Research Imaging Centre, Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada; Division of Brain, Imaging and Behaviour - Systems Neuroscience, Toronto Western Research Institute, UHN, University of Toronto, Toronto, Ontario, Canada.
Brain Stimul. 2013 Sep;6(5):769-76. doi: 10.1016/j.brs.2013.02.002. Epub 2013 Mar 21.
Selection of the most appropriate response necessitates inhibition of competing or prepotent responses. It is important to characterize which cortical areas are relevant to achieve response inhibition. Using the stop signal task, previous imaging studies revealed consistent activation in the right pre-supplementary motor area (pre-SMA). However, imaging alone suffers from the limitation that it can only provide neuronal correlates and cannot establish causality between brain activation and behavior. Repetitive transcranial magnetic stimulation (rTMS) can be used to temporarily interfere with the function of a cortical area considered to play a specific role in the behavior. Thus, we combined rTMS with H(2)(15)O positron emission tomography (PET) scans during the stop signal task, to test whether rTMS-induced changes in excitability of the right pre-SMA influenced response inhibition. We found that rTMS over the pre-SMA increased the efficiency of the inhibitory control over prepotent ongoing responses. A significant interaction was present in the left inferior frontal gyrus (IFG) along with an increase in regional cerebral blood flow (rCBF) in the left pre-SMA, left IFG, right premotor and right inferior parietal cortex. These areas best fitted the path analysis model in the effective connectivity model. The results of this study suggest that stimulation of the right pre-SMA, by interfering with its activity, may have a significant impact on response inhibition.
选择最合适的反应需要抑制竞争或优势反应。重要的是要确定哪些皮层区域与实现反应抑制有关。使用停止信号任务，以前的成像研究揭示了右侧预备运动区（pre-SMA）的一致激活。然而，成像本身存在局限性，只能提供神经元相关性，不能确定大脑激活与行为之间的因果关系。重复经颅磁刺激（rTMS）可用于暂时干扰被认为在行为中起特定作用的皮层区域的功能。因此，我们在停止信号任务期间将 rTMS 与 H（2）（15）O 正电子发射断层扫描（PET）扫描结合使用，以测试 rTMS 诱导的右侧 pre-SMA 兴奋性变化是否影响反应抑制。我们发现 rTMS 刺激 pre-SMA 增加了对优势进行中反应的抑制控制效率。在左侧额下回（IFG）中存在显著的相互作用，同时左侧 pre-SMA、左侧 IFG、右侧运动前皮质和右侧下顶叶皮质的局部脑血流（rCBF）增加。这些区域最符合有效连接模型中的路径分析模型。这项研究的结果表明，通过干扰其活动刺激右侧 pre-SMA 可能对反应抑制产生重大影响。
