Behavioral/Systems/Cognitive Attention Enhances the Neural Processing of Relevant Features and Suppresses the Processing of Irrelevant Features in Humans: A Functional Magnetic Resonance Imaging Study of the Stroop Task

We present a functional MRI experiment investigating the neural basis of feature-based attention in humans using the Stroop task. Cortical areas specifically involved in color processing and word reading were first identified in individual participants using indepen-dent tests. These areas were then probed during the Stroop task (in which participantsmust selectively attend to the font color of a word while ignoring theword itself).We found that activation in functionally defined color areas increased during the task relative to a neutral color-naming task while activation in functionally defined word areas decreased. These results are consistent with a biased competition model of feature-based attention in which the processing of attended features is enhanced and the processing of ignored features is suppressed. Key words: attention; Stroop task; feature-based; functional MRI; enhancement; suppressio