title: The effects of feature attention on prestimulus cortical activity in the human visual system.
abstract: Covert attention affects prestimulus activity in the visual cortex. Although most studies investigating neural mechanisms of attention have focused on the effects of spatial attention, attention can also be directed to particular features. To investigate the spatiotemporal nature of feature attention, we measured subjects' brain activity using magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) while subjects attended to color or motion of a stimulus based on a visual cue, which was presented 1 s before the stimulus onset. We used the hierarchical Bayesian method that allows us to estimate cortical currents with MEG and fMRI data in the order of millimeters and milliseconds. When subjects attended to color, activity within the color-sensitive area (fusiform gyrus) was selectively enhanced within the prestimulus period. By contrast, when subjects attended to motion, activity within the motion-sensitive area (middle temporal gyrus) was selectively enhanced during this period. This effect was not seen in frontal, parietal, and lower visual areas. Additionally, this effect was transient rather than sustained, suggesting that it differs from temporal aspects of spatial attention. These results suggest that, although both spatial and feature attention modulate prestimulus activity within specific visual areas, neural mechanisms underlying these effects might be different.
authors.affiliation: Nara Institute of Science and Technology, Graduate School of Information Science, 8916-5 Takayama-cho, Ikoma-shi, Nara 630-0101, Japan. kazuhi-s@is.naist.jp
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Shibata
authors.forename: Noriko
authors.initials: N
authors.lastname: Yamagishi
authors.forename: Naokazu
authors.initials: N
authors.lastname: Goda
authors.forename: Taku
authors.initials: T
authors.lastname: Yoshioka
authors.forename: Okito
authors.initials: O
authors.lastname: Yamashita
authors.forename: Masa-aki
authors.initials: MA
authors.lastname: Sato
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Kawato
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D014793:Visual Cortex / Q000502:physiology*