Jahanshahi M, Dirnberger G
Department of Clinical Neurology, Institute of Neurology and Medical Research Council, The National Hospital for Neurology and Neurosurgery, London, UK.
Neuropsychologia. 1999 Feb;37(2):181-90. doi: 10.1016/s0028-3932(98)00092-x.
Evidence from PET studies suggests that the dorsolateral prefrontal cortex (DLPFC) is involved in generation of random responses. We used TMS to examine the specific role of this area in random generation of responses, a task which requires holding information 'on line', suppression of habitual or stereotyped response patterns, intrinsic response generation, monitoring of responses and modification of production strategies. From the results of a previous study of the effects of TMS on random number generation, we proposed a network modulation model, whereby suppression of habitual responses is considered a key process of random response generation and is achieved through the modulatory influence of the left DLPFC over an associative network distributed in the superior temporal cortex. The aim of the present study was to further investigate the generality of this model by examining the effects of short trains of TMS over the left or right DLPFC or medial frontal cortex on random letter generation in healthy participants. TMS over the left DLPFC significantly increased non-randomness relative to control no stimulation trials, which was not obtained with TMS over the right DLPFC or medial frontal cortex. The results suggest the generality of network modulation model of random response generation.
正电子发射断层扫描（PET）研究的证据表明，背外侧前额叶皮质（DLPFC）参与随机反应的产生。我们使用经颅磁刺激（TMS）来研究该区域在随机反应产生中的具体作用，这一任务需要在线保持信息、抑制习惯性或刻板的反应模式、内在反应产生、反应监测以及生产策略的修改。根据之前一项关于TMS对随机数生成影响的研究结果，我们提出了一个网络调制模型，据此，习惯性反应的抑制被认为是随机反应产生的关键过程，并且是通过左DLPFC对分布于颞上皮质的联想网络的调制影响来实现的。本研究的目的是通过检查对健康参与者左或右DLPFC或内侧额叶皮质进行短串TMS刺激对随机字母生成的影响，进一步探究该模型的普遍性。相对于对照无刺激试验，对左DLPFC进行TMS刺激显著增加了非随机性，而对右DLPFC或内侧额叶皮质进行TMS刺激则未得到此结果。结果表明随机反应产生的网络调制模型具有普遍性。
