pubmed-article:11252778 | pubmed:abstractText | Psychophysical and physiological studies have shown that attending to a stimulus can enhance its sensory processing. Functional imaging studies now reveal that attention can also modulate activity in sensory brain areas before stimulus onset, when the observer prepares to attend to an anticipated stimulus. These preparatory 'baseline shifts' in brain activity pose many new questions, and potentially offer new insights into the neural basis of perceptual awareness. | lld:pubmed |