University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3270, USA.
J Cogn Neurosci. 2010 Aug;22(8):1794-807. doi: 10.1162/jocn.2009.21325.
The ability to maintain focus and avoid distraction by goal-irrelevant stimuli is critical for performing many tasks and may be a key deficit in attention-related problems. Recent studies have demonstrated that irrelevant stimuli that are consciously perceived may be filtered out on a neural level and not cause the distraction triggered by subliminal stimuli. However, in everyday situations, suprathreshold stimuli often do capture attention, but the neural mechanisms by which some stimuli rapidly and automatically trigger distraction remain unknown. Here, we investigated the neural basis of distraction by utilizing a particularly strong form of distractor: the abrupt appearance of a new object. Our results revealed a competitive relation between brain regions coding the locations of the target and the distractor, with distractor processing increasing and target processing decreasing, but only when the distractor was a new object; an equivalent luminance change to an existing object neither generated distraction nor affected target processing. Results also revealed changes in neural activity in intraparietal sulcus (IPS) and temporo-parietal junction (TPJ) that were unique to the new object distractor condition. The strongest relations between behavioral distraction and neural activity were observed in these parietal regions. Furthermore, participants who were less susceptible to distraction showed a more consistent, albeit more moderate, level of activity in IPS and TPJ. The present results thus provide new evidence regarding the neural mechanisms underlying distraction and resistance to it.
保持专注并避免被目标无关刺激分散注意力的能力对于执行许多任务至关重要，并且可能是与注意力相关问题的关键缺陷。最近的研究表明，在神经水平上可以过滤掉有意识感知到的无关刺激，而不会引起潜意识刺激引发的分心。然而，在日常生活中，超阈值刺激通常会引起注意，但是某些刺激迅速而自动引发分心的神经机制尚不清楚。在这里，我们利用一种特别强的分心刺激形式：新物体的突然出现，来研究分心的神经基础。我们的研究结果揭示了编码目标和分心位置的大脑区域之间的竞争关系，随着分心处理的增加和目标处理的减少，但仅当分心是新物体时才会出现这种情况；与现有物体的等效亮度变化既不会产生分心，也不会影响目标处理。结果还揭示了在顶内沟（IPS）和颞顶联合区（TPJ）中出现的神经活动变化，这些变化仅在新物体分心条件下出现。在这些顶叶区域中，观察到行为分心与神经活动之间的最强关系。此外，对分心的敏感性较低的参与者在 IPS 和 TPJ 中表现出更一致但适度的活动水平。因此，当前的研究结果为分心和抵制分心的神经机制提供了新的证据。
