Mostofsky Stewart H, Schafer Joanna G B, Abrams Michael T, Goldberg Melissa C, Flower Abigail A, Boyce Avery, Courtney Susan M, Calhoun Vince D, Kraut Michael A, Denckla Martha B, Pekar James J
Developmental Cognitive Neurology, Kennedy Krieger Institute, 707 North Broadway, Baltimore, MD 21205, USA.
Brain Res Cogn Brain Res. 2003 Jul;17(2):419-30. doi: 10.1016/s0926-6410(03)00144-7.
Event-related fMRI was used to investigate the hypothesis that neural activity involved in response inhibition depends upon the nature of the response being inhibited. Two different Go/No-go tasks were compared-one with a high working memory load and one with low. The 'simple' Go/No-go task with low working memory load required subjects to push a button in response to green spaceships but not red spaceships. A 'counting' Go/No-go task (high working memory load) required subjects to respond to green spaceships as well as to those red spaceships preceded by an even number of green spaceships. In both tasks, stimuli were presented every 1.5 s with a 5:1 ratio of green-to-red spaceships. fMRI group data for each task were analyzed using random effects models to determine signal change patterns associated with Go events and No-go events (corrected P< or =0.05). For both tasks, Go responses were associated with signal change in the left primary sensorimotor cortex, supplementary motor area (SMA) proper, and anterior cerebellum (right>left). For the simple task, No-go events were associated with activation in the pre-SMA; the working memory-loaded 'counting' task elicited additional No-go activation in the right dorsolateral prefrontal cortex. The findings suggest that neural contributions to response inhibition may be task dependent; the pre-SMA appears necessary for inhibition of unwanted movements, while the dorsolateral prefrontal cortex is recruited for tasks involving increased working memory load.
参与反应抑制的神经活动取决于被抑制反应的性质。比较了两种不同的“是/否”任务——一种具有高工作记忆负荷，另一种具有低工作记忆负荷。工作记忆负荷低的“简单”“是/否”任务要求受试者对绿色太空船按下按钮，而对红色太空船则不按。“计数”“是/否”任务（高工作记忆负荷）要求受试者对绿色太空船以及前面有偶数个绿色太空船的红色太空船做出反应。在这两个任务中，刺激以每1.5秒呈现一次，绿色与红色太空船的比例为5:1。使用随机效应模型分析每个任务的功能磁共振成像组数据，以确定与“是”事件和“否”事件相关的信号变化模式（校正P≤0.05）。对于这两个任务，“是”反应都与左初级感觉运动皮层、辅助运动区（SMA）固有区和前小脑（右侧>左侧）的信号变化相关。对于简单任务，“否”事件与前辅助运动区的激活相关；工作记忆负荷较高的“计数”任务在右侧背外侧前额叶皮层引发了额外的“否”激活。研究结果表明，对反应抑制的神经贡献可能取决于任务；前辅助运动区似乎对抑制不必要的动作是必要的，而背外侧前额叶皮层则参与涉及增加工作记忆负荷的任务。
