Common inhibitory mechanism in human inferior prefrontal cortex revealed by event-related functional MRI
Common inhibitory mechanism in human inferior prefrontal cortex revealed by event-related functional MRI
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DOI：
10.1093/brain/122.5.981
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发表时间：
1999-05-01
期刊：
影响因子：
14.5
通讯作者：
Miyashita, Y
中科院分区：
文献类型：
--
作者：
Konishi, S;Nakajima, K;Miyashita, Y
人类前额叶皮层的一个主要功能是抑制一种持续的反应倾向，以适应不断变化的环境。该功能已被频繁地使用go/no-go任务和set-shifting任务（例如威斯康星州卡片分类测试（WCST））来研究。对人类和猴子的研究表明，背外侧前额叶皮质参与了这两种任务范式。然而，它仍然是未知的，在背外侧前额叶皮层的功能是本地化，是否有一个共同的抑制机制，用于这些任务范式，以及如何抑制功能作用于两个不同的目标，即去/不去任务中的去反应和认知设置在WCST。在这项研究的go/no-go任务中，受试者被指示响应（go试验）或不响应（no-go试验），这取决于提示刺激。与抑制功能相关的功能性磁共振成像（fMRI）信号本质上是瞬时的。因此，我们使用了fMRI（事件相关fMRI）的时间分辨率，通过它可以分别分析go和no-go试验中的瞬态信号并相互比较。我们发现，在右半球的额下沟后部显示短暂的no-go优势活动的焦点，这与受试者使用右手还是左手无关。这些结果提示，右下前额叶区的瞬时激活与反应抑制功能的神经机制有关，而且该区域与WCST中认知定势转换时瞬时激活的区域在空间上是重叠的。go/nogo任务中的瞬时信号在抑制功能瞬时表达后5s达到峰值，WCST的瞬时信号在瞬时表达后7s达到峰值，反映了两种抑制性任务范式中神经元活动持续时间的不同。这些结果表明，右下前额叶区共同参与了对不同靶点的抑制，在执行go/no-go任务期间的go反应和在执行WCST期间的认知设置。
Inhibition of an ongoing reaction tendency for adaptation to changing environments is a major function of the human prefrontal cortex. This function has been investigated frequently using the go/no-go task and set-shifting tasks such as the Wisconsin Card Sorting Test (WCST), Studies in humans and monkeys suggest the involvement of the dorsolateral prefrontal cortex in the two task paradigms. However, it remains unknown where in the dorsolateral prefrontal cortex this function is localized, whether a common inhibitory mechanism is used in these task paradigms and how this inhibitory function acts on two different targets, i,e, the go response in the go/no-go task and the cognitive set in the WCST. In the go/no-go task of this study, subjects were instructed to either respond (go trial) or not respond (no-go trial), depending on the cue stimulus presented. The signals of functional MRT (fMRI) related to the inhibitory function should be transient by nature. Thus, we used the temporal resolution of fMRI (event-related fMRI) by which transient signals in go and no-go trials can be analysed separately and compared with each other, We found a focus that showed transient no-go dominant activity in the posterior part of the inferior frontal sulcus in the right hemisphere, This was true irrespective of whether the subjects used their right or left hands. These results suggest that the transient activation in the right inferior prefrontal area is related to the neural mechanism underlying the response inhibition function, Furthermore, this area was found to be overlapped spatially with the area that was activated transiently during cognitive set shifting in the WCST The transient signals in the go/no-go task peaked 5s after the transient expression of the inhibitory function, and the transient signals in the WCST peaked 7s after the transient expression, reflecting different durations of neuronal activity in the two inhibitory task paradigms, These results imply that the right inferior prefrontal area is commonly involved in the inhibition of different targets, i,e, the go response during performance of the go/no-go task and the cognitive set during performance of the WCST.