Reflexive attention modulates processing of visual stimuli in human extrastriate cortex

Attention can be oriented reflexively to a location in space by an abrupt c hange in the visual scene. In the present study, we investigated the conseq uences of reflexive attention on the neural processing of visual stimuli. T he findings show that reflexively oriented attention produces modulations i n early sensory analysis at the same extrastriate neural focus as the earli est effects of voluntarily focused attention. In addition, stimulus process ing was found to be enhanced at later stages of analysis, which reflect sti mulus relevance. As is the case with behavioral measures of reflexive atten tion, these physiological enhancement effects are rapidly engaged but short -lived. As time passes between the initial attention-capturing event and su bsequent stimuli, the extrastriate effect reverses, and the enhancement of higher order processing subsides. These findings indicate that reflexive at tention is able to affect perceptions of the visual world by modulating neu ral processing as early as extrastriate visual cortex.