Institute of Medical Psychology, Charité-Universitätsmedizin, 10099 Berlin, Germany.
Proc Natl Acad Sci U S A. 2010 Sep 14;107(37):16048-53. doi: 10.1073/pnas.1004801107. Epub 2010 Aug 30.
An important effect of sustained attention is the facilitation of perception. Although the term "sustained" suggests that this beneficial effect endures continuously as long as something is attended, we present electrophysiological evidence that perception at attended locations is actually modulated periodically. Subjects detected brief light flashes that were presented peripherally at locations that were either attended or unattended. We analyzed the correlation between detection performance for attended and unattended stimuli and the phase of ongoing EEG oscillations, which relate to subsecond fluctuations of neuronal excitability. Although on average, detection performance was improved by attention--indicated by reduced detection thresholds at attended locations--we found that detection performance for attended stimuli actually fluctuated over time along with the phase of spontaneous oscillations in the (≈7 Hz) frequency band just before stimulus onset. This fluctuation was absent for unattended stimuli. This pattern of results suggests that "sustained" attention in fact exerts its facilitative effect on perception in a periodic fashion.
持续注意力的一个重要作用是促进感知。虽然“持续”这个术语表明，只要有东西被注意，这种有益的效果就会持续不断，但我们提供了电生理证据表明，被注意位置的感知实际上是周期性地调节的。被试者检测了短暂的光闪烁，这些光闪烁在周边位置呈现，这些位置要么被注意到，要么没有被注意到。我们分析了被试者对注意和未注意刺激的检测性能与正在进行的 EEG 振荡相位之间的相关性，这些相位与神经元兴奋性的亚秒级波动有关。尽管平均而言，注意力提高了检测性能——表现为在注意位置的检测阈值降低——但我们发现，在刺激出现前的（≈7Hz）频率带的自发振荡相位，被注意刺激的检测性能实际上随时间波动。未被注意的刺激则没有这种波动。这种结果模式表明，“持续”注意力实际上是以周期性的方式对感知产生促进作用。
