Department of Psychiatric Neurophysiology, University Hospital of Psychiatry Bern, University of Bern, Switzerland.
Brain Cogn. 2013 Mar;81(2):193-202. doi: 10.1016/j.bandc.2012.10.013. Epub 2012 Dec 20.
The deterioration of performance over time is characteristic for sustained attention tasks. This so-called "performance decrement" is measured by the increase of reaction time (RT) over time. Some behavioural and neurobiological mechanisms of this phenomenon are not yet fully understood. Behaviourally, we examined the increase of RT over time and the inter-individual differences of this performance decrement. On the neurophysiological level, we investigated the task-relevant brain areas where neural activity was modulated by RT and searched for brain areas involved in good performance (i.e. participants with no or moderate performance decrement) as compared to poor performance (i.e. participants with a steep performance decrement). For this purpose, 20 healthy, young subjects performed a carefully designed task for simple sustained attention, namely a low-demanding version of the Rapid Visual Information Processing task. We employed a rapid event-related functional magnetic resonance imaging (fMRI) design. The behavioural results showed a significant increase of RT over time in the whole group, and also revealed that some participants were not as prone to the performance decrement as others. The latter was statistically significant comparing good versus poor performers. Moreover, high BOLD-responses were linked to longer RTs in a task-relevant bilateral fronto-cingulate-insular-parietal network. Among these regions, good performance was associated with significantly higher RT-BOLD correlations in the pre-supplementary motor area (pre-SMA). We concluded that the task-relevant bilateral fronto-cingulate-insular-parietal network was a cognitive control network responsible for goal-directed attention. The pre-SMA in particular might be associated with the performance decrement insofar that good performers could sustain activity in this brain region in order to monitor performance declines and adjust behavioural output.
随着时间的推移，表现的恶化是持续注意力任务的特征。这种所谓的“表现下降”是通过随着时间的推移反应时间 (RT) 的增加来衡量的。这种现象的一些行为和神经生物学机制尚未完全理解。从行为上看，我们研究了随着时间的推移 RT 的增加以及这种表现下降的个体间差异。在神经生理学水平上，我们研究了与任务相关的大脑区域，其中神经活动被 RT 调节，并寻找与良好表现（即表现下降不大或中度的参与者）相关的大脑区域，而不是与较差表现（即表现下降陡峭的参与者）相关的大脑区域。为此，20 名健康的年轻受试者进行了一项精心设计的简单持续注意力任务，即低要求版本的快速视觉信息处理任务。我们采用了快速事件相关功能磁共振成像 (fMRI) 设计。行为结果表明，整个组的 RT 随着时间的推移呈显著增加，并且还表明，与其他人相比，有些参与者不太容易受到表现下降的影响。与良好表现者相比，这一点在统计学上是显著的。此外，在与任务相关的双侧额顶前扣带回-岛叶-顶叶网络中，高 BOLD 反应与较长的 RT 相关。在这些区域中，与良好表现者相关的是前补充运动区 (pre-SMA) 中的 RT-BOLD 相关性显著更高。我们得出结论，与任务相关的双侧额顶前扣带回-岛叶-顶叶网络是负责目标导向注意力的认知控制网络。特别是 pre-SMA 可能与表现下降有关，因为表现良好的人可以在该大脑区域维持活动，以监测表现下降并调整行为输出。
