLPFC）的神经激活。我们几乎实时地估计了伴有/不伴有幻听的精神分裂症患者在Stroop任务中的神经激活。在200 ms的时间窗口内，以50 ms为步长，分析了100个不一致刺激反应的非平均脑磁图信号。在25-60 Hz波段，在每个时间窗内检查显示显著电流源密度（CSD）变化的皮质区域。与CSD显著下降相对应的DLPFC的短暂性神经激活是双侧的，正常对照组为左侧优势，非幻觉者为左侧偏侧，幻觉者为右侧偏侧，表明左侧DLPFC的功能障碍与幻听有关。这表明，我们的神经成像技术对于检查与患者临床特征和rTMS治疗效果相关的脑神经网络动力学是有用的。少

The aim of this study was to examine the optimum stimulus conditions and therapeutic mechanisms of rTMS (repetitive transcranial magnetic stimulation) therapy using neurophysiological techniques. The main results of this study are as follows.1.Mechanisms of therapeutic effects of rTMS investigated by HFOs (high frequency oscillations)HFOs of SEPs (somatosensory evoked potentials) in 7 healthy human subjects were recorded before and after slow rTMS on the primary sensory area (0.5 Hz, 50 pulses, 80% motor threshold). The subjects showed significant increase of the amplitude and the power of HFOs after the real rTMS, while they did not show it after the sham rTMS. These results suggest that the slow rTMS might directly increase the activity of the GABAergic inhibitory interneurons in the cortex and suppress cortical excitability through these inhibitory interneurons, causing the therapeutic effects. They also indicate that HFOs are one of the candidates of objective indicators to find th … More e optimum stimulus conditions for the rTMS therapies.2.Examination of neural activations in the dorsolateral prefrontal cortex (DLPFC) in the Stroop task in schizophrenic patients using a spatially filtered MEG analysis.We estimated neural activations in the Stroop task in nearly real time for schizophrenic patients with/without auditory hallucinations. One hundred unaveraged MEG signals during the incongruent stimulus responses were analyzed with a time window of 200 ms in steps of 50 ms. In the 25-60 Hz band, cortical regions that showed significant current source density (CSD) changes were examined for each time window. Transient neural activations in the DLPFC, corresponding to significantly decreased CSD, were bilateral with left-side dominancy for the normal controls, left-lateralized for the non-hallucinators and right-lateralized for the hallucinators, suggesting that the dysfunction in the left DLPFC was related to auditory hallucinations. It is suggested that our neuroimaging techniques are useful for examining the dynamics of the brain neural network in relation with clinical features of patients and effects of the rTMS therapies. Less