Department of Neuropsychiatry, Showa University School of Medicine, Tokyo 157-8577, Japan.
Cereb Cortex. 2010 May;20(5):1037-45. doi: 10.1093/cercor/bhp163. Epub 2009 Aug 14.
The present study investigated whether transcranial magnetic stimulation (TMS) to the parietal cortex improves the performance of healthy persons in a spatial working memory (WM) task. The effect of TMS on the frontal cortex was examined by measuring oxygenated hemoglobin (oxy-Hb) with near-infrared spectroscopy. Fifty-two healthy persons received either 100% resting motor threshold TMS at 5 Hz (real TMS) or sham TMS while engaged in a spatial WM task or a control visuospatial attention task. TMS was applied to either the left or the right parietal cortex during the delay period of the task. Reaction times improved in the spatial WM task, but not in the control task, with real TMS, whereas sham TMS had no effect. This improvement was only observed when TMS was applied to the right parietal cortex. Application of real TMS to the right parietal cortex also significantly increased frontal oxy-Hb levels during the WM task, but reduced oxy-Hb during the control task. These results suggest that TMS to the right parietal cortex may selectively facilitate spatial WM. Hemispheric asymmetry and the frontoparietal network theory may explain the observed effect of right parietal TMS on spatial WM.
本研究旨在探讨经颅磁刺激（TMS）对顶叶皮层是否能提高健康人群在空间工作记忆（WM）任务中的表现。通过近红外光谱测量氧合血红蛋白（oxy-Hb）来检测 TMS 对额叶皮层的影响。52 名健康人在进行空间 WM 任务或对照视觉空间注意任务时，分别接受 5Hz 的 100%静息运动阈值 TMS（真实 TMS）或假 TMS。在任务的延迟期，TMS 施加于左或右顶叶皮层。与假 TMS 相比，真实 TMS 可改善空间 WM 任务的反应时间，但不能改善对照任务的反应时间，而假 TMS 则没有影响。只有当 TMS 施加于右顶叶皮层时，才会观察到这种改善。在 WM 任务中，右顶叶皮层的真实 TMS 应用还显著增加了额叶 oxy-Hb 水平，但在对照任务中减少了 oxy-Hb。这些结果表明，右顶叶 TMS 可能选择性地促进空间 WM。半球不对称和额顶网络理论可以解释右顶叶 TMS 对空间 WM 的观察到的影响。
