Schumacher Eric H, Cole Michael W, D'Esposito Mark
School of Psychology, Georgia Institute of Technology, Atlanta, GA 30332, USA.
Brain Res. 2007 Mar 9;1136(1):77-87. doi: 10.1016/j.brainres.2006.11.081. Epub 2007 Jan 16.
The ability to select an appropriate response among competing alternatives is a fundamental requirement for successful performance of a variety of everyday tasks. Recent research suggests that a frontal-parietal network of brain regions (including dorsal prefrontal, dorsal premotor and superior parietal cortices) mediate response selection for spatial material. Most of this research has used blocked experimental designs. Thus, the frontal-parietal activity reported may be due either to tonic activity across a block or to processing occurring at the trial level. Our current event-related fMRI study investigated response selection at the level of the trial in order to identify possible response selection sub-processes. In the study, participants responded to a visually presented stimulus with either a spatially compatible or incompatible manual response. On some trials, several seconds prior to stimulus onset, a cue indicated which task was to be performed. In this way we could identify separate brain regions for task preparation and task performance, if they exist. Our results showed that the frontal-parietal network for spatial response selection activated both during task preparation as well as during task performance. We found no evidence for preparation specific brain mechanisms in this task. These data suggest that spatial response selection and response preparation processes rely on the same neurocognitive mechanisms.
在各种日常任务中成功表现的一个基本要求是能够在相互竞争的选项中选择适当的反应。最近的研究表明，一个由大脑区域组成的额顶网络（包括背侧前额叶、背侧运动前区和顶上叶皮质）介导对空间材料的反应选择。这项研究大多采用了组块实验设计。因此，所报告的额顶叶活动可能是由于整个组块的持续性活动，或者是由于在试验水平上发生的加工过程。我们当前的事件相关功能磁共振成像研究在试验水平上调查反应选择，以识别可能的反应选择子过程。在该研究中，参与者对视觉呈现的刺激做出空间兼容或不兼容的手动反应。在一些试验中，在刺激开始前几秒，一个提示表明要执行的任务。通过这种方式，如果存在的话，我们可以识别出用于任务准备和任务执行的不同脑区。我们的结果表明，用于空间反应选择的额顶网络在任务准备期间以及任务执行期间均被激活。我们在该任务中没有发现特定于准备的脑机制的证据。这些数据表明，空间反应选择和反应准备过程依赖于相同的神经认知机制。
