作者
Xiangrui Li, Zhong-Lin Lu, Bosco S Tjan, Barbara A Dosher, Wilson Chu
发表日期
2008/4/22
期刊
Proceedings of the national Academy of Sciences
卷号
105
期号
16
页码范围
6202-6207
出版商
National Academy of Sciences
简介
Covert attention can lead to improved performance in perceptual tasks. The neural and functional mechanisms of covert attention are still under investigation. Using both rapid event-related and mixed designs, we measured the blood oxygenation level-dependent functional MRI contrast response functions over the full range of contrast (0–100%) in the retinotopically defined early visual areas (V1, V2, V3, V3A, and V4) in humans. Covert attention increased both the baseline activities and contrast gains in the five cortical areas. The effect on baseline can be decomposed into a transient trial-by-trial component and a component across an entire attention block. On average, increase in contrast gain accounted for ≈88.0%, 28.5%, 12.7%, 35.9%, and 25.2% of the trial-by-trial effects of attention in the five areas, respectively, and 22.2%, 12.8%, 7.4%, 19.7%, and 17.3% of the total effects of attention in those areas …
引用总数
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X Li, ZL Lu, BS Tjan, BA Dosher, W Chu - Proceedings of the national Academy of Sciences, 2008