期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2010
卷号：107
期号：37
页码：16048-16053
DOI：10.1073/pnas.1004801107
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：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 {theta} ({approx}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.
