Princeton University, Princeton, New Jersey, USA.
Cogn Affect Behav Neurosci. 2010 May;10(2):298-315. doi: 10.3758/CABN.10.2.298.
Flexible control of behavior depends on the representation, maintenance, and updating of context information in working memory, which is thought to rely on the prefrontal cortex (PFC). However, in contrast to maintenance, the dynamics of context activation and updating have not been well studied. To identify neural signals associated with context updating, we compared event-related potentials associated with cues that did or did not provide task-relevant context information. The earliest effect of context was detected 200 msec following cue onset and had a scalp topography consistent with a generator in the PFC. Subsequent effects of context were detected at 400-700 msec following cue onset (P3b), with a broad scalp distribution spanning posterior areas, and during the final 300 msec preceding the target, with a probable generator in the medial frontal cortex. We propose that the effect of context on P2 is consistent with the onset of context updating in the PFC. Subsequent components may be indicative of activation of task-relevant posterior regions and context maintenance.
行为的灵活控制取决于工作记忆中对上下文信息的表示、维持和更新，这被认为依赖于前额叶皮层（PFC）。然而，与维持相比，上下文激活和更新的动态尚未得到很好的研究。为了识别与上下文更新相关的神经信号，我们比较了与提供或不提供任务相关上下文信息的线索相关的事件相关电位。上下文的最早影响在提示出现后 200 毫秒被检测到，头皮地形图与 PFC 中的发生器一致。随后，在提示出现后 400-700 毫秒（P3b）检测到上下文的后续影响，头皮分布广泛，跨越后部区域，并且在目标出现前的最后 300 毫秒期间，可能在中额皮层中有一个发生器。我们提出，P2 上的上下文效应与 PFC 中上下文更新的开始一致。随后的成分可能表明与任务相关的后部区域和上下文的激活。
