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：1999
卷号：96
期号：6
页码：3314-3319
DOI：10.1073/pnas.96.6.3314
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Functional MRI was used to test whether instructing subjects to attend to one or another location in a visual scene would affect neural activity in human primary visual cortex. Stimuli were moving gratings restricted to a pair of peripheral, circular apertures, positioned to the right and to the left of a central fixation point. Subjects were trained to perform a motion discrimination task, attending (without moving their eyes) at any moment to one of the two stimulus apertures. Functional MRI responses were recorded while subjects were cued to alternate their attention between the two apertures. Primary visual cortex responses in each hemisphere modulated with the alternation of the cue; responses were greater when the subject attended to the stimuli in the contralateral hemifield. The attentional modulation of the brain activity was about 25% of that evoked by alternating the stimulus with a uniform field.
